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.distributedlog.lock;
  
  import java.io.IOException;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.TimeUnit;
  import org.apache.bookkeeper.common.concurrent.FutureUtils;
  import org.apache.bookkeeper.common.util.OrderedScheduler;
  import org.apache.distributedlog.exceptions.DLInterruptedException;
  import org.apache.distributedlog.util.Utils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Lock waiter represents the attempt that application tries to lock.
   */
  public class LockWaiter {
  
      private static final Logger logger = LoggerFactory.getLogger(LockWaiter.class);
  
      private final String lockId;
      private final String currentOwner;
      private final CompletableFuture<Boolean> acquireFuture;
  
      public LockWaiter(String lockId,
                        String currentOwner,
                        CompletableFuture<Boolean> acquireFuture) {
          this.lockId = lockId;
          this.currentOwner = currentOwner;
          this.acquireFuture = acquireFuture;
      }
  
      /**
       * Return the lock id of the waiter.
       *
       * @return lock id of the waiter
       */
      public String getId() {
          return lockId;
      }
  
      /**
       * Return the owner that observed when waiter is waiting.
       *
       * @return the owner that observed when waiter is waiting
       */
      public String getCurrentOwner() {
          return currentOwner;
      }
  
      /**
       * Return the future representing the waiting result.
       *
       * <p>If the future is interrupted
       * (e.g. {@link FutureUtils#within(CompletableFuture, long, TimeUnit, Throwable, OrderedScheduler, Object)}),
       * the waiter will automatically clean up its waiting state.
       *
       * @return the future representing the acquire result.
       */
      public CompletableFuture<Boolean> getAcquireFuture() {
          return acquireFuture;
      }
  
      /**
       * Wait for the acquire result.
       *
       * @return true if acquired successfully, otherwise false.
       */
      public boolean waitForAcquireQuietly() {
          boolean success = false;
          try {
              success = Utils.ioResult(acquireFuture);
          } catch (DLInterruptedException ie) {
              Thread.currentThread().interrupt();
          } catch (LockTimeoutException lte) {
              logger.debug("Timeout on lock acquiring", lte);
          } catch (IOException e) {
              logger.error("Caught exception waiting for lock acquired", e);
          }
          return success;
      }
  
  }
  