ServiceSupport


1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one or more
4    * contributor license agreements.  See the NOTICE file distributed with
5    * this work for additional information regarding copyright ownership.
6    * The ASF licenses this file to You under the Apache License, Version 2.0
7    * (the "License"); you may not use this file except in compliance with
8    * the License.  You may obtain a copy of the License at
9    *
10   * http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.activemq.util;
19  
20  import java.util.concurrent.atomic.AtomicBoolean  ;
21  
22  import org.apache.activemq.Service;
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  
26  /**
27   * A helper class for working with services together with a useful base class for service implementations.
28   *  
29   * @version $Revision: 1.1 $
30   */
31  public abstract class ServiceSupport implements Service {
32      private static final Log log = LogFactory.getLog(ServiceSupport.class);
33  
34      private AtomicBoolean   started = new AtomicBoolean  (false);
35      private AtomicBoolean   stopping = new AtomicBoolean  (false);
36      private AtomicBoolean   stopped = new AtomicBoolean  (false);
37  
38      public static void dispose(Service service) {
39          try {
40              service.stop();
41          }
42          catch (Exception   e) {
43              log.debug("Could not stop service: " + service + ". Reason: " + e, e);
44          }
45      }
46  
47      public void start() throws Exception   {
48          if (started.compareAndSet(false, true)) {
49              doStart();
50          }
51      }
52  
53      public void stop() throws Exception   {
54          if (stopped.compareAndSet(false, true)) {
55              stopping.set(true);
56              ServiceStopper stopper = new ServiceStopper();
57              try {
58                  doStop(stopper);
59              }
60              catch (Exception   e) {
61                  stopper.onException(this, e);
62              }
63              stopped.set(true);
64              started.set(false);
65              stopping.set(false);
66              stopper.throwFirstException();
67          }
68      }
69  
70      /**
71       * @return true if this service has been started
72       */
73      public boolean isStarted() {
74          return started.get();
75      }
76  
77      /**
78       * @return true if this service is in the process of closing
79       */
80      public boolean isStopping() {
81          return stopping.get();
82      }
83  
84      
85      /**
86       * @return true if this service is closed
87       */
88      public boolean isStopped() {
89          return stopped.get();
90      }
91  
92      protected abstract void doStop(ServiceStopper stopper) throws Exception  ;
93  
94      protected abstract void doStart() throws Exception  ;
95  }
96
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags