001    /*
002     * JBoss DNA (http://www.jboss.org/dna)
003     * See the COPYRIGHT.txt file distributed with this work for information
004     * regarding copyright ownership.  Some portions may be licensed
005     * to Red Hat, Inc. under one or more contributor license agreements.
006     * See the AUTHORS.txt file in the distribution for a full listing of 
007     * individual contributors. 
008     *
009     * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
010     * is licensed to you under the terms of the GNU Lesser General Public License as
011     * published by the Free Software Foundation; either version 2.1 of
012     * the License, or (at your option) any later version.
013     *
014     * JBoss DNA is distributed in the hope that it will be useful,
015     * but WITHOUT ANY WARRANTY; without even the implied warranty of
016     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017     * Lesser General Public License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this software; if not, write to the Free
021     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
022     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
023     */
024    package org.jboss.dna.connector.federation;
025    
026    import java.util.concurrent.TimeUnit;
027    import java.util.concurrent.atomic.AtomicReference;
028    import javax.transaction.xa.XAResource;
029    import net.jcip.annotations.ThreadSafe;
030    import org.jboss.dna.graph.ExecutionContext;
031    import org.jboss.dna.graph.cache.CachePolicy;
032    import org.jboss.dna.graph.connector.RepositoryConnection;
033    import org.jboss.dna.graph.connector.RepositorySourceException;
034    import org.jboss.dna.graph.connector.RepositorySourceListener;
035    import org.jboss.dna.graph.request.Request;
036    import org.jboss.dna.graph.request.processor.RequestProcessor;
037    
038    /**
039     * @author Randall Hauch
040     */
041    @ThreadSafe
042    public class FederatedRepositoryConnection implements RepositoryConnection {
043    
044        protected static final RepositorySourceListener NO_OP_LISTENER = new RepositorySourceListener() {
045            public void notify( String sourceName,
046                                Object... events ) {
047                // do nothing
048            }
049        };
050    
051        private final FederatedRepository repository;
052        private final String sourceName;
053        private final AtomicReference<RepositorySourceListener> listener;
054    
055        protected FederatedRepositoryConnection( FederatedRepository repository,
056                                                 String sourceName ) {
057            assert sourceName != null;
058            assert repository != null;
059            this.sourceName = sourceName;
060            this.repository = repository;
061            this.listener = new AtomicReference<RepositorySourceListener>(NO_OP_LISTENER);
062            this.repository.register(this);
063        }
064    
065        /**
066         * @return repository
067         */
068        protected FederatedRepository getRepository() {
069            return this.repository;
070        }
071    
072        /**
073         * {@inheritDoc}
074         */
075        public String getSourceName() {
076            return this.sourceName;
077        }
078    
079        /**
080         * {@inheritDoc}
081         */
082        public CachePolicy getDefaultCachePolicy() {
083            return null;
084        }
085    
086        /**
087         * {@inheritDoc}
088         */
089        public XAResource getXAResource() {
090            return null;
091        }
092    
093        /**
094         * {@inheritDoc}
095         */
096        public void setListener( RepositorySourceListener listener ) {
097            if (listener == null) listener = NO_OP_LISTENER;
098            RepositorySourceListener oldListener = this.listener.getAndSet(listener);
099            this.repository.addListener(listener);
100            if (oldListener != NO_OP_LISTENER) {
101                this.repository.removeListener(oldListener);
102            }
103        }
104    
105        /**
106         * {@inheritDoc}
107         */
108        public boolean ping( long time,
109                             TimeUnit unit ) {
110            return this.repository.isRunning();
111        }
112    
113        /**
114         * {@inheritDoc}
115         * 
116         * @see org.jboss.dna.graph.connector.RepositoryConnection#execute(org.jboss.dna.graph.ExecutionContext,
117         *      org.jboss.dna.graph.request.Request)
118         */
119        public void execute( ExecutionContext context,
120                             Request request ) throws RepositorySourceException {
121            if (!this.repository.isRunning()) {
122                throw new RepositorySourceException(FederationI18n.repositoryHasBeenShutDown.text(this.repository.getName()));
123            }
124            if (request == null) return;
125    
126            RequestProcessor processor = this.repository.getProcessor(context, sourceName);
127            assert processor != null;
128            try {
129                processor.process(request);
130            } finally {
131                processor.close();
132            }
133        }
134    
135        /**
136         * {@inheritDoc}
137         */
138        public void close() {
139            try {
140                this.repository.removeListener(this.listener.get());
141            } finally {
142                this.repository.unregister(this);
143            }
144        }
145    
146    }