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.camel.component.zookeeper.operations;
  
  import java.util.Set;
  import java.util.concurrent.CopyOnWriteArraySet;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  import org.apache.zookeeper.ZooKeeper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * <code>ZooKeeperOperation</code> is the base class for wrapping various ZooKeeper API instructions and callbacks into
   * callable and composable operation objects.
   */
  public abstract class ZooKeeperOperation<ResultType> {
  
      protected static final Logger LOG = LoggerFactory.getLogger(ZooKeeperOperation.class);
  
      protected static final Class<?>[] CONSTRUCTOR_ARGS = { ZooKeeper.class, String.class };
  
      protected String node;
  
      protected ZooKeeper connection;
  
      protected Set<Thread> waitingThreads = new CopyOnWriteArraySet<>();
  
      protected OperationResult<ResultType> result;
  
      private boolean producesExchange;
  
      private boolean cancelled;
  
      public ZooKeeperOperation(ZooKeeper connection, String node) {
          this(connection, node, true);
      }
  
      public ZooKeeperOperation(ZooKeeper connection, String node, boolean producesExchange) {
          this.connection = connection;
          this.node = node;
          this.producesExchange = producesExchange;
      }
  
      /**
       * Gets the result of this zookeeper operation, i.e. some data and the associated node stats
       */
      public abstract OperationResult<ResultType> getResult();
  
      public OperationResult<ResultType> get() throws InterruptedException, ExecutionException {
          waitingThreads.add(Thread.currentThread());
          result = getResult();
          return result;
      }
  
      public OperationResult<ResultType> get(long timeout, TimeUnit unit)
              throws InterruptedException, ExecutionException, TimeoutException {
          // TODO perhaps set a timer here
          return get();
      }
  
      public boolean cancel(boolean mayInterruptIfRunning) {
          if (mayInterruptIfRunning) {
              for (Thread waiting : waitingThreads) {
                  waiting.interrupt();
              }
              cancelled = true;
          }
          return mayInterruptIfRunning;
      }
  
      public boolean isCancelled() {
          return cancelled;
      }
  
      public boolean isDone() {
          return result != null;
      }
  
      public String getNode() {
          return node;
      }
  
      public boolean shouldProduceExchange() {
          return producesExchange;
      }
  
      // TODO slightly different to a clone as it uses the constructor
      public ZooKeeperOperation<?> createCopy() throws Exception {
          return getClass().getConstructor(CONSTRUCTOR_ARGS).newInstance(connection, node);
      }
  }
  