/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.locks.*;

/**
 * This is an incomplete implementation of a wrapper class
 * that places read-write locks around unsynchronized Collections.
 * Exists as a sample input for CollectionLoops test.
 */
public final class RWCollection<E> implements Collection<E> {
    private final Collection c;
    private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock();

    public RWCollection(Collection<E> c) {
        if (c == null)
            throw new NullPointerException();
        this.c = c;
    }

    public RWCollection() {
        this(new ArrayList<E>());
    }

    public final int size() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.size(); }
        finally { l.unlock(); }
    }

    public final boolean isEmpty() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.isEmpty(); }
        finally { l.unlock(); }
    }

    public final boolean contains(Object o) {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.contains(o); }
        finally { l.unlock(); }
    }

    public final boolean equals(Object o) {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.equals(o); }
        finally { l.unlock(); }
    }

    public final int hashCode() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.hashCode(); }
        finally { l.unlock(); }
    }

    public final String toString() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.toString(); }
        finally { l.unlock(); }
    }

    public final Iterator<E> iterator() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.iterator(); }
        finally { l.unlock(); }
    }

    public final Object[] toArray() {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return c.toArray(); }
        finally { l.unlock(); }
    }

    public final <T> T[] toArray(T[] a) {
        final ReentrantReadWriteLock.ReadLock l = rwl.readLock();
        l.lock();
        try { return (T[])c.toArray(a); }
        finally { l.unlock(); }
    }

    public final boolean add(E e) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.add(e); }
        finally { l.unlock(); }
    }

    public final boolean remove(Object o) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.remove(o); }
        finally { l.unlock(); }
    }

    public final boolean containsAll(Collection<?> coll) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.containsAll(coll); }
        finally { l.unlock(); }
    }

    public final boolean addAll(Collection<? extends E> coll) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.addAll(coll); }
        finally { l.unlock(); }
    }

    public final boolean removeAll(Collection<?> coll) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.removeAll(coll); }
        finally { l.unlock(); }
    }

    public final boolean retainAll(Collection<?> coll) {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { return c.retainAll(coll); }
        finally { l.unlock(); }
    }

    public final void clear() {
        final ReentrantReadWriteLock.WriteLock l = rwl.writeLock();
        l.lock();
        try { c.clear(); }
        finally { l.unlock(); }
    }

}