201305.mbox/raw/%3c20130528095052.0842D2388ACC@eris.apache.org%3e

+
+    /*
+     * Licensed to the Apache Software Foundation (ASF) under one
+     * or more contributor license agreements.  See the NOTICE file
+     * distributed with this work for additional information
+     * regarding copyright ownership.  The ASF licenses this file
+     * to you 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.apache.chemistry.opencmis.bridge.httpsession;
+
+    import java.util.Map;
+    import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+    import javax.servlet.http.HttpSession;
+
+    import org.apache.chemistry.opencmis.bridge.CachedBindingCmisService;
+    import org.apache.chemistry.opencmis.commons.spi.CmisBinding;
+
+    /**
+     * Uses HTTP sessions to cache {@link CmisBinding} objects.
+     */
+    public abstract class HttpSessionCmisService extends CachedBindingCmisService {
+
+        private static final long serialVersionUID = 1L;
+
+        /** Key in the HTTP session. **/
+        public static final String CMIS_BINDING = "org.apache.chemistry.opencmis.bridge.binding";
+
+        private ReentrantReadWriteLock lock;
+
+        public void init(Map<String, String> parameters, ReentrantReadWriteLock lock) {
+            init(parameters);
+            this.lock = lock;
+        }
+
+        @Override
+        public CmisBinding getCmisBindingFromCache() {
+            HttpSession httpSession = getHttpSession(false);
+            if (httpSession == null) {
+                return null;
+            }
+
+            lock.readLock().lock();
+            try {
+                return (CmisBinding) httpSession.getAttribute(CMIS_BINDING);
+            } finally {
+                lock.readLock().unlock();
+            }
+        }
+
+        @Override
+        public CmisBinding putCmisBindingIntoCache(CmisBinding binding) {
+            HttpSession httpSession = getHttpSession(true);
+
+            lock.writeLock().lock();
+            try {
+                CmisBinding existingBinding = (CmisBinding) httpSession.getAttribute(CMIS_BINDING);
+                if (existingBinding == null) {
+                    httpSession.setAttribute(CMIS_BINDING, binding);
+                } else {
+                    binding = existingBinding;
+                }
+
+                return binding;
+            } finally {
+                lock.writeLock().unlock();
+            }
+        }
+
+        /**
+         * Returns the current {@link HttpSession}.
+         *
+         * @param create
+         *            <code>true</code> to create a new session, <code>false</code>
+         *            to return <code>null</code> if there is no current session
+         */
+        public HttpSession getHttpSession(boolean create) {
+            return getHttpServletRequest().getSession(create);
+        }
+    }
+