From 16aa82e4a7755e096585f24d3714790b535f91d2 Mon Sep 17 00:00:00 2001
From: Erik Brakkee <erik@brakkee.org>
Date: Sat, 17 Jul 2010 14:11:31 +0000
Subject: [PATCH]

---
 .../OpenTransactionInViewRequestCycle.java    | 142 ++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 wicket/joe/src/main/java/org/wamblee/wicket/transactions/OpenTransactionInViewRequestCycle.java

diff --git a/wicket/joe/src/main/java/org/wamblee/wicket/transactions/OpenTransactionInViewRequestCycle.java b/wicket/joe/src/main/java/org/wamblee/wicket/transactions/OpenTransactionInViewRequestCycle.java
new file mode 100644
index 00000000..2953aa07
--- /dev/null
+++ b/wicket/joe/src/main/java/org/wamblee/wicket/transactions/OpenTransactionInViewRequestCycle.java
@@ -0,0 +1,142 @@
+/*
+ * 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;
+
+/**
+ * <p>
+ * This class provides an <em>Open Transaction in View</em> 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.
+ * </p>
+ * 
+ * <p>
+ * The method used by this class is more correctly called
+ * <em>Open Transaction in View</em> 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.
+ * </p>
+ * 
+ * <p>
+ * 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:
+ * </p>
+ * 
+ * <pre>
+ * &#064;Override
+ * public RequestCycle newRequestCycle(Request aRequest, Response aResponse) {
+ *     return new OpenTransactionInViewRequestCycle(this, (WebRequest) aRequest,
+ *         aResponse);
+ * }
+ * </pre>
+ * 
+ * @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");
+        }
+    }
+}
-- 
2.31.1