/*
 * Copyright (c) 2017 Goldman Sachs and others.
 * 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.list.immutable;

import java.io.IOException;
import java.io.Serializable;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.RandomAccess;

import org.eclipse.collections.api.bag.ImmutableBag;
import org.eclipse.collections.api.bag.MutableBagIterable;
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.DoubleObjectToDoubleFunction;
import org.eclipse.collections.api.block.function.primitive.IntObjectToIntFunction;
import org.eclipse.collections.api.block.function.primitive.LongObjectToLongFunction;
import org.eclipse.collections.api.block.predicate.Predicate;
import org.eclipse.collections.api.block.predicate.Predicate2;
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.factory.Bags;
import org.eclipse.collections.api.factory.Lists;
import org.eclipse.collections.api.factory.Stacks;
import org.eclipse.collections.api.list.ImmutableList;
import org.eclipse.collections.api.partition.list.PartitionImmutableList;
import org.eclipse.collections.api.stack.MutableStack;
import org.eclipse.collections.api.tuple.Pair;
import org.eclipse.collections.impl.partition.list.PartitionFastList;

This is a zero element ImmutableList which is created by calling the Lists.immutable.empty() method.
/** * This is a zero element {@link ImmutableList} which is created by calling the Lists.immutable.empty() method. */
final class ImmutableEmptyList<T> extends AbstractImmutableList<T> implements Serializable, RandomAccess { static final ImmutableList<?> INSTANCE = new ImmutableEmptyList<>(); private static final PartitionImmutableList<?> EMPTY = new PartitionFastList<>().toImmutable(); private static final long serialVersionUID = 1L; private Object readResolve() { return INSTANCE; } @Override public ImmutableList<T> newWithout(T element) { return this; } @Override public ImmutableList<T> newWithoutAll(Iterable<? extends T> elements) { return this; } @Override public int size() { return 0; } @Override public boolean contains(Object obj) { return false; } @Override public T get(int index) { throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + this.size()); } @Override public ImmutableList<T> tap(Procedure<? super T> procedure) { return this; } @Override public void each(Procedure<? super T> procedure) { } @Override public void reverseForEach(Procedure<? super T> procedure) { } @Override public void reverseForEachWithIndex(ObjectIntProcedure<? super T> procedure) { } @Override public void forEachWithIndex(ObjectIntProcedure<? super T> objectIntProcedure) { } @Override public <P> void forEachWith(Procedure2<? super T, ? super P> procedure, P parameter) { } @Override public ImmutableList<T> newWith(T newItem) { return Lists.immutable.with(newItem); } @Override public T min(Comparator<? super T> comparator) { throw new NoSuchElementException(); } @Override public T max(Comparator<? super T> comparator) { throw new NoSuchElementException(); } @Override public T min() { throw new NoSuchElementException(); } @Override public T max() { throw new NoSuchElementException(); } @Override public <V extends Comparable<? super V>> T minBy(Function<? super T, ? extends V> function) { throw new NoSuchElementException(); } @Override public <V extends Comparable<? super V>> T maxBy(Function<? super T, ? extends V> function) { throw new NoSuchElementException(); } @Override public <S> ImmutableList<Pair<T, S>> zip(Iterable<S> that) { return Lists.immutable.empty(); } @Override public <S, R extends Collection<Pair<T, S>>> R zip(Iterable<S> that, R target) { return target; } @Override public ImmutableList<Pair<T, Integer>> zipWithIndex() { return Lists.immutable.empty(); } @Override public MutableStack<T> toStack() { return Stacks.mutable.empty(); } @Override public <R extends Collection<Pair<T, Integer>>> R zipWithIndex(R target) { return target; } @Override public ImmutableList<T> select(Predicate<? super T> predicate) { return this; } @Override public <P, R extends Collection<T>> R selectWith(Predicate2<? super T, ? super P> predicate, P parameter, R target) { return target; } @Override public ImmutableList<T> reject(Predicate<? super T> predicate) { return this; } @Override public <P, R extends Collection<T>> R rejectWith(Predicate2<? super T, ? super P> predicate, P parameter, R target) { return target; } @Override public PartitionImmutableList<T> partition(Predicate<? super T> predicate) { return (PartitionImmutableList<T>) EMPTY; } @Override public <V> ImmutableList<V> collect(Function<? super T, ? extends V> function) { return Lists.immutable.empty(); } @Override public <V> ImmutableList<V> collectIf(Predicate<? super T> predicate, Function<? super T, ? extends V> function) { return Lists.immutable.empty(); } @Override public <P, V, R extends Collection<V>> R collectWith(Function2<? super T, ? super P, ? extends V> function, P parameter, R target) { return target; } @Override public <V> ImmutableList<V> flatCollect(Function<? super T, ? extends Iterable<V>> function) { return Lists.immutable.empty(); } @Override public <V, R extends Collection<V>> R flatCollect(Function<? super T, ? extends Iterable<V>> function, R targetCollection) { return targetCollection; }
