content: /**
   * 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.activemq.transport.amqp.protocol;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.activemq.command.Command;
  import org.apache.qpid.proton.amqp.transport.ErrorCondition;
  import org.apache.qpid.proton.engine.Link;
  import org.apache.qpid.proton.engine.Sender;
  
  /**
   * Abstract AmqpLink implementation that provide basic Link services.
   */
  public abstract class AmqpAbstractLink<LINK_TYPE extends Link> implements AmqpLink {
  
      protected final AmqpSession session;
      protected final LINK_TYPE endpoint;
  
      protected boolean closed;
      protected boolean opened;
      protected List<Runnable> closeActions = new ArrayList<Runnable>();
  
      /**
       * Creates a new AmqpLink type.
       *
       * @param session
       *        the AmqpSession that servers as the parent of this Link.
       * @param endpoint
       *        the link endpoint this object represents.
       */
      public AmqpAbstractLink(AmqpSession session, LINK_TYPE endpoint) {
          this.session = session;
          this.endpoint = endpoint;
      }
  
      @Override
      public void open() {
          if (!opened) {
              getEndpoint().setContext(this);
              getEndpoint().open();
  
              opened = true;
          }
      }
  
      @Override
      public void detach() {
          if (!closed) {
              if (getEndpoint() != null) {
                  getEndpoint().setContext(null);
                  getEndpoint().detach();
                  getEndpoint().free();
              }
          }
      }
  
      @Override
      public void close(ErrorCondition error) {
          if (!closed) {
  
              if (getEndpoint() != null) {
                  if (getEndpoint() instanceof Sender) {
                      getEndpoint().setSource(null);
                  } else {
                      getEndpoint().setTarget(null);
                  }
                  getEndpoint().setCondition(error);
              }
  
              close();
          }
      }
  
      @Override
      public void close() {
          if (!closed) {
  
              if (getEndpoint() != null) {
                  getEndpoint().setContext(null);
                  getEndpoint().close();
                  getEndpoint().free();
              }
  
              for (Runnable action : closeActions) {
                  action.run();
              }
  
              closeActions.clear();
              opened = false;
              closed = true;
          }
      }
  
      /**
       * @return true if this link has already been opened.
       */
      public boolean isOpened() {
          return opened;
      }
  
      /**
       * @return true if this link has already been closed.
       */
      public boolean isClosed() {
          return closed;
      }
  
      /**
       * @return the Proton Link type this link represents.
       */
      public LINK_TYPE getEndpoint() {
          return endpoint;
      }
  
      /**
       * @return the parent AmqpSession for this Link instance.
       */
      public AmqpSession getSession() {
          return session;
      }
  
      @Override
      public void addCloseAction(Runnable action) {
          closeActions.add(action);
      }
  
      /**
       * Shortcut method to hand off an ActiveMQ Command to the broker and assign
       * a ResponseHandler to deal with any reply from the broker.
       *
       * @param command
       *        the Command object to send to the Broker.
       */
      protected void sendToActiveMQ(Command command) {
          session.getConnection().sendToActiveMQ(command, null);
      }
  
      /**
       * Shortcut method to hand off an ActiveMQ Command to the broker and assign
       * a ResponseHandler to deal with any reply from the broker.
       *
       * @param command
       *        the Command object to send to the Broker.
       * @param handler
       *        the ResponseHandler that will handle the Broker's response.
       */
      protected void sendToActiveMQ(Command command, ResponseHandler handler) {
          session.getConnection().sendToActiveMQ(command, handler);
      }
  }
  