javolution.util.internal.collection.SharedCollectionImpl Maven / Gradle / Ivy
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/*
* Javolution - Java(TM) Solution for Real-Time and Embedded Systems
* Copyright (C) 2012 - Javolution (http://javolution.org/)
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software is
* freely granted, provided that this notice is preserved.
*/
package javolution.util.internal.collection;
import java.util.Collection;
import java.util.Iterator;
import javolution.util.function.Consumer;
import javolution.util.function.Equality;
import javolution.util.service.CollectionService;
/**
* A shared view over a collection (reads-write locks).
*/
public class SharedCollectionImpl extends CollectionView {
/** Thread-Safe Iterator. */
private class IteratorImpl implements Iterator { // Thread-Safe.
private E next;
private final Iterator targetIterator;
public IteratorImpl() {
lock.readLock.lock();
try {
targetIterator = cloneTarget().iterator(); // Copy.
} finally {
lock.readLock.unlock();
}
}
@Override
public boolean hasNext() {
return targetIterator.hasNext();
}
@Override
public E next() {
next = targetIterator.next();
return next;
}
@Override
public void remove() {
if (next == null) throw new IllegalStateException();
SharedCollectionImpl.this.remove(next);
next = null;
}
}
private static final long serialVersionUID = 0x600L; // Version.
protected ReadWriteLockImpl lock;
public SharedCollectionImpl(CollectionService target) {
this(target, new ReadWriteLockImpl());
}
public SharedCollectionImpl(CollectionService target,
ReadWriteLockImpl lock) {
super(target);
this.lock = lock;
}
@Override
public boolean add(E element) {
lock.writeLock.lock();
try {
return target().add(element);
} finally {
lock.writeLock.unlock();
}
}
@Override
public boolean addAll(Collection c) {
lock.writeLock.lock();
try {
return target().addAll(c);
} finally {
lock.writeLock.unlock();
}
}
@Override
public void clear() {
lock.writeLock.lock();
try {
target().clear();
} finally {
lock.writeLock.unlock();
}
}
@Override
public SharedCollectionImpl clone() {
lock.readLock.lock();
try {
SharedCollectionImpl copy = (SharedCollectionImpl) super
.clone();
copy.lock = new ReadWriteLockImpl(); // No need to share the same lock.
return copy;
} finally {
lock.readLock.unlock();
}
}
@Override
public Equality comparator() {
return target().comparator();
}
@Override
public boolean contains(Object o) {
lock.readLock.lock();
try {
return target().contains(o);
} finally {
lock.readLock.unlock();
}
}
@Override
public boolean containsAll(Collection c) {
lock.readLock.lock();
try {
return target().containsAll(c);
} finally {
lock.readLock.unlock();
}
}
@Override
public boolean equals(Object o) {
lock.readLock.lock();
try {
return target().equals(o);
} finally {
lock.readLock.unlock();
}
}
@Override
public int hashCode() {
lock.readLock.lock();
try {
return target().hashCode();
} finally {
lock.readLock.unlock();
}
}
@Override
public boolean isEmpty() {
lock.readLock.lock();
try {
return target().isEmpty();
} finally {
lock.readLock.unlock();
}
}
@Override
public Iterator iterator() {
return new IteratorImpl();
}
@Override
public void perform(Consumer> action,
CollectionService view) {
lock.readLock.lock();
try {
target().perform(action, view);
} finally {
lock.readLock.unlock();
}
}
@Override
public boolean remove(Object o) {
lock.writeLock.lock();
try {
return target().remove(o);
} finally {
lock.writeLock.unlock();
}
}
@Override
public boolean removeAll(Collection c) {
lock.writeLock.lock();
try {
return target().removeAll(c);
} finally {
lock.writeLock.unlock();
}
}
@Override
public boolean retainAll(Collection c) {
lock.writeLock.lock();
try {
return target().retainAll(c);
} finally {
lock.writeLock.unlock();
}
}
@Override
public int size() {
lock.readLock.lock();
try {
return target().size();
} finally {
lock.readLock.unlock();
}
}
@SuppressWarnings("unchecked")
@Override
public CollectionService[] split(int n) { // Shares the same locks.
CollectionService[] tmp;
lock.readLock.lock();
try {
tmp = target().split(n);
} finally {
lock.readLock.unlock();
}
CollectionService[] result = new CollectionService[tmp.length];
for (int i = 0; i < tmp.length; i++) {
result[i] = new SharedCollectionImpl(tmp[i], lock);
}
return result;
}
@Override
public CollectionService threadSafe() {
return this;
}
@Override
public Object[] toArray() {
lock.readLock.lock();
try {
return target().toArray();
} finally {
lock.readLock.unlock();
}
}
@Override
public T[] toArray(T[] a) {
lock.readLock.lock();
try {
return target().toArray(a);
} finally {
lock.readLock.unlock();
}
}
/** Returns a clone copy of target. */
protected CollectionService cloneTarget() {
try {
return target().clone();
} catch (CloneNotSupportedException e) {
throw new Error("Cannot happen since target is Cloneable.");
}
}
}