/*
* This file is part of NucleusFramework for Bukkit, licensed under the MIT License (MIT).
*
* Copyright (c) JCThePants (www.jcwhatever.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.jcwhatever.nucleus.collections.wrap;
import java.util.Collection;
import java.util.List;
import java.util.ListIterator;
import java.util.concurrent.locks.ReadWriteLock;
/**
* An abstract implementation of a synchronized {@link List} wrapper. The wrapper is
* optionally synchronized via a sync object or {@link ReadWriteLock} passed into the
* constructor using a {@link SyncStrategy}.
*
* <p>If the list is synchronized, the sync object must be externally locked while
* the iterator is in use. Otherwise, a {@link java.lang.IllegalStateException} will
* be thrown.</p>
*
* <p>The actual collection is provided to the abstract implementation by
* overriding and returning it from the {@link #list} method.</p>
*
* <p>In order to make using the wrapper as an extension of a collection easier,
* several protected methods are provided for optional override. These methods
* are provided by the superclass {@link CollectionWrapper}.
*/
public abstract class ListWrapper<E> extends CollectionWrapper<E> implements List<E> {
/**
* Constructor.
*
* <p>No synchronization.</p>
*/
public ListWrapper() {
this(SyncStrategy.NONE);
}
/**
* Constructor.
*
* @param strategy The synchronization strategy to use.
*/
public ListWrapper(SyncStrategy strategy) {
super(strategy);
}
/**
* Invoked from a synchronized block to get the encapsulated list.
*/
protected abstract List<E> list();
@Override
protected Collection<E> collection() {
return list();
}
@Override
public boolean addAll(int index, Collection<? extends E> c) {
if (_lock != null) {
_lock.writeLock().lock();
try {
return addAllSource(index, c);
}
finally {
_lock.writeLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return addAllSource(index, c);
}
} else {
return addAllSource(index, c);
}
}
private boolean addAllSource(int index, Collection<? extends E> c) {
boolean isChanged = false;
for (E element : c) {
if (!onPreAdd(element))
continue;
add(index, element);
onAdded(element);
isChanged = true;
}
return isChanged;
}
@Override
public E get(int index) {
if (_lock != null) {
_lock.readLock().lock();
try {
return list().get(index);
}
finally {
_lock.readLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return list().get(index);
}
} else {
return list().get(index);
}
}
@Override
public E set(int index, E element) {
if (_lock != null) {
_lock.writeLock().lock();
try {
return setSource(index, element);
}
finally {
_lock.writeLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return setSource(index, element);
}
} else {
return setSource(index, element);
}
}
private E setSource(int index, E element) {
E previous = list().set(index, element);
onRemoved(previous);
onAdded(element);
return previous;
}
@Override
public void add(int index, E element) {
if (_lock != null) {
_lock.writeLock().lock();
try {
addSource(index, element);
}
finally {
_lock.writeLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
addSource(index, element);
}
} else {
addSource(index, element);
}
}
private void addSource(int index, E element) {
list().add(index, element);
onAdded(element);
}
@Override
public E remove(int index) {
if (_lock != null) {
_lock.writeLock().lock();
try {
return removeSource(index);
}
finally {
_lock.writeLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return removeSource(index);
}
} else {
return removeSource(index);
}
}
private E removeSource(int index) {
E removed = list().remove(index);
onRemoved(removed);
return removed;
}
@Override
public int indexOf(Object o) {
if (_lock != null) {
_lock.readLock().lock();
try {
return list().indexOf(o);
}
finally {
_lock.readLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return list().indexOf(o);
}
} else {
return list().indexOf(o);
}
}
@Override
public int lastIndexOf(Object o) {
if (_lock != null) {
_lock.readLock().lock();
try {
return list().lastIndexOf(o);
}
finally {
_lock.readLock().unlock();
}
}
else if (_sync != null) {
synchronized (_sync) {
return list().lastIndexOf(o);
}
} else {
return list().lastIndexOf(o);
}
}
@Override
public ListIterator<E> listIterator() {
return listIterator(0);
}
@Override
public ListIterator<E> listIterator(final int index) {
return new ListIteratorWrapper<E>(_strategy) {
ListIterator<E> iterator = list().listIterator(index);
@Override
protected boolean onRemove(E element) {
if (onPreRemove(element)) {
onRemoved(element);
return true;
}
return false;
}
@Override
protected ListIterator<E> iterator() {
return iterator;
}
};
}
@Override
public List<E> subList(int fromIndex, int toIndex) {
final List<E> subList = list().subList(fromIndex, toIndex);
final ListWrapper<E> parent = this;
return new ListWrapper<E>(_strategy) {
@Override
protected boolean onPreAdd(E element) {
return parent.onPreAdd(element);
}
@Override
protected void onAdded(E element) {
parent.onAdded(element);
}
@Override
protected boolean onPreRemove(Object obj) {
return parent.onPreRemove(obj);
}
@Override
protected void onRemoved(Object obj) {
parent.onRemoved(obj);
}
@Override
protected void onPreClear() {
parent.onPreClear();
}
@Override
protected void onClear(Collection<E> cleared) {
parent.onClear(cleared);
}
@Override
protected List<E> list() {
return subList;
}
};
}
}