001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.util;
019    
020    import org.apache.commons.logging.Log;
021    import org.apache.commons.logging.LogFactory;
022    
023    import org.apache.hadoop.classification.InterfaceStability;
024    
025    @InterfaceStability.Evolving
026    public class ThreadUtil {
027      
028      private static final Log LOG = LogFactory.getLog(ThreadUtil.class);
029    
030      /**
031       * Cause the current thread to sleep as close as possible to the provided
032       * number of milliseconds. This method will log and ignore any
033       * {@link InterruptedException} encountered.
034       * 
035       * @param millis the number of milliseconds for the current thread to sleep
036       */
037      public static void sleepAtLeastIgnoreInterrupts(long millis) {
038        long start = Time.now();
039        while (Time.now() - start < millis) {
040          long timeToSleep = millis -
041              (Time.now() - start);
042          try {
043            Thread.sleep(timeToSleep);
044          } catch (InterruptedException ie) {
045            LOG.warn("interrupted while sleeping", ie);
046          }
047        }
048      }
049    }