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.client;
  
  import java.io.IOException;
  
  import org.apache.activemq.transport.amqp.client.util.AsyncResult;
  import org.apache.qpid.proton.engine.Delivery;
  import org.apache.qpid.proton.engine.Endpoint;
  import org.apache.qpid.proton.engine.EndpointState;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import java.lang.invoke.MethodHandles;
  
  /**
   * Abstract base for all AmqpResource implementations to extend.
   * <p>
   * This abstract class wraps up the basic state management bits so that the concrete object don't have to reproduce it.
   * Provides hooks for the subclasses to initialize and shutdown.
   */
  public abstract class AmqpAbstractResource<E extends Endpoint> implements AmqpResource {
  
     private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
     protected AsyncResult openRequest;
     protected AsyncResult closeRequest;
  
     private AmqpValidator amqpStateInspector;
  
     private E endpoint;
  
     @Override
     public void open(AsyncResult request) {
        this.openRequest = request;
        doOpen();
        getEndpoint().setContext(this);
     }
  
     @Override
     public boolean isOpen() {
        return getEndpoint().getRemoteState() == EndpointState.ACTIVE;
     }
  
     @Override
     public void opened() {
        if (this.openRequest != null) {
           this.openRequest.onSuccess();
           this.openRequest = null;
        }
     }
  
     @Override
     public void detach(AsyncResult request) {
        // If already closed signal success or else the caller might never get notified.
        if (getEndpoint().getLocalState() == EndpointState.CLOSED || getEndpoint().getRemoteState() == EndpointState.CLOSED) {
  
           if (getEndpoint().getLocalState() != EndpointState.CLOSED) {
              doDetach();
              getEndpoint().free();
           }
  
           request.onSuccess();
        } else {
           this.closeRequest = request;
           doDetach();
        }
     }
  
     @Override
     public void close(AsyncResult request) {
        // If already closed signal success or else the caller might never get notified.
        if (getEndpoint().getLocalState() == EndpointState.CLOSED || getEndpoint().getRemoteState() == EndpointState.CLOSED) {
  
           if (getEndpoint().getLocalState() != EndpointState.CLOSED) {
              doClose();
              getEndpoint().free();
           }
  
           request.onSuccess();
        } else {
           this.closeRequest = request;
           doClose();
        }
     }
  
     @Override
     public boolean isClosed() {
        return getEndpoint().getLocalState() == EndpointState.CLOSED;
     }
  
     @Override
     public void closed() {
        getEndpoint().close();
        getEndpoint().free();
  
        if (this.closeRequest != null) {
           this.closeRequest.onSuccess();
           this.closeRequest = null;
        }
     }
  
     @Override
     public void failed() {
        failed(new Exception("Remote request failed."));
     }
  
     @Override
     public void failed(Exception cause) {
        if (openRequest != null) {
           if (endpoint != null) {
              // TODO: if this is a producer/consumer link then we may only be detached,
              // rather than fully closed, and should respond appropriately.
              endpoint.close();
           }
           openRequest.onFailure(cause);
           openRequest = null;
        }
  
        if (closeRequest != null) {
           closeRequest.onFailure(cause);
           closeRequest = null;
        }
     }
  
     @Override
     public void remotelyClosed(AmqpConnection connection) {
        Exception error = AmqpSupport.convertToException(getEndpoint().getRemoteCondition());
  
        if (endpoint != null) {
           // TODO: if this is a producer/consumer link then we may only be detached,
           // rather than fully closed, and should respond appropriately.
           endpoint.close();
        }
  
        logger.info("Resource {} was remotely closed", this);
  
        connection.fireClientException(error);
     }
  
     @Override
     public void locallyClosed(AmqpConnection connection, Exception error) {
        if (endpoint != null) {
           // TODO: if this is a producer/consumer link then we may only be detached,
           // rather than fully closed, and should respond appropriately.
           endpoint.close();
        }
  
        logger.info("Resource {} was locally closed", this);
  
