/* * Copyright 2005-2010 the original author or authors. * * Licensed 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.wamblee.wicket.transactions; import java.util.logging.Level; import java.util.logging.Logger; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.transaction.Status; import javax.transaction.UserTransaction; import org.apache.wicket.Application; import org.apache.wicket.Page; import org.apache.wicket.Response; import org.apache.wicket.protocol.http.WebApplication; import org.apache.wicket.protocol.http.WebRequest; import org.apache.wicket.protocol.http.WebRequestCycle; /** *

* This class provides an Open Transaction in View implementation for * wicket. It provides a custom request cycle that uses the * {@link UserTransaction} to make sure that all work is done within a single * transaction. In Hibernate context, this is referred to as open session in * view. *

* *

* The method used by this class is more correctly called * Open Transaction in View and has a similar effect to open session in * view. It is however more general because it supports any (JTA) transactional * resource. Also it is more efficient/scalable than most open session in view * implementations because a database connection is only obtained from the * connection pool when it is needed. *

* *

* To use this request cycle, add it in your wicket {@link Application} subclass * by overriding * {@link Application#newRequestCycle(org.apache.wicket.Request, Response)}. For * example: *

* *
 * @Override
 * public RequestCycle newRequestCycle(Request aRequest, Response aResponse) {
 *     return new OpenTransactionInViewRequestCycle(this, (WebRequest) aRequest,
 *         aResponse);
 * }
 * 
* * @author Erik Brakkee * */ public class OpenTransactionInViewRequestCycle extends WebRequestCycle { private static final Logger LOG = Logger.getLogger(OpenTransactionInViewRequestCycle.class.getName()); private static final String JAVA_COMP_USER_TRANSACTION_JNDI = "java:comp/UserTransaction"; private UserTransaction userTransaction; /** * Constructs the request cycle. * * @param aApplication * Application to use. * @param aRequest * Request * @param aResponse * Response. */ public OpenTransactionInViewRequestCycle(final WebApplication aApplication, final WebRequest aRequest, final Response aResponse) { super(aApplication, aRequest, aResponse); userTransaction = getUserTransaction(); } @Override protected void onBeginRequest() { try { userTransaction.begin(); } catch (Exception e) { throw new RuntimeException("Could not start transaction", e); } super.onBeginRequest(); } @Override protected void onEndRequest() { try { if ( LOG.isLoggable(Level.FINEST)) { LOG.finest("Transaction status: " + userTransaction.getStatus()); } if (userTransaction.getStatus() == Status.STATUS_ACTIVE) { userTransaction.commit(); } else if (userTransaction.getStatus() == Status.STATUS_MARKED_ROLLBACK) { userTransaction.rollback(); } else { LOG.warning("Transaction status is '" + userTransaction.getStatus() + "' not committing or rolling back"); } } catch (Exception e) { throw new RuntimeException("Could not commit transaction", e); } super.onEndRequest(); } @Override public Page onRuntimeException(Page aPage, RuntimeException aE) { super.onEndRequest(); try { userTransaction.rollback(); } catch (Exception e) { throw new RuntimeException("Could not rollback transaction", e); } return super.onRuntimeException(aPage, aE); } private UserTransaction getUserTransaction() { try { InitialContext ctx = new InitialContext(); return (UserTransaction) ctx .lookup(JAVA_COMP_USER_TRANSACTION_JNDI); } catch (NamingException e) { throw new RuntimeException( "Could not obtain user transaction object"); } } }