Since:9.0
/** * @since 9.0 */
@Override public <V> ImmutableBag<V> countBy(Function<? super T, ? extends V> function) { return Bags.immutable.empty(); }
Since:9.0
/** * @since 9.0 */
@Override public <V, R extends MutableBagIterable<V>> R countBy(Function<? super T, ? extends V> function, R target) { return target; }
Since:9.0
/** * @since 9.0 */
@Override public <V, P> ImmutableBag<V> countByWith(Function2<? super T, ? super P, ? extends V> function, P parameter) { return Bags.immutable.empty(); }
Since:9.0
/** * @since 9.0 */
@Override public <V, P, R extends MutableBagIterable<V>> R countByWith(Function2<? super T, ? super P, ? extends V> function, P parameter, R target) { return target; }
Since:10.0.0
/** * @since 10.0.0 */
@Override public <V> ImmutableBag<V> countByEach(Function<? super T, ? extends Iterable<V>> function) { return Bags.immutable.empty(); }
Since:10.0.0
/** * @since 10.0.0 */
@Override public <V, R extends MutableBagIterable<V>> R countByEach(Function<? super T, ? extends Iterable<V>> function, R target) { return target; } @Override public T detect(Predicate<? super T> predicate) { return null; } @Override public Optional<T> detectOptional(Predicate<? super T> predicate) { return Optional.empty(); } @Override public int count(Predicate<? super T> predicate) { return 0; } @Override public <P> int countWith(Predicate2<? super T, ? super P> predicate, P parameter) { return 0; } @Override public boolean anySatisfy(Predicate<? super T> predicate) { return false; } @Override public boolean allSatisfy(Predicate<? super T> predicate) { return true; } @Override public boolean noneSatisfy(Predicate<? super T> predicate) { return true; } @Override public <P> boolean anySatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter) { return false; } @Override public <P> boolean allSatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter) { return true; } @Override public <P> boolean noneSatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter) { return true; } @Override public <IV> IV injectInto(IV injectedValue, Function2<? super IV, ? super T, ? extends IV> function) { return injectedValue; } @Override public int injectInto(int injectedValue, IntObjectToIntFunction<? super T> intObjectToIntFunction) { return injectedValue; } @Override public long injectInto(long injectedValue, LongObjectToLongFunction<? super T> longObjectToLongFunction) { return injectedValue; } @Override public double injectInto(double injectedValue, DoubleObjectToDoubleFunction<? super T> doubleObjectToDoubleFunction) { return injectedValue; } @Override public T getFirst() { return null; } @Override public T getLast() { return null; } @Override public T getOnly() { throw new IllegalStateException("Size must be 1 but was " + this.size()); } @Override public int indexOf(Object object) { return -1; } @Override public boolean equals(Object otherList) { if (otherList == this) { return true; } if (!(otherList instanceof List)) { return false; } List<T> list = (List<T>) otherList; return list.isEmpty(); } @Override public int hashCode() { return 1; } @Override public boolean isEmpty() { return true; } @Override public boolean notEmpty() { return false; } @Override public <R extends Collection<T>> R select(Predicate<? super T> predicate, R target) { return target; } @Override public <R extends Collection<T>> R reject(Predicate<? super T> predicate, R target) { return target; } @Override public <V, R extends Collection<V>> R collect(Function<? super T, ? extends V> function, R target) { return target; } @Override public <V, R extends Collection<V>> R collectIf(Predicate<? super T> predicate, Function<? super T, ? extends V> function, R target) { return target; } @Override public T detectIfNone(Predicate<? super T> predicate, Function0<? extends T> function) { return function.value(); } @Override public String toString() { return "[]"; } @Override public String makeString() { return ""; } @Override public String makeString(String separator) { return ""; } @Override public String makeString(String start, String separator, String end) { return start + end; } @Override public void appendString(Appendable appendable) { } @Override public void appendString(Appendable appendable, String separator) { } @Override public void appendString(Appendable appendable, String start, String separator, String end) { try { appendable.append(start); appendable.append(end); } catch (IOException e) { throw new RuntimeException(e); } } @Override public ImmutableList<T> take(int count) { if (count < 0) { throw new IllegalArgumentException("Count must be greater than zero, but was: " + count); } return this; } @Override public ImmutableList<T> takeWhile(Predicate<? super T> predicate) { return this; } @Override public ImmutableList<T> drop(int count) { if (count < 0) { throw new IllegalArgumentException("Count must be greater than zero, but was: " + count); } return this; } @Override public ImmutableList<T> dropWhile(Predicate<? super T> predicate) { return this; } @Override public PartitionImmutableList<T> partitionWhile(Predicate<? super T> predicate) { return (PartitionImmutableList<T>) EMPTY; } }