https://github.com/eclipse/eclipse-collections/eclipse-collections: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar 
/*
 * Copyright (c) 2016 Goldman Sachs.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompany this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */

package org.eclipse.collections.impl.parallel;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Collection;
import java.util.List;
import java.util.RandomAccess;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.eclipse.collections.api.block.function.Function;
import org.eclipse.collections.api.block.function.Function0;
import org.eclipse.collections.api.block.function.Function2;
import org.eclipse.collections.api.block.function.primitive.DoubleFunction;
import org.eclipse.collections.api.block.function.primitive.FloatFunction;
import org.eclipse.collections.api.block.function.primitive.IntFunction;
import org.eclipse.collections.api.block.function.primitive.LongFunction;
import org.eclipse.collections.api.block.predicate.Predicate;
import org.eclipse.collections.api.block.procedure.Procedure;
import org.eclipse.collections.api.block.procedure.Procedure2;
import org.eclipse.collections.api.block.procedure.primitive.ObjectIntProcedure;
import org.eclipse.collections.api.list.ListIterable;
import org.eclipse.collections.api.map.MutableMap;
import org.eclipse.collections.api.map.primitive.ObjectDoubleMap;
import org.eclipse.collections.api.map.primitive.ObjectLongMap;
import org.eclipse.collections.api.multimap.MutableMultimap;
import org.eclipse.collections.api.tuple.primitive.DoubleDoublePair;
import org.eclipse.collections.impl.block.factory.Functions0;
import org.eclipse.collections.impl.block.procedure.MultimapPutProcedure;
import org.eclipse.collections.impl.block.procedure.MutatingAggregationProcedure;
import org.eclipse.collections.impl.block.procedure.NonMutatingAggregationProcedure;
import org.eclipse.collections.impl.factory.Maps;
import org.eclipse.collections.impl.list.fixed.ArrayAdapter;
import org.eclipse.collections.impl.map.mutable.ConcurrentHashMap;
import org.eclipse.collections.impl.map.mutable.UnifiedMap;
import org.eclipse.collections.impl.map.mutable.primitive.ObjectDoubleHashMap;
import org.eclipse.collections.impl.map.mutable.primitive.ObjectLongHashMap;
import org.eclipse.collections.impl.multimap.list.SynchronizedPutFastListMultimap;
import org.eclipse.collections.impl.tuple.primitive.PrimitiveTuples;
import org.eclipse.collections.impl.utility.Iterate;

import static org.eclipse.collections.impl.factory.Iterables.iList;


The ParallelIterate class contains several parallel algorithms that work with Collections. All of the higher level parallel algorithms depend on the basic parallel algorithm named forEach. The forEach algorithm employs a batching fork and join approach. 
 All Collections that are not either a RandomAccess or List are first converted to a Java array using Iterate.toArray(Iterable<Object>), and then run with one of the ParallelArrayIterate.forEach methods. 
See Also:
/**
 * The ParallelIterate class contains several parallel algorithms that work with Collections.  All of the higher
 * level parallel algorithms depend on the basic parallel algorithm named {@code forEach}.  The forEach algorithm employs
 * a batching fork and join approach.
 * <p>
 * All Collections that are not either a {@link RandomAccess} or {@link List} are first converted to a Java array
 * using {@link Iterate#toArray(Iterable)}, and then run with one of the {@code ParallelArrayIterate.forEach} methods.
 *
 * @see ParallelArrayIterate
 */
public final class ParallelIterate
{
    static final int DEFAULT_MIN_FORK_SIZE = 10000;
    static final int AVAILABLE_PROCESSORS = Runtime.getRuntime().availableProcessors();
    static final int TASK_RATIO = 2;
    static final int DEFAULT_PARALLEL_TASK_COUNT = ParallelIterate.getDefaultTaskCount();
    static final ExecutorService EXECUTOR_SERVICE = ParallelIterate.newPooledExecutor(ParallelIterate.class.getSimpleName(), true);

    private ParallelIterate()
    {
        throw new AssertionError("Suppress default constructor for noninstantiability");
    }

    static boolean isExecutorShutdown()
    {
        return ParallelIterate.EXECUTOR_SERVICE.isShutdown();
    }

    static void shutdownExecutor()
    {
        ParallelIterate.EXECUTOR_SERVICE.shutdown();
    }

    
Iterate over the collection specified, in parallel batches using default runtime parameter values. The ObjectIntProcedure used must be stateless, or use concurrent aware objects if they are to be shared. 

e.g.

final Map<Integer, Object> chm = new ConcurrentHashMap<Integer, Object>(); ParallelIterate.forEachWithIndex(collection, new ObjectIntProcedure()
{
    public void value(Object object, int index)
    {
        chm.put(index, object);
    }
});



/**
     * Iterate over the collection specified, in parallel batches using default runtime parameter values.  The
     * {@code ObjectIntProcedure} used must be stateless, or use concurrent aware objects if they are to be shared.
     * <p>
     * e.g.
     * <pre>
     * {@code final Map<Integer, Object> chm = new ConcurrentHashMap<Integer, Object>();}
     * ParallelIterate.<b>forEachWithIndex</b>(collection, new ObjectIntProcedure()
     * {
     *     public void value(Object object, int index)
     *     {
     *         chm.put(index, object);
     *     }
     * });
     * </pre>
     */
    public static <T> void forEachWithIndex(
            Iterable<T> iterable,
            ObjectIntProcedure<? super T> objectIntProcedure)
    {
        ParallelIterate.forEachWithIndex(iterable, objectIntProcedure, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Iterate over the collection specified in parallel batches using the default runtime parameters.  The
ObjectIntProcedure used must be stateless, or use concurrent aware objects if they are to be shared.  The code
is executed against the specified executor.



e.g. final Map<Integer, Object> chm = new ConcurrentHashMap<Integer, Object>(); ParallelIterate.forEachWithIndex(collection, new ObjectIntProcedure()
{
    public void value(Object object, int index)
    {
        chm.put(index, object);
    }
}, executor);



Params:
  • executor – Use this executor for all execution.
/**
     * Iterate over the collection specified in parallel batches using the default runtime parameters.  The
     * ObjectIntProcedure used must be stateless, or use concurrent aware objects if they are to be shared.  The code
     * is executed against the specified executor.
     * <p>
     * <pre>e.g.
     * {@code final Map<Integer, Object> chm = new ConcurrentHashMap<Integer, Object>();}
     * ParallelIterate.<b>forEachWithIndex</b>(collection, new ObjectIntProcedure()
     * {
     *     public void value(Object object, int index)
     *     {
     *         chm.put(index, object);
     *     }
     * }, executor);
     * </pre>
     *
     * @param executor Use this executor for all execution.
     */
    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndex(
            Iterable<T> iterable,
            BT procedure,
            Executor executor)
    {
        ParallelIterate.forEachWithIndex(
                iterable,
                new PassThruObjectIntProcedureFactory<>(procedure),
                new PassThruCombiner<>(), executor);
    }

    
Iterate over the collection specified in parallel batches.  The
ObjectIntProcedure used must be stateless, or use concurrent aware objects if they are to be shared.  The
specified minimum fork size and task count are used instead of the default values.

