hbase-common/src/main/java/org/apache/hadoop/hbase/util/IncrementingEnvironmentEdge.java

   1 /*
   2  *
   3  * Licensed to the Apache Software Foundation (ASF) under one
   4  * or more contributor license agreements.  See the NOTICE file
   5  * distributed with this work for additional information
   6  * regarding copyright ownership.  The ASF licenses this file
   7  * to you under the Apache License, Version 2.0 (the
   8  * "License"); you may not use this file except in compliance
   9  * with the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  */
  19 package org.apache.hadoop.hbase.util;
  20
  21 import org.apache.yetus.audience.InterfaceAudience;
  22
  23 /**
  24  * Uses an incrementing algorithm instead of the default.
  25  */
  26 @InterfaceAudience.Private
  27 public class IncrementingEnvironmentEdge implements EnvironmentEdge {
  28
  29   private long timeIncrement;
  30
  31   /**
  32    * Construct an incremental edge starting from currentTimeMillis
  33    */
  34   public IncrementingEnvironmentEdge() {
  35     this(System.currentTimeMillis());
  36   }
  37
  38   /**
  39    * Construct an incremental edge with an initial amount
  40    * @param initialAmount the initial value to start with
  41    */
  42   public IncrementingEnvironmentEdge(long initialAmount) {
  43     this.timeIncrement = initialAmount;
  44   }
  45
  46   /**
  47    * {@inheritDoc}
  48    * <p>
  49    * This method increments a known value for the current time each time this
  50    * method is called. The first value is 1.
  51    * </p>
  52    */
  53   @Override
  54   public synchronized long currentTime() {
  55     return timeIncrement++;
  56   }
  57
  58   /**
  59    * Increment the time by the given amount
  60    */
  61   public synchronized long incrementTime(long amount) {
  62     timeIncrement += amount;
  63     return timeIncrement;
  64   }
  65 }