package org.simantics.db.tests.api.delayedWrite;

import java.util.concurrent.atomic.AtomicReference;

import org.junit.Assert;
import org.junit.Test;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.DelayedWriteRequest;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.exception.CancelTransactionException;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.testing.annotation.Fails;
import org.simantics.db.testing.base.ExistingDatabaseTest;

/**
 * Checks that throwing CancelTransactionException from within
 * {@link DelayedWriteRequest#perform(WriteGraph)} will
 * <ol>
 * <li>Cancel the transaction correctly without getting stuck</li>
 * <li>Write no data into the database</li>
 * </ol>
 * 
 * @author Tuukka Lehtonen
 */
public class DelayedWriteRequestCancelHandling extends ExistingDatabaseTest {

    @Test
    @Fails
    public void test() throws Exception {
        final AtomicReference<Resource> ref = new AtomicReference<Resource>();
        try {
            DelayedWriteRequest r = new DelayedWriteRequest() {
                @Override
                public void perform(WriteGraph graph) throws DatabaseException {
                    // Should throw an exception / error
                    ref.set(graph.newResource());
                    graph.claim(ref.get(), L0.InstanceOf, null, L0.String);
                    throw new CancelTransactionException("intentional cancel");
                }
            };
            getSession().sync(r);
        } catch (CancelTransactionException e) {
            // Should happen.
        } catch (DatabaseException e) {
            // Shouldn't happen.
            fail("Got DatabaseException " + e + ", should've received CancelTransactionException");
        }

        // Just to check the database session is still alive.
        Resource r = getSession().sync(new org.simantics.db.common.primitiverequest.Resource("http:/"));

        fail("No data should've been written", getSession().sync(new UniqueRead<Boolean>() {
            @Override
            public Boolean perform(ReadGraph graph) throws DatabaseException {
                return graph.hasStatement( ref.get() );
            }
        }));
    }

}