Params:
  • minForkSize – Only run in parallel if input collection is longer than this.
  • taskCount –   How many parallel tasks to submit to the executor.
See Also:
/**
     * Iterate over the collection specified in parallel batches.  The
     * ObjectIntProcedure used must be stateless, or use concurrent aware objects if they are to be shared.  The
     * specified minimum fork size and task count are used instead of the default values.
     *
     * @param minForkSize Only run in parallel if input collection is longer than this.
     * @param taskCount   How many parallel tasks to submit to the executor.
     * @see #forEachWithIndex(Iterable, ObjectIntProcedure)
     */
    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndex(
            Iterable<T> iterable,
            BT procedure,
            int minForkSize,
            int taskCount)
    {
        ParallelIterate.forEachWithIndex(
                iterable,
                new PassThruObjectIntProcedureFactory<>(procedure),
                new PassThruCombiner<>(),
                minForkSize,
                taskCount);
    }

    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndex(
            Iterable<T> iterable,
            ObjectIntProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            Executor executor)
    {
        int taskCount = Math.max(
                ParallelIterate.DEFAULT_PARALLEL_TASK_COUNT,
                Iterate.sizeOf(iterable) / ParallelIterate.DEFAULT_MIN_FORK_SIZE);
        ParallelIterate.forEachWithIndex(
                iterable,
                procedureFactory,
                combiner,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                taskCount,
                executor);
    }

    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndex(
            Iterable<T> iterable,
            ObjectIntProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount)
    {
        ParallelIterate.forEachWithIndex(iterable, procedureFactory, combiner, minForkSize, taskCount, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndex(
            Iterable<T> iterable,
            ObjectIntProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        if (Iterate.notEmpty(iterable))
        {
            if (iterable instanceof RandomAccess || iterable instanceof ListIterable
                    && iterable instanceof List)
            {
                ParallelIterate.forEachWithIndexInListOnExecutor(
                        (List<T>) iterable,
                        procedureFactory,
                        combiner,
                        minForkSize,
                        taskCount,
                        executor);
            }
            else
            {
                ParallelIterate.forEachWithIndexInListOnExecutor(
                        ArrayAdapter.adapt((T[]) Iterate.toArray(iterable)),
                        procedureFactory,
                        combiner,
                        minForkSize,
                        taskCount,
                        executor);
            }
        }
    }

    public static <T, BT extends ObjectIntProcedure<? super T>> void forEachWithIndexInListOnExecutor(
            List<T> list,
            ObjectIntProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        int size = list.size();
        if (size < minForkSize)
        {
            BT procedure = procedureFactory.create();
            Iterate.forEachWithIndex(list, procedure);
            if (combiner.useCombineOne())
            {
                combiner.combineOne(procedure);
            }
            else
            {
                combiner.combineAll(iList(procedure));
            }
        }
        else
        {
            int threadCount = Math.min(size, taskCount);
            ObjectIntProcedureFJTaskRunner<T, BT> runner =
                    new ObjectIntProcedureFJTaskRunner<>(combiner, threadCount);
            runner.executeAndCombine(executor, procedureFactory, list);
        }
    }

    
Iterate over the collection specified in parallel batches using default runtime parameter values. The Procedure used must be stateless, or use concurrent aware objects if they are to be shared. 

e.g.

final Map<Object, Boolean> chm = new ConcurrentHashMap<Object, Boolean>(); ParallelIterate.forEach(collection, new Procedure()
{
    public void value(Object object)
    {
        chm.put(object, Boolean.TRUE);
    }
});



/**
     * Iterate over the collection specified in parallel batches using default runtime parameter values.  The
     * {@code Procedure} used must be stateless, or use concurrent aware objects if they are to be shared.
     * <p>
     * e.g.
     * <pre>
     * {@code final Map<Object, Boolean> chm = new ConcurrentHashMap<Object, Boolean>();}
     * ParallelIterate.<b>forEach</b>(collection, new Procedure()
     * {
     *     public void value(Object object)
     *     {
     *         chm.put(object, Boolean.TRUE);
     *     }
     * });
     * </pre>
     */
    public static <T> void forEach(Iterable<T> iterable, Procedure<? super T> procedure)
    {
        ParallelIterate.forEach(iterable, procedure, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Iterate over the collection specified in parallel batches using default runtime parameter values. The Procedure used must be stateless, or use concurrent aware objects if they are to be shared. 

e.g.

final Map<Object, Boolean> chm = new ConcurrentHashMap<Object, Boolean>(); ParallelIterate.forEachBatchSize(collection, new Procedure()
{
    public void value(Object object)
    {
        chm.put(object, Boolean.TRUE);
    }
}, 100);



/**
     * Iterate over the collection specified in parallel batches using default runtime parameter values.  The
     * {@code Procedure} used must be stateless, or use concurrent aware objects if they are to be shared.
     * <p>
     * e.g.
     * <pre>
     * {@code final Map<Object, Boolean> chm = new ConcurrentHashMap<Object, Boolean>();}
     * ParallelIterate.<b>forEachBatchSize</b>(collection, new Procedure()
     * {
     *     public void value(Object object)
     *     {
     *         chm.put(object, Boolean.TRUE);
     *     }
     * }, 100);
     * </pre>
     */
    public static <T> void forEach(Iterable<T> iterable, Procedure<? super T> procedure, int batchSize)
    {
        ParallelIterate.forEach(iterable, procedure, batchSize, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T> void forEach(Iterable<T> iterable, Procedure<? super T> procedure, int batchSize, Executor executor)
    {
        ParallelIterate.forEach(iterable, procedure, batchSize, ParallelIterate.calculateTaskCount(iterable, batchSize), executor);
    }

    
Iterate over the collection specified in parallel batches using default runtime parameter values and the specified executor. The Procedure used must be stateless, or use concurrent aware objects if they are to be shared. 
Params:
  • executor – Use this executor for all execution.
See Also:
/**
     * Iterate over the collection specified in parallel batches using default runtime parameter values
     * and the specified executor.
     * The {@code Procedure} used must be stateless, or use concurrent aware objects if they are to be shared.
     *
     * @param executor Use this executor for all execution.
     * @see #forEach(Iterable, Procedure)
     */
    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            BT procedure,
            Executor executor)
    {
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(procedure),
                new PassThruCombiner<>(),
                executor);
    }

