/*
* Copyright 2015 Goldman Sachs.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.gs.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 com.gs.collections.api.collection.MutableCollection;
import com.gs.collections.impl.factory.Lists;
import com.gs.collections.impl.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>();
*/
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);
*/
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();
}
}