        connection.fireClientException(error);
     }
  
     public E getEndpoint() {
        return this.endpoint;
     }
  
     public void setEndpoint(E endpoint) {
        this.endpoint = endpoint;
     }
  
     public AmqpValidator getStateInspector() {
        return amqpStateInspector;
     }
  
     public void setStateInspector(AmqpValidator stateInspector) {
        if (stateInspector == null) {
           stateInspector = new AmqpValidator();
        }
  
        this.amqpStateInspector = stateInspector;
     }
  
     public EndpointState getLocalState() {
        if (getEndpoint() == null) {
           return EndpointState.UNINITIALIZED;
        }
        return getEndpoint().getLocalState();
     }
  
     public EndpointState getRemoteState() {
        if (getEndpoint() == null) {
           return EndpointState.UNINITIALIZED;
        }
        return getEndpoint().getRemoteState();
     }
  
     public boolean hasRemoteError() {
        return getEndpoint().getRemoteCondition().getCondition() != null;
     }
  
     @Override
     public void processRemoteOpen(AmqpConnection connection) throws IOException {
        doOpenInspection();
        doOpenCompletion();
     }
  
     @Override
     public void processRemoteDetach(AmqpConnection connection) throws IOException {
        doDetachedInspection();
        if (isAwaitingClose()) {
           logger.debug("{} is now closed: ", this);
           closed();
        } else {
           remotelyClosed(connection);
        }
     }
  
     @Override
     public void processRemoteClose(AmqpConnection connection) throws IOException {
        doClosedInspection();
        if (isAwaitingClose()) {
           logger.debug("{} is now closed: ", this);
           closed();
        } else if (isAwaitingOpen()) {
           // Error on Open, create exception and signal failure.
           logger.warn("Open of {} failed: ", this);
           Exception openError;
           if (hasRemoteError()) {
              openError = AmqpSupport.convertToException(getEndpoint().getRemoteCondition());
           } else {
              openError = getOpenAbortException();
           }
  
           failed(openError);
        } else {
           remotelyClosed(connection);
        }
     }
  
     @Override
     public void processDeliveryUpdates(AmqpConnection connection, Delivery delivery) throws IOException {
     }
  
     @Override
     public void processFlowUpdates(AmqpConnection connection) throws IOException {
     }
  
     /**
      * Perform the open operation on the managed endpoint. A subclass may override this method to provide additional open
      * actions or configuration updates.
      */
     protected void doOpen() {
        getEndpoint().open();
     }
  
     /**
      * Perform the close operation on the managed endpoint. A subclass may override this method to provide additional
      * close actions or alter the standard close path such as endpoint detach etc.
      */
     protected void doClose() {
        getEndpoint().close();
     }
  
     /**
      * Perform the detach operation on the managed endpoint.
      * <p>
      * By default this method throws an UnsupportedOperationException, a subclass must implement this and do a detach if
      * its resource supports that.
      */
     protected void doDetach() {
        throw new UnsupportedOperationException("Endpoint cannot be detached.");
     }
  
     /**
      * Complete the open operation on the managed endpoint. A subclass may override this method to provide additional
      * verification actions or configuration updates.
      */
     protected void doOpenCompletion() {
        logger.debug("{} is now open: ", this);
        opened();
     }
  
     /**
      * When aborting the open operation, and there isn't an error condition, provided by the peer, the returned exception
      * will be used instead. A subclass may override this method to provide alternative behaviour.
      */
     protected Exception getOpenAbortException() {
        return new IOException("Open failed unexpectedly.");
     }
  
     protected abstract void doOpenInspection();
  
     protected abstract void doClosedInspection();
  
     protected void doDetachedInspection() {
     }
  
     // ----- Private implementation utility methods ---------------------------//
  
     private boolean isAwaitingOpen() {
        return this.openRequest != null;
     }
  
     private boolean isAwaitingClose() {
        return this.closeRequest != null;
     }
  }
  