    
Iterate over the collection specified in parallel batches using the specified minimum fork and task count sizes. The Procedure used must be stateless, or use concurrent aware objects if they are to be shared. 
Params:
  • minForkSize – Only run in parallel if input collection is longer than this.
  • taskCount –   How many parallel tasks to submit to the executor.
                   TODO: How does the taskCount relate to the number of threads in the executor?
See Also:
/**
     * Iterate over the collection specified in parallel batches using the specified minimum fork and task count sizes.
     * The {@code Procedure} used must be stateless, or use concurrent aware objects if they are to be shared.
     *
     * @param minForkSize Only run in parallel if input collection is longer than this.
     * @param taskCount   How many parallel tasks to submit to the executor.
     *                    TODO: How does the taskCount relate to the number of threads in the executor?
     * @see #forEach(Iterable, Procedure)
     */
    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            BT procedure,
            int minForkSize,
            int taskCount)
    {
        ParallelIterate.forEach(iterable, procedure, minForkSize, taskCount, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            BT procedure,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(procedure),
                new PassThruCombiner<>(),
                minForkSize,
                taskCount,
                executor);
    }

    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            Executor executor)
    {
        ParallelIterate.forEach(iterable, procedureFactory, combiner, ParallelIterate.DEFAULT_MIN_FORK_SIZE, executor);
    }

    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner)
    {
        ParallelIterate.forEach(iterable, procedureFactory, combiner, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Iterate over the collection specified in parallel batches using the default values for the task size.  The
ProcedureFactory can create stateful closures that will be collected and combined using the specified Combiner.



e.g. The ParallelIterate.select() implementation

 CollectionCombiner<T, SelectProcedure<T>> combiner = CollectionCombiner.forSelect(collection); ParallelIterate.forEach(collection,new SelectProcedureFactory<T>(predicate, taskSize), combiner, 1000); 


/**
     * Iterate over the collection specified in parallel batches using the default values for the task size.  The
     * ProcedureFactory can create stateful closures that will be collected and combined using the specified Combiner.
     * <p>
     * <pre>e.g. The <b>ParallelIterate.select()</b> implementation
     * <p>
     * {@code CollectionCombiner<T, SelectProcedure<T>> combiner = CollectionCombiner.forSelect(collection);}
     * ParallelIterate.<b>forEach</b>(collection,{@code new SelectProcedureFactory<T>(predicate, taskSize), combiner, 1000);}
     * </pre>
     */
    @SuppressWarnings("JavaDoc")
    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int batchSize)
    {
        ParallelIterate.forEach(iterable, procedureFactory, combiner, batchSize, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int batchSize,
            Executor executor)
    {
        ParallelIterate.forEach(iterable, procedureFactory, combiner, batchSize, ParallelIterate.calculateTaskCount(iterable, batchSize), executor);
    }

    
Iterate over the collection specified in parallel batches using the default values for the task size.  The
ProcedureFactory can create stateful closures that will be collected and combined using the specified Combiner.



e.g. The ParallelIterate.select() implementation

 int taskCount = Math.max(DEFAULT_PARALLEL_TASK_COUNT, collection.size() / DEFAULT_MIN_FORK_SIZE); final int taskSize = collection.size() / taskCount / 2; CollectionCombiner<T, SelectProcedure<T>> combiner = CollectionCombiner.forSelect(collection); ParallelIterate.forEach(collection,new SelectProcedureFactory<T>(predicate, taskSize), combiner, DEFAULT_MIN_FORK_SIZE, taskCount); 


/**
     * Iterate over the collection specified in parallel batches using the default values for the task size.  The
     * ProcedureFactory can create stateful closures that will be collected and combined using the specified Combiner.
     * <p>
     * <pre>e.g. The <b>ParallelIterate.select()</b> implementation
     * <p>
     * int taskCount = Math.max(DEFAULT_PARALLEL_TASK_COUNT, collection.size() / DEFAULT_MIN_FORK_SIZE);
     * final int taskSize = collection.size() / taskCount / 2;
     * {@code CollectionCombiner<T, SelectProcedure<T>> combiner = CollectionCombiner.forSelect(collection);}
     * ParallelIterate.<b>forEach</b>(collection,{@code new SelectProcedureFactory<T>(predicate, taskSize), combiner, DEFAULT_MIN_FORK_SIZE, taskCount);}
     * </pre>
     */
    @SuppressWarnings("JavaDoc")
    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount)
    {
        ParallelIterate.forEach(iterable, procedureFactory, combiner, minForkSize, taskCount, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, BT extends Procedure<? super T>> void forEach(
            Iterable<T> iterable,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        if (Iterate.notEmpty(iterable))
        {
            if (iterable instanceof BatchIterable)
            {
                ParallelIterate.forEachInBatchWithExecutor(
                        (BatchIterable<T>) iterable,
                        procedureFactory,
                        combiner,
                        minForkSize,
                        taskCount,
                        executor);
            }
            else if ((iterable instanceof RandomAccess || iterable instanceof ListIterable)
                    && iterable instanceof List)
            {
                ParallelIterate.forEachInListOnExecutor(
                        (List<T>) iterable,
                        procedureFactory,
                        combiner,
                        minForkSize,
                        taskCount,
                        executor);
            }
            else
            {
                ParallelArrayIterate.forEachOn(
                        (T[]) Iterate.toArray(iterable),
                        procedureFactory,
                        combiner,
                        minForkSize,
                        taskCount,
                        executor);
            }
        }
    }

    public static <T, BT extends Procedure<? super T>> void forEachInListOnExecutor(
            List<T> list,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        int size = list.size();
        if (size < minForkSize)
        {
            BT procedure = procedureFactory.create();
            Iterate.forEach(list, procedure);
            if (combiner.useCombineOne())
            {
                combiner.combineOne(procedure);
            }
            else
            {
                combiner.combineAll(iList(procedure));
            }
        }
        else
        {
            int threadCount = Math.min(size, taskCount);
            ProcedureFJTaskRunner<T, BT> runner =
                    new ProcedureFJTaskRunner<>(combiner, threadCount);
            runner.executeAndCombine(executor, procedureFactory, list);
        }
    }

    public static <T, BT extends Procedure<? super T>> void forEachInBatchWithExecutor(
            BatchIterable<T> set,
            ProcedureFactory<BT> procedureFactory,
            Combiner<BT> combiner,
            int minForkSize,
            int taskCount,
            Executor executor)
    {
        int size = set.size();
        if (size < minForkSize)
        {
            BT procedure = procedureFactory.create();
            set.forEach(procedure);
            if (combiner.useCombineOne())
            {
                combiner.combineOne(procedure);
            }
            else
            {
                combiner.combineAll(iList(procedure));
            }
        }
        else
        {
            int threadCount = Math.min(size, Math.min(taskCount, set.getBatchCount((int) Math.ceil((double) size / (double) taskCount))));
            BatchIterableProcedureFJTaskRunner<T, BT> runner =
                    new BatchIterableProcedureFJTaskRunner<>(combiner, threadCount);
            runner.executeAndCombine(executor, procedureFactory, set);
        }
    }

