/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.db.tests.api.write.request;

import java.util.concurrent.Semaphore;

import org.junit.Test;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.testing.base.ExistingDatabaseTest;
import org.simantics.layer0.Layer0;

/**
 * Checks that unexpected write callback failures do not crash the session and
 * that the write request results were correctly committed.
 * 
 * @author Tuukka Lehtonen
 */
public class WriteCallbackFailureTest extends ExistingDatabaseTest {

    private static final String AN_ENTITY = "An entity";
    Resource written;

	@Test
    public void testFailingWriteCallback() throws DatabaseException{
        final Semaphore sem = new Semaphore(0);

        getSession().asyncRequest(new WriteRequest() {
            @Override
            public void perform(WriteGraph graph) throws DatabaseException {
                Layer0 b = Layer0.getInstance(graph);
                Resource test = graph.newResource();
                graph.claim(test, b.InstanceOf, null, b.Entity);
                Resource name = graph.newResource();
                graph.claim(name, b.InstanceOf, null, b.String);
                graph.claimValue(name, AN_ENTITY);
                graph.claim(test, b.HasName, name);

                written = test;
            }
        }, parameter -> {
            try {
                throw new NullPointerException("intentional failure");
            } finally {
                sem.release();
            }
        });

        try {
            sem.acquire();
        } catch (InterruptedException e) {
            throw new DatabaseException(e);
        }

        // This will block until the previous request has finished.
        getSession().syncRequest(new WriteRequest() {
            @Override
            public void perform(WriteGraph graph) throws DatabaseException {
                Layer0 b = Layer0.getInstance(graph);
                // Ensure that the previously written data exists.
                assertTrue(graph.hasStatement(written, b.InstanceOf, b.Entity));
                Resource name = graph.getSingleObject(written, b.HasName);
                assertTrue(graph.hasStatement(name, b.InstanceOf, b.String));
                assertTrue(graph.hasStatement(written, b.HasName, name));
                Object value = graph.getValue(name);
                assertTrue(value.equals(AN_ENTITY));
            }
        });
    }

}