StateConsumer xref

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    1   /***
    2    *
    3    * Copyright 2004 Protique Ltd
    4    *
    5    * Licensed under the Apache License, Version 2.0 (the "License");
    6    * you may not use this file except in compliance with the License.
    7    * You may obtain a copy of the License at
    8    *
    9    * http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   **/
    18  package org.codehaus.activecluster.impl;
    19
    20  import org.apache.commons.logging.Log;
    21  import org.apache.commons.logging.LogFactory;
    22  import org.codehaus.activecluster.Node;
    23
    24  import javax.jms.Message;
    25  import javax.jms.MessageListener;
    26  import javax.jms.ObjectMessage;
    27
    28
    29  /***
    30   * A JMS MessageListener which processes inbound messages and
    31   * applies them to a StateService
    32   *
    33   * @version $Revision: 1.3 $
    34   */
    35  public class StateConsumer implements MessageListener {
    36
    37      private final static Log log = LogFactory.getLog(StateConsumer.class);
    38
    39      private StateService stateService;
    40
    41      public StateConsumer(StateService stateService) {
    42          if (stateService == null) {
    43              throw new IllegalArgumentException("Must specify a valid StateService implementation");
    44          }
    45          this.stateService = stateService;
    46      }
    47
    48      public void onMessage(Message message) {
    49          if (log.isDebugEnabled()) {
    50              log.debug("Received cluster data message!: " + message);
    51          }
    52
    53          if (message instanceof ObjectMessage) {
    54              ObjectMessage objectMessage = (ObjectMessage) message;
    55              try {
    56                  Node node = (Node) objectMessage.getObject();
    57                  String type = objectMessage.getJMSType();
    58                  if (type != null && type.equals("shutdown")) {
    59                      stateService.shutdown(node);
    60                  }
    61                  else {
    62                      stateService.keepAlive(node);
    63                  }
    64              }
    65              catch (Exception e) {
    66                  log.error("Could not extract node from message: " + e + ". Message: " + message, e);
    67              }
    68          }
    69          else {
    70              log.warn("Ignoring message: " + message);
    71          }
    72      }
    73  }