    
Same effect as Iterate.select(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches. 
See Also:
Returns:The selected elements. The Collection will be of the same type as the input (List or Set)
and will be in the same order as the input (if it is an ordered collection).
/**
     * Same effect as {@link Iterate#select(Iterable, Predicate)}, but executed in parallel batches.
     *
     * @return The selected elements. The Collection will be of the same type as the input (List or Set)
     * and will be in the same order as the input (if it is an ordered collection).
     * @see ParallelIterate#select(Iterable, Predicate, boolean)
     */
    public static <T> Collection<T> select(
            Iterable<T> iterable,
            Predicate<? super T> predicate)
    {
        return ParallelIterate.select(iterable, predicate, false);
    }

    
Same effect as Iterate.select(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches, and with a potentially reordered result. 
Params:
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The selected elements. The Collection will be of the same type (List or Set) as the input.
/**
     * Same effect as {@link Iterate#select(Iterable, Predicate)}, but executed in parallel batches,
     * and with a potentially reordered result.
     *
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The selected elements. The Collection will be of the same type (List or Set) as the input.
     */
    public static <T> Collection<T> select(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            boolean allowReorderedResult)
    {
        return ParallelIterate.select(iterable, predicate, null, allowReorderedResult);
    }

    
Same effect as Iterate.select(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches, and writing output into the specified collection. 
Params:
  • target –               Where to write the output.
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The 'target' collection, with the selected elements added.
/**
     * Same effect as {@link Iterate#select(Iterable, Predicate)}, but executed in parallel batches,
     * and writing output into the specified collection.
     *
     * @param target               Where to write the output.
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The 'target' collection, with the selected elements added.
     */
    public static <T, R extends Collection<T>> R select(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            R target,
            boolean allowReorderedResult)
    {
        return ParallelIterate.select(
                iterable,
                predicate,
                target,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE,
                allowReorderedResult);
    }

    
Same effect as Iterate.select(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches, and writing output into the specified collection. 
Params:
  • target –               Where to write the output.
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The 'target' collection, with the selected elements added.
/**
     * Same effect as {@link Iterate#select(Iterable, Predicate)}, but executed in parallel batches,
     * and writing output into the specified collection.
     *
     * @param target               Where to write the output.
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The 'target' collection, with the selected elements added.
     */
    public static <T, R extends Collection<T>> R select(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            R target,
            int batchSize,
            Executor executor,
            boolean allowReorderedResult)
    {
        FastListSelectProcedureCombiner<T> combiner = new FastListSelectProcedureCombiner<>(iterable, target, 10, allowReorderedResult);
        FastListSelectProcedureFactory<T> procedureFactory = new FastListSelectProcedureFactory<>(predicate, batchSize);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                ParallelIterate.calculateTaskCount(iterable, batchSize),
                executor);
        return (R) combiner.getResult();
    }

    private static <T> int calculateTaskCount(Iterable<T> iterable, int batchSize)
    {
        if (iterable instanceof BatchIterable<?>)
        {
            return ParallelIterate.calculateTaskCount((BatchIterable<?>) iterable, batchSize);
        }
        return ParallelIterate.calculateTaskCount(Iterate.sizeOf(iterable), batchSize);
    }

    private static <T> int calculateTaskCount(BatchIterable<T> batchIterable, int batchSize)
    {
        return Math.max(2, batchIterable.getBatchCount(batchSize));
    }

    private static int calculateTaskCount(int size, int batchSize)
    {
        return Math.max(2, size / batchSize);
    }

    
Same effect as Iterate.reject(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches. 
See Also:
Returns:The rejected elements. The Collection will be of the same type as the input (List or Set)
and will be in the same order as the input (if it is an ordered collection).
/**
     * Same effect as {@link Iterate#reject(Iterable, Predicate)}, but executed in parallel batches.
     *
     * @return The rejected elements. The Collection will be of the same type as the input (List or Set)
     * and will be in the same order as the input (if it is an ordered collection).
     * @see ParallelIterate#reject(Iterable, Predicate, boolean)
     */
    public static <T> Collection<T> reject(
            Iterable<T> iterable,
            Predicate<? super T> predicate)
    {
        return ParallelIterate.reject(iterable, predicate, false);
    }

    
Same effect as Iterate.reject(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches, and with a potentially reordered result. 
Params:
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The rejected elements. The Collection will be of the same type (List or Set) as the input.
/**
     * Same effect as {@link Iterate#reject(Iterable, Predicate)}, but executed in parallel batches,
     * and with a potentially reordered result.
     *
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The rejected elements. The Collection will be of the same type (List or Set) as the input.
     */
    public static <T> Collection<T> reject(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            boolean allowReorderedResult)
    {
        return ParallelIterate.reject(iterable, predicate, null, allowReorderedResult);
    }

    
Same effect as Iterate.reject(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches, and writing output into the specified collection. 
Params:
  • target –               Where to write the output.
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The 'target' collection, with the rejected elements added.
/**
     * Same effect as {@link Iterate#reject(Iterable, Predicate)}, but executed in parallel batches,
     * and writing output into the specified collection.
     *
     * @param target               Where to write the output.
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The 'target' collection, with the rejected elements added.
     */
    public static <T, R extends Collection<T>> R reject(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            R target,
            boolean allowReorderedResult)
    {
        return ParallelIterate.reject(
                iterable,
                predicate,
                target,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE,
                allowReorderedResult);
    }

    public static <T, R extends Collection<T>> R reject(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            R target,
            int batchSize,
            Executor executor,
            boolean allowReorderedResult)
    {
        FastListRejectProcedureCombiner<T> combiner = new FastListRejectProcedureCombiner<>(iterable, target, 10, allowReorderedResult);
        FastListRejectProcedureFactory<T> procedureFactory = new FastListRejectProcedureFactory<>(predicate, batchSize);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                ParallelIterate.calculateTaskCount(iterable, batchSize),
                executor);
        return (R) combiner.getResult();
    }

    
Same effect as Iterate.count(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches. 
Returns:The number of elements which satisfy the predicate.
/**
     * Same effect as {@link Iterate#count(Iterable, Predicate)}, but executed in parallel batches.
     *
     * @return The number of elements which satisfy the predicate.
     */
    public static <T> int count(Iterable<T> iterable, Predicate<? super T> predicate)
    {
        return ParallelIterate.count(iterable, predicate, ParallelIterate.DEFAULT_MIN_FORK_SIZE, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Same effect as Iterate.count(Iterable<Object>, Predicate<? super Object>), but executed in parallel batches. 
Returns:The number of elements which satisfy the predicate.
/**
     * Same effect as {@link Iterate#count(Iterable, Predicate)}, but executed in parallel batches.
     *
     * @return The number of elements which satisfy the predicate.
     */
    public static <T> int count(Iterable<T> iterable, Predicate<? super T> predicate, int batchSize, Executor executor)
    {
        CountCombiner<T> combiner = new CountCombiner<>();
        CountProcedureFactory<T> procedureFactory = new CountProcedureFactory<>(predicate);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                executor);
        return combiner.getCount();
    }

