LazyKeyChecker.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2012, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.jboss.capedwarf.datastore;

import java.util.concurrent.atomic.AtomicBoolean;

import javax.transaction.Status;

import com.google.appengine.api.datastore.Key;

/**
 * @author <a href="mailto:ales.justin@jboss.org">Ales Justin</a>
 */
public abstract class LazyKeyChecker {
    private final AtomicBoolean checked = new AtomicBoolean();
    protected final Key ancestor;
    protected final boolean inTx;

    protected LazyKeyChecker(Key ancestor, boolean inTx) {
        this.ancestor = ancestor;
        this.inTx = inTx;
    }

    protected void check() {
        if (inTx) {
            if (CapedwarfTransaction.getTxStatus() != Status.STATUS_ACTIVE) {
                throw new IllegalStateException("Transaction with which this operation is associated is not active.");
            }

            if (checked.compareAndSet(false, true)) {
                EntityGroupTracker.trackKey(ancestor);
            }
        }
    }
}