test.utils/src/main/java/org/apache/clerezza/test/utils/LockableMGraphWrapperForTesting.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor  license  agreements.  See the NOTICE file distributed
 * with this work  for  additional  information  regarding  copyright
 * ownership.  The ASF  licenses  this file to you 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 org.apache.clerezza.test.utils;

import org.apache.clerezza.*;

import java.util.Iterator;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * Wrappes an Graph as a LockableGraph. If a method is called that reads
 * or modifies the wrapped graph and the appropriate lock is not set, then a
 * RuntimeException is thrown.
 *
 * @author rbn, mir
 */
public class LockableMGraphWrapperForTesting extends GraphWrapper {

    private final ReentrantReadWriteLock lock = (ReentrantReadWriteLock) getLock();
    private final Lock readLock = lock.readLock();
    private final Graph wrapped;

    /**
     * Constructs a LocalbleGraph for an Graph.
     *
     * @param providedGraph a non-lockable mgraph
     */
    public LockableMGraphWrapperForTesting(final Graph providedGraph) {
        super(providedGraph);
        this.wrapped = providedGraph;
    }

    @Override
    public Iterator<Triple> filter(BlankNodeOrIRI subject, IRI predicate, RDFTerm object) {
        LockChecker.checkIfReadLocked(lock);
        readLock.lock();
        try {
            return new LockingIteratorForTesting(wrapped.filter(subject, predicate, object), lock);
        } finally {
            readLock.unlock();
        }
    }

    @Override
    public Iterator<Triple> iterator() {
        LockChecker.checkIfReadLocked(lock);
        readLock.lock();
        try {
            return new LockingIteratorForTesting(wrapped.iterator(), lock);
        } finally {
            readLock.unlock();
        }
    }

}