    
Same effect as Iterate.collect(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches. 
See Also:
Returns:The collected elements. The Collection will be of the same type as the input (List or Set)
and will be in the same order as the input (if it is an ordered collection).
/**
     * Same effect as {@link Iterate#collect(Iterable, Function)},
     * but executed in parallel batches.
     *
     * @return The collected elements. The Collection will be of the same type as the input (List or Set)
     * and will be in the same order as the input (if it is an ordered collection).
     * @see ParallelIterate#collect(Iterable, Function, boolean)
     */
    public static <T, V> Collection<V> collect(
            Iterable<T> iterable,
            Function<? super T, V> function)
    {
        return ParallelIterate.collect(iterable, function, false);
    }

    
Same effect as Iterate.collect(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and with potentially reordered result. 
Params:
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The collected elements. The Collection will be of the same type
(List or Set) as the input.
/**
     * Same effect as {@link Iterate#collect(Iterable, Function)}, but executed in parallel batches,
     * and with potentially reordered result.
     *
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The collected elements. The Collection will be of the same type
     * (List or Set) as the input.
     */
    public static <T, V> Collection<V> collect(
            Iterable<T> iterable,
            Function<? super T, V> function,
            boolean allowReorderedResult)
    {
        return ParallelIterate.collect(iterable, function, null, allowReorderedResult);
    }

    
Same effect as Iterate.collect(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into the specified collection. 
Params:
  • target –               Where to write the output.
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The 'target' collection, with the collected elements added.
/**
     * Same effect as {@link Iterate#collect(Iterable, Function)}, but executed in parallel batches,
     * and writing output into the specified collection.
     *
     * @param target               Where to write the output.
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The 'target' collection, with the collected elements added.
     */
    public static <T, V, R extends Collection<V>> R collect(
            Iterable<T> iterable,
            Function<? super T, V> function,
            R target,
            boolean allowReorderedResult)
    {
        return ParallelIterate.collect(
                iterable,
                function,
                target,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE,
                allowReorderedResult);
    }

    public static <T, V, R extends Collection<V>> R collect(
            Iterable<T> iterable,
            Function<? super T, V> function,
            R target,
            int batchSize,
            Executor executor,
            boolean allowReorderedResult)
    {
        int size = Iterate.sizeOf(iterable);
        FastListCollectProcedureCombiner<T, V> combiner = new FastListCollectProcedureCombiner<>(iterable, target, size, allowReorderedResult);
        int taskCount = ParallelIterate.calculateTaskCount(iterable, batchSize);
        FastListCollectProcedureFactory<T, V> procedureFactory = new FastListCollectProcedureFactory<>(function, size / taskCount);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                taskCount,
                executor);
        return (R) combiner.getResult();
    }

    public static <T, V> Collection<V> flatCollect(
            Iterable<T> iterable,
            Function<? super T, Collection<V>> function)
    {
        return ParallelIterate.flatCollect(iterable, function, false);
    }

    public static <T, V> Collection<V> flatCollect(
            Iterable<T> iterable,
            Function<? super T, Collection<V>> function,
            boolean allowReorderedResult)
    {
        return ParallelIterate.flatCollect(iterable, function, null, allowReorderedResult);
    }

    public static <T, V, R extends Collection<V>> R flatCollect(
            Iterable<T> iterable,
            Function<? super T, Collection<V>> function,
            R target,
            boolean allowReorderedResult)
    {
        return ParallelIterate.flatCollect(
                iterable,
                function,
                target,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE,
                allowReorderedResult);
    }

    public static <T, V, R extends Collection<V>> R flatCollect(
            Iterable<T> iterable,
            Function<? super T, Collection<V>> function,
            R target,
            int batchSize,
            Executor executor,
            boolean allowReorderedResult)
    {
        int size = Iterate.sizeOf(iterable);
        int taskCount = ParallelIterate.calculateTaskCount(iterable, batchSize);
        int taskSize = size / taskCount;
        FlatCollectProcedureCombiner<T, V> combiner =
                new FlatCollectProcedureCombiner<>(iterable, target, size, allowReorderedResult);
        FlatCollectProcedureFactory<T, V> procedureFactory = new FlatCollectProcedureFactory<>(function, taskSize);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                taskCount,
                executor);
        return (R) combiner.getResult();
    }

    
See Also:
Returns:The collected elements. The Collection will be of the same type as the input (List or Set)
and will be in the same order as the input (if it is an ordered collection).
/**
     * Same effect as {@link Iterate#collectIf(Iterable, Predicate, Function)},
     * but executed in parallel batches.
     *
     * @return The collected elements. The Collection will be of the same type as the input (List or Set)
     * and will be in the same order as the input (if it is an ordered collection).
     * @see ParallelIterate#collectIf(Iterable, Predicate, Function, boolean)
     */
    public static <T, V> Collection<V> collectIf(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            Function<? super T, V> function)
    {
        return ParallelIterate.collectIf(iterable, predicate, function, false);
    }

    
Same effect as Iterate.collectIf(Iterable<Object>, Predicate<? super Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and with potentially reordered results. 
Params:
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The collected elements. The Collection will be of the same type
as the input (List or Set)
/**
     * Same effect as {@link Iterate#collectIf(Iterable, Predicate, Function)},
     * but executed in parallel batches, and with potentially reordered results.
     *
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The collected elements. The Collection will be of the same type
     * as the input (List or Set)
     */
    public static <T, V> Collection<V> collectIf(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            Function<? super T, V> function,
            boolean allowReorderedResult)
    {
        return ParallelIterate.collectIf(iterable, predicate, function, null, allowReorderedResult);
    }

