/*
* Copyright (c) 2018 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.utility.internal;
import java.lang.reflect.Constructor;
import java.lang.reflect.Proxy;
import java.util.Collection;
import java.util.PriorityQueue;
import java.util.Set;
import java.util.SortedSet;
import java.util.concurrent.PriorityBlockingQueue;
import org.eclipse.collections.api.collection.MutableCollection;
import org.eclipse.collections.api.factory.Lists;
import org.eclipse.collections.api.factory.Sets;
public class DefaultSpeciesNewStrategy
{
public static final DefaultSpeciesNewStrategy INSTANCE = new DefaultSpeciesNewStrategy();
private static final Class<?>[] SIZE_CONSTRUCTOR_TYPES = {int.class};
// todo - Consider behaviour for adapters, eg.:
// - SetAdapter.adapt(new TreeSet(orderingComparator))
// - SetAdapter.adapt(hibernateCollectionProxy)
Creates a new instance of a collection based on the class type of collection, not on the type of objects the collections contains. e.g. CollectionFactory.<Integer>speciesNew(hashSetOfString)
returns a new HashSet<Integer>()
; e.g. CollectionFactory.<Date>speciesNew(linkedListOfWombles)
returns a new LinkedList<Date>()
; /**
* Creates a new instance of a collection based on the class type of collection, not on the type of objects the collections contains.
* e.g. {@code CollectionFactory.<Integer>speciesNew(hashSetOfString)} returns a new {@code HashSet<Integer>()};
* e.g. {@code CollectionFactory.<Date>speciesNew(linkedListOfWombles)} returns a new {@code LinkedList<Date>()};
*/
public <T> Collection<T> speciesNew(Collection<?> collection)
{
if (collection instanceof MutableCollection)
{
return ((MutableCollection<T>) collection).newEmpty();
}
if (collection instanceof Proxy)
{
return DefaultSpeciesNewStrategy.createNewInstanceForCollectionType(collection);
}
if (ReflectionHelper.hasDefaultConstructor(collection.getClass()))
{
return (Collection<T>) ReflectionHelper.newInstance(collection.getClass());
}
return DefaultSpeciesNewStrategy.createNewInstanceForCollectionType(collection);
}
Creates a new instance of a collection based on the class type of collection and specified initial capacity, not on the type of objects the collections contains. e.g. CollectionFactory.<Integer>speciesNew(hashSetOfString, 20)
returns a new HashSet<Integer>(20)
; e.g. CollectionFactory.<Date>speciesNew(linkedListOfWombles, 42)
returns a new LinkedList<Date>(42)
; /**
* Creates a new instance of a collection based on the class type of collection and specified initial capacity,
* not on the type of objects the collections contains.
* e.g. {@code CollectionFactory.<Integer>speciesNew(hashSetOfString, 20)} returns a new {@code HashSet<Integer>(20)};
* e.g. {@code CollectionFactory.<Date>speciesNew(linkedListOfWombles, 42)} returns a new {@code LinkedList<Date>(42)};
*/
public <T> Collection<T> speciesNew(Collection<?> collection, int size)
{
if (size < 0)
{
throw new IllegalArgumentException("size may not be < 0 but was " + size);
}
if (collection instanceof Proxy
|| collection instanceof PriorityQueue
|| collection instanceof PriorityBlockingQueue
|| collection instanceof SortedSet)
{
return DefaultSpeciesNewStrategy.createNewInstanceForCollectionType(collection);
}
Constructor<?> constructor = ReflectionHelper.getConstructor(collection.getClass(), SIZE_CONSTRUCTOR_TYPES);
if (constructor != null)
{
return (Collection<T>) ReflectionHelper.newInstance(constructor, size);
}
return this.speciesNew(collection);
}
private static <T> Collection<T> createNewInstanceForCollectionType(Collection<?> collection)
{
if (collection instanceof SortedSet
|| collection instanceof PriorityQueue
|| collection instanceof PriorityBlockingQueue)
{
return Lists.mutable.empty();
}
if (collection instanceof Set)
{
return Sets.mutable.empty();
}
return Lists.mutable.empty();
}
}