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 java.util.LinkedHashSet;
  import java.util.Set;
  
  import org.apache.activemq.transport.amqp.client.util.AsyncResult;
  import org.apache.activemq.transport.amqp.client.util.ClientFuture;
  import org.apache.activemq.transport.amqp.client.util.ClientFutureSynchronization;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import java.lang.invoke.MethodHandles;
  
  /**
   * Defines a context under which resources in a given session will operate inside transaction scoped boundaries.
   */
  public class AmqpTransactionContext {
  
     private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
     private final AmqpSession session;
     private final Set<AmqpReceiver> txReceivers = new LinkedHashSet<>();
  
     private AmqpTransactionCoordinator coordinator;
     private AmqpTransactionId transactionId;
  
     public AmqpTransactionContext(AmqpSession session) {
        this.session = session;
     }
  
     /**
      * Begins a new transaction scoped to the target session.
      *
      * @throws Exception if an error occurs while starting the transaction.
      */
     public void begin() throws Exception {
        if (transactionId != null) {
           throw new IOException("Begin called while a TX is still Active.");
        }
  
        final AmqpTransactionId txId = session.getConnection().getNextTransactionId();
        final ClientFuture request = new ClientFuture(new ClientFutureSynchronization() {
  
           @Override
           public void onPendingSuccess() {
              transactionId = txId;
           }
  
           @Override
           public void onPendingFailure(Throwable cause) {
              transactionId = null;
           }
        });
  
        logger.info("Attempting to Begin TX:[{}]", txId);
  
        session.getScheduler().execute(() -> {
           if (coordinator == null || coordinator.isClosed()) {
              logger.info("Creating new Coordinator for TX:[{}]", txId);
              coordinator = new AmqpTransactionCoordinator(session);
              coordinator.open(new AsyncResult() {
  
                 @Override
                 public void onSuccess() {
                    try {
                       logger.info("Attempting to declare TX:[{}]", txId);
                       coordinator.declare(txId, request);
                    } catch (Exception e) {
                       request.onFailure(e);
                    }
                 }
  
                 @Override
                 public void onFailure(Throwable result) {
                    request.onFailure(result);
                 }
  
                 @Override
                 public boolean isComplete() {
                    return request.isComplete();
                 }
              });
           } else {
              try {
                 logger.info("Attempting to declare TX:[{}]", txId);
                 coordinator.declare(txId, request);
              } catch (Exception e) {
                 request.onFailure(e);
              }
           }
  
           session.pumpToProtonTransport(request);
        });
  
        request.sync();
     }
  
     /**
      * Commit this transaction which then ends the lifetime of the transacted operation.
      *
      * @throws Exception if an error occurs while performing the commit
      */
     public void commit() throws Exception {
        if (transactionId == null) {
           throw new IllegalStateException("Commit called with no active Transaction.");
        }
  
        preCommit();
  
        final ClientFuture request = new ClientFuture(new ClientFutureSynchronization() {
  
           @Override
           public void onPendingSuccess() {
              transactionId = null;
              postCommit();
           }
  
           @Override
           public void onPendingFailure(Throwable cause) {
              transactionId = null;
              postCommit();
           }
        });
  
        logger.debug("Commit on TX[{}] initiated", transactionId);
        session.getScheduler().execute(() -> {
           try {
              logger.info("Attempting to commit TX:[{}]", transactionId);
              coordinator.discharge(transactionId, request, true);
              session.pumpToProtonTransport(request);
           } catch (Exception e) {
              request.onFailure(e);
           }
        });
  
        request.sync();
     }
  
     /**
      * Rollback any transacted work performed under the current transaction.
      *
      * @throws Exception if an error occurs during the rollback operation.
      */
     public void rollback() throws Exception {
        if (transactionId == null) {
           throw new IllegalStateException("Rollback called with no active Transaction.");
        }
  
        preRollback();
  
        final ClientFuture request = new ClientFuture(new ClientFutureSynchronization() {
  
           @Override
           public void onPendingSuccess() {
              transactionId = null;
              postRollback();
           }
  
           @Override
           public void onPendingFailure(Throwable cause) {
              transactionId = null;
              postRollback();
           }
        });
  
        logger.debug("Rollback on TX[{}] initiated", transactionId);
        session.getScheduler().execute(() -> {
           try {
              logger.info("Attempting to roll back TX:[{}]", transactionId);
              coordinator.discharge(transactionId, request, false);
              session.pumpToProtonTransport(request);
           } catch (Exception e) {
              request.onFailure(e);
           }
        });
  
        request.sync();
     }
  
     //----- Internal access to context properties ----------------------------//
  
     public AmqpTransactionCoordinator getCoordinator() {
        return coordinator;
     }
  
     AmqpTransactionId getTransactionId() {
        return transactionId;
     }
  
     boolean isInTransaction() {
        return transactionId != null;
     }
  
     void registerTxConsumer(AmqpReceiver consumer) {
        txReceivers.add(consumer);
     }
  
     //----- Transaction pre / post completion --------------------------------//
  
     private void preCommit() {
        for (AmqpReceiver receiver : txReceivers) {
           receiver.preCommit();
        }
     }
  
     private void preRollback() {
        for (AmqpReceiver receiver : txReceivers) {
           receiver.preRollback();
        }
     }
  
     private void postCommit() {
        for (AmqpReceiver receiver : txReceivers) {
           receiver.postCommit();
        }
  
        txReceivers.clear();
     }
  
     private void postRollback() {
        for (AmqpReceiver receiver : txReceivers) {
           receiver.postRollback();
        }
  
        txReceivers.clear();
     }
  }
  