    
Same effect as Iterate.collectIf(Iterable<Object>, Predicate<? super Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into the specified collection. 
Params:
  • target –               Where to write the output.
  • allowReorderedResult – If the result can be in a different order.
                            Allowing reordering may yield faster execution.
Returns:The 'target' collection, with the collected elements added.
/**
     * Same effect as {@link Iterate#collectIf(Iterable, Predicate, Function)},
     * but executed in parallel batches, and writing output into the specified collection.
     *
     * @param target               Where to write the output.
     * @param allowReorderedResult If the result can be in a different order.
     *                             Allowing reordering may yield faster execution.
     * @return The 'target' collection, with the collected elements added.
     */
    public static <T, V, R extends Collection<V>> R collectIf(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            Function<? super T, V> function,
            R target,
            boolean allowReorderedResult)
    {
        return ParallelIterate.collectIf(
                iterable,
                predicate,
                function,
                target,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE,
                allowReorderedResult);
    }

    public static <T, V, R extends Collection<V>> R collectIf(
            Iterable<T> iterable,
            Predicate<? super T> predicate,
            Function<? super T, V> function,
            R target,
            int batchSize,
            Executor executor,
            boolean allowReorderedResult)
    {
        FastListCollectIfProcedureCombiner<T, V> combiner = new FastListCollectIfProcedureCombiner<>(iterable, target, 10, allowReorderedResult);
        FastListCollectIfProcedureFactory<T, V> procedureFactory = new FastListCollectIfProcedureFactory<>(function, predicate, batchSize);
        ParallelIterate.forEach(
                iterable,
                procedureFactory,
                combiner,
                batchSize,
                ParallelIterate.calculateTaskCount(iterable, batchSize),
                executor);
        return (R) combiner.getResult();
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function)
    {
        return ParallelIterate.groupBy(iterable, function, ParallelIterate.DEFAULT_MIN_FORK_SIZE, ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, K, V> MutableMap<K, V> aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator)
    {
        return ParallelIterate.aggregateBy(
                iterable,
                groupBy,
                zeroValueFactory,
                nonMutatingAggregator,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE);
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator,
            R mutableMap)
    {
        return ParallelIterate.aggregateBy(
                iterable,
                groupBy,
                zeroValueFactory,
                nonMutatingAggregator,
                mutableMap,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE);
    }

    public static <T, K, V> MutableMap<K, V> aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator,
            int batchSize)
    {
        return ParallelIterate.aggregateBy(
                iterable,
                groupBy,
                zeroValueFactory,
                nonMutatingAggregator,
                batchSize,
                ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator,
            R mutableMap,
            int batchSize)
    {
        return ParallelIterate.aggregateBy(
                iterable,
                groupBy,
                zeroValueFactory,
                nonMutatingAggregator,
                mutableMap,
                batchSize,
                ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, K, V> MutableMap<K, V> aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator,
            int batchSize,
            Executor executor)
    {
        return ParallelIterate.aggregateBy(
                iterable,
                groupBy,
                zeroValueFactory,
                nonMutatingAggregator,
                ConcurrentHashMap.newMap(),
                batchSize,
                executor);
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Function2<? super V, ? super T, ? extends V> nonMutatingAggregator,
            R mutableMap,
            int batchSize,
            Executor executor)
    {
        NonMutatingAggregationProcedure<T, K, V> nonMutatingAggregationProcedure =
                new NonMutatingAggregationProcedure<>(mutableMap, groupBy, zeroValueFactory, nonMutatingAggregator);
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(nonMutatingAggregationProcedure),
                Combiners.<Procedure<T>>passThru(),
                batchSize,
                executor);
        return mutableMap;
    }

    public static <T, K, V> MutableMap<K, V> aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator)
    {
        return ParallelIterate.aggregateInPlaceBy(
                iterable,
                groupBy,
                zeroValueFactory,
                mutatingAggregator,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE);
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator,
            R mutableMap)
    {
        return ParallelIterate.aggregateInPlaceBy(
                iterable,
                groupBy,
                zeroValueFactory,
                mutatingAggregator,
                mutableMap,
                ParallelIterate.DEFAULT_MIN_FORK_SIZE);
    }

    public static <T, K, V> MutableMap<K, V> aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator,
            int batchSize)
    {
        return ParallelIterate.aggregateInPlaceBy(
                iterable,
                groupBy,
                zeroValueFactory,
                mutatingAggregator,
                batchSize,
                ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator,
            R mutableMap,
            int batchSize)
    {
        return ParallelIterate.aggregateInPlaceBy(
                iterable,
                groupBy,
                zeroValueFactory,
                mutatingAggregator,
                mutableMap,
                batchSize,
                ParallelIterate.EXECUTOR_SERVICE);
    }

    public static <T, K, V> MutableMap<K, V> aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator,
            int batchSize,
            Executor executor)
    {
        MutableMap<K, V> map = ConcurrentHashMap.newMap();
        MutatingAggregationProcedure<T, K, V> mutatingAggregationProcedure =
                new MutatingAggregationProcedure<>(map, groupBy, zeroValueFactory, mutatingAggregator);
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(mutatingAggregationProcedure),
                Combiners.<Procedure<T>>passThru(),
                batchSize,
                executor);
        return map;
    }

    public static <T, K, V, R extends MutableMap<K, V>> R aggregateInPlaceBy(
            Iterable<T> iterable,
            Function<? super T, ? extends K> groupBy,
            Function0<? extends V> zeroValueFactory,
            Procedure2<? super V, ? super T> mutatingAggregator,
            R mutableMap,
            int batchSize,
            Executor executor)
    {
        MutatingAggregationProcedure<T, K, V> mutatingAggregationProcedure =
                new MutatingAggregationProcedure<>(mutableMap, groupBy, zeroValueFactory, mutatingAggregator);
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(mutatingAggregationProcedure),
                Combiners.<Procedure<T>>passThru(),
                batchSize,
                executor);
        return mutableMap;
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V, R extends MutableMultimap<K, V>> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function,
            R concurrentMultimap)
    {
        return ParallelIterate.groupBy(iterable, function, concurrentMultimap, ParallelIterate.DEFAULT_MIN_FORK_SIZE);
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V, R extends MutableMultimap<K, V>> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function,
            R concurrentMultimap,
            int batchSize)
    {
        return ParallelIterate.groupBy(iterable, function, concurrentMultimap, batchSize, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function,
            int batchSize)
    {
        return ParallelIterate.groupBy(iterable, function, batchSize, ParallelIterate.EXECUTOR_SERVICE);
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function,
            int batchSize,
            Executor executor)
    {
        return ParallelIterate.groupBy(iterable, function, SynchronizedPutFastListMultimap.newMultimap(), batchSize, executor);
    }

    
Same effect as Iterate.groupBy(Iterable<Object>, Function<? super Object,? extends Object>), but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap. 
/**
     * Same effect as {@link Iterate#groupBy(Iterable, Function)},
     * but executed in parallel batches, and writing output into a SynchronizedPutFastListMultimap.
     */
    public static <K, V, R extends MutableMultimap<K, V>> MutableMultimap<K, V> groupBy(
            Iterable<V> iterable,
            Function<? super V, ? extends K> function,
            R concurrentMultimap,
            int batchSize,
            Executor executor)
    {
        ParallelIterate.forEach(
                iterable,
                new PassThruProcedureFactory<>(new MultimapPutProcedure<>(concurrentMultimap, function)),
                Combiners.<Procedure<V>>passThru(),
                batchSize,
                executor);
        return concurrentMultimap;
    }

    public static <T, V> ObjectDoubleMap<V> sumByDouble(
            Iterable<T> iterable,
            Function<T, V> groupBy,
            DoubleFunction<? super T> function)
    {
        ObjectDoubleHashMap<V> result = ObjectDoubleHashMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByDoubleProcedure<>(groupBy, function),
                new SumByDoubleCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    public static <T, V> ObjectDoubleMap<V> sumByFloat(
            Iterable<T> iterable,
            Function<T, V> groupBy,
            FloatFunction<? super T> function)
    {
        ObjectDoubleHashMap<V> result = ObjectDoubleHashMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByFloatProcedure<>(groupBy, function),
                new SumByFloatCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    public static <T, V> ObjectLongMap<V> sumByLong(
            Iterable<T> iterable,
            Function<T, V> groupBy,
            LongFunction<? super T> function)
    {
        ObjectLongHashMap<V> result = ObjectLongHashMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByLongProcedure<>(groupBy, function),
                new SumByLongCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    public static <T, V> ObjectLongMap<V> sumByInt(
            Iterable<T> iterable,
            Function<T, V> groupBy,
            IntFunction<? super T> function)
    {
        ObjectLongHashMap<V> result = ObjectLongHashMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByIntProcedure<>(groupBy, function),
                new SumByIntCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    
Since:6.0
/**
     * @since 6.0
     */
    public static <V, T> MutableMap<V, BigDecimal> sumByBigDecimal(Iterable<T> iterable, Function<T, V> groupBy, Function<? super T, BigDecimal> function)
    {
        MutableMap<V, BigDecimal> result = UnifiedMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByBigDecimalProcedure<>(groupBy, function),
                new SumByBigDecimalCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    
Since:6.0
/**
     * @since 6.0
     */
    public static <V, T> MutableMap<V, BigInteger> sumByBigInteger(Iterable<T> iterable, Function<T, V> groupBy, Function<? super T, BigInteger> function)
    {
        MutableMap<V, BigInteger> result = UnifiedMap.newMap();
        ParallelIterate.forEach(
                iterable,
                new SumByBigIntegerProcedure<>(groupBy, function),
                new SumByBigIntegerCombiner<>(result),
                ParallelIterate.DEFAULT_MIN_FORK_SIZE,
                ParallelIterate.EXECUTOR_SERVICE);
        return result;
    }

    
Returns a brand new ExecutorService using the specified poolName with the specified maximum thread pool size. The
same poolName may be used more than once resulting in multiple pools with the same name.


The pool will be initialised with newPoolSize threads.  If that number of threads are in use and another thread
is requested, the pool will reject execution and the submitting thread will execute the task.

/**
     * Returns a brand new ExecutorService using the specified poolName with the specified maximum thread pool size. The
     * same poolName may be used more than once resulting in multiple pools with the same name.
     * <p>
     * The pool will be initialised with newPoolSize threads.  If that number of threads are in use and another thread
     * is requested, the pool will reject execution and the submitting thread will execute the task.
     */
    public static ExecutorService newPooledExecutor(int newPoolSize, String poolName, boolean useDaemonThreads)
    {
        return new ThreadPoolExecutor(
                newPoolSize,
                newPoolSize,
                0L,
                TimeUnit.MILLISECONDS,
                new SynchronousQueue<>(),
                new CollectionsThreadFactory(poolName, useDaemonThreads),
                new ThreadPoolExecutor.CallerRunsPolicy());
    }

    
Returns a brand new ExecutorService using the specified poolName and uses the optional property named
to set the maximum thread pool size.  The same poolName may be used more than
once resulting in multiple pools with the same name.

/**
     * Returns a brand new ExecutorService using the specified poolName and uses the optional property named
     * to set the maximum thread pool size.  The same poolName may be used more than
     * once resulting in multiple pools with the same name.
     */
    public static ExecutorService newPooledExecutor(String poolName, boolean useDaemonThreads)
    {
        return ParallelIterate.newPooledExecutor(ParallelIterate.getDefaultMaxThreadPoolSize(), poolName, useDaemonThreads);
    }

    public static int getDefaultTaskCount()
    {
        return ParallelIterate.getDefaultMaxThreadPoolSize() * ParallelIterate.getTaskRatio();
    }

    public static int getDefaultMaxThreadPoolSize()
    {
        return Math.min(AVAILABLE_PROCESSORS + 1, 100);
    }

    public static int getTaskRatio()
    {
        return TASK_RATIO;
    }

    private static final class SumByDoubleProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByDoubleProcedure<T, V>>
    {
        private final MutableMap<V, DoubleDoublePair> map = Maps.mutable.of();
        private final Function<T, V> groupBy;
        private final DoubleFunction<? super T> function;

        private SumByDoubleProcedure(Function<T, V> groupBy, DoubleFunction<? super T> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            V groupKey = this.groupBy.valueOf(each);
            DoubleDoublePair sumCompensation = this.map.getIfAbsentPut(groupKey, () -> PrimitiveTuples.pair(0.0d, 0.0d));
            double sum = sumCompensation.getOne();
            double compensation = sumCompensation.getTwo();
            double adjustedValue = this.function.doubleValueOf(each) - compensation;
            double nextSum = sum + adjustedValue;
            compensation = nextSum - sum - adjustedValue;
            sum = nextSum;
            this.map.put(groupKey, PrimitiveTuples.pair(sum, compensation));
        }

        public MutableMap<V, DoubleDoublePair> getResult()
        {
            return this.map;
        }

        @Override
        public SumByDoubleProcedure<T, V> create()
        {
            return new SumByDoubleProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByDoubleCombiner<T, V> extends AbstractProcedureCombiner<SumByDoubleProcedure<T, V>>
    {
        private final ObjectDoubleHashMap<V> result;
        private final ObjectDoubleHashMap<V> compensation = ObjectDoubleHashMap.newMap();

        private SumByDoubleCombiner(ObjectDoubleHashMap<V> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByDoubleProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                thingToCombine.getResult().forEachKeyValue((each, sumCompensation) -> {
                    this.result.put(each, sumCompensation.getOne());
                    this.compensation.put(each, sumCompensation.getTwo());
                });
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue((each, sumCompensation) -> {
                    double sum = this.result.get(each);
                    double currentCompensation = this.compensation.getIfAbsentPut(each, () -> 0.0d) + sumCompensation.getTwo();

                    double adjustedValue = sumCompensation.getOne() - currentCompensation;
                    double nextSum = sum + adjustedValue;
                    this.compensation.put(each, nextSum - sum - adjustedValue);
                    this.result.put(each, nextSum);
                });
            }
        }
    }

    private static final class SumByFloatProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByFloatProcedure<T, V>>
    {
        private final MutableMap<V, DoubleDoublePair> map = Maps.mutable.of();
        private final Function<T, V> groupBy;
        private final FloatFunction<? super T> function;

        private SumByFloatProcedure(Function<T, V> groupBy, FloatFunction<? super T> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            V groupKey = this.groupBy.valueOf(each);
            DoubleDoublePair sumCompensation = this.map.getIfAbsentPut(groupKey, () -> PrimitiveTuples.pair(0.0d, 0.0d));
            double sum = sumCompensation.getOne();
            double compensation = sumCompensation.getTwo();
            double adjustedValue = this.function.floatValueOf(each) - compensation;
            double nextSum = sum + adjustedValue;
            compensation = nextSum - sum - adjustedValue;
            sum = nextSum;
            this.map.put(groupKey, PrimitiveTuples.pair(sum, compensation));
        }

        public MutableMap<V, DoubleDoublePair> getResult()
        {
            return this.map;
        }

        @Override
        public SumByFloatProcedure<T, V> create()
        {
            return new SumByFloatProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByFloatCombiner<T, V> extends AbstractProcedureCombiner<SumByFloatProcedure<T, V>>
    {
        private final ObjectDoubleHashMap<V> result;
        private final ObjectDoubleHashMap<V> compensation = ObjectDoubleHashMap.newMap();

        private SumByFloatCombiner(ObjectDoubleHashMap<V> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByFloatProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                thingToCombine.getResult().forEachKeyValue((each, sumCompensation) -> {
                    this.result.put(each, sumCompensation.getOne());
                    this.compensation.put(each, sumCompensation.getTwo());
                });
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue((each, sumCompensation) -> {
                    double sum = this.result.get(each);
                    double currentCompensation = this.compensation.getIfAbsentPut(each, () -> 0.0d) + sumCompensation.getTwo();

                    double adjustedValue = sumCompensation.getOne() - currentCompensation;
                    double nextSum = sum + adjustedValue;
                    this.compensation.put(each, nextSum - sum - adjustedValue);
                    this.result.put(each, nextSum);
                });
            }
        }
    }

    private static final class SumByLongProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByLongProcedure<T, V>>
    {
        private final ObjectLongHashMap<V> map = ObjectLongHashMap.newMap();
        private final Function<T, V> groupBy;
        private final LongFunction<? super T> function;

        private SumByLongProcedure(Function<T, V> groupBy, LongFunction<? super T> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            this.map.addToValue(this.groupBy.valueOf(each), this.function.longValueOf(each));
        }

        public ObjectLongHashMap<V> getResult()
        {
            return this.map;
        }

        @Override
        public SumByLongProcedure<T, V> create()
        {
            return new SumByLongProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByLongCombiner<T, V> extends AbstractProcedureCombiner<SumByLongProcedure<T, V>>
    {
        private final ObjectLongHashMap<V> result;

        private SumByLongCombiner(ObjectLongHashMap<V> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByLongProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                this.result.putAll(thingToCombine.getResult());
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue(this.result::addToValue);
            }
        }
    }

    private static final class SumByIntProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByIntProcedure<T, V>>
    {
        private final ObjectLongHashMap<V> map = ObjectLongHashMap.newMap();
        private final Function<T, V> groupBy;
        private final IntFunction<? super T> function;

        private SumByIntProcedure(Function<T, V> groupBy, IntFunction<? super T> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            this.map.addToValue(this.groupBy.valueOf(each), (long) this.function.intValueOf(each));
        }

        public ObjectLongHashMap<V> getResult()
        {
            return this.map;
        }

        @Override
        public SumByIntProcedure<T, V> create()
        {
            return new SumByIntProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByIntCombiner<T, V> extends AbstractProcedureCombiner<SumByIntProcedure<T, V>>
    {
        private final ObjectLongHashMap<V> result;

        private SumByIntCombiner(ObjectLongHashMap<V> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByIntProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                this.result.putAll(thingToCombine.getResult());
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue(this.result::addToValue);
            }
        }
    }

    private static final class SumByBigDecimalProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByBigDecimalProcedure<T, V>>
    {
        private final MutableMap<V, BigDecimal> map = UnifiedMap.newMap();
        private final Function<T, V> groupBy;
        private final Function<? super T, BigDecimal> function;

        private SumByBigDecimalProcedure(Function<T, V> groupBy, Function<? super T, BigDecimal> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            this.map.updateValue(this.groupBy.valueOf(each), Functions0.zeroBigDecimal(), original -> original.add(this.function.valueOf(each)));
        }

        public MutableMap<V, BigDecimal> getResult()
        {
            return this.map;
        }

        @Override
        public SumByBigDecimalProcedure<T, V> create()
        {
            return new SumByBigDecimalProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByBigDecimalCombiner<T, V> extends AbstractProcedureCombiner<SumByBigDecimalProcedure<T, V>>
    {
        private final MutableMap<V, BigDecimal> result;

        private SumByBigDecimalCombiner(MutableMap<V, BigDecimal> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByBigDecimalProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                this.result.putAll(thingToCombine.getResult());
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue((key, value) -> this.result.updateValue(key, Functions0.zeroBigDecimal(), original -> original.add(value)));
            }
        }
    }

    private static final class SumByBigIntegerProcedure<T, V> implements Procedure<T>, ProcedureFactory<SumByBigIntegerProcedure<T, V>>
    {
        private final MutableMap<V, BigInteger> map = UnifiedMap.newMap();
        private final Function<T, V> groupBy;
        private final Function<? super T, BigInteger> function;

        private SumByBigIntegerProcedure(Function<T, V> groupBy, Function<? super T, BigInteger> function)
        {
            this.groupBy = groupBy;
            this.function = function;
        }

        @Override
        public void value(T each)
        {
            this.map.updateValue(this.groupBy.valueOf(each), Functions0.zeroBigInteger(), original -> original.add(this.function.valueOf(each)));
        }

        public MutableMap<V, BigInteger> getResult()
        {
            return this.map;
        }

        @Override
        public SumByBigIntegerProcedure<T, V> create()
        {
            return new SumByBigIntegerProcedure<>(this.groupBy, this.function);
        }
    }

    private static final class SumByBigIntegerCombiner<T, V> extends AbstractProcedureCombiner<SumByBigIntegerProcedure<T, V>>
    {
        private final MutableMap<V, BigInteger> result;

        private SumByBigIntegerCombiner(MutableMap<V, BigInteger> result)
        {
            super(true);
            this.result = result;
        }

        @Override
        public void combineOne(SumByBigIntegerProcedure<T, V> thingToCombine)
        {
            if (this.result.isEmpty())
            {
                this.result.putAll(thingToCombine.getResult());
            }
            else
            {
                thingToCombine.getResult().forEachKeyValue((key, value) -> this.result.updateValue(key, Functions0.zeroBigInteger(), original -> original.add(value)));
            }
        }
    }
}