Source code

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,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.io.checkpoint;
020
021import org.apache.commons.lang.RandomStringUtils;
022import org.apache.reef.tang.annotations.Name;
023import org.apache.reef.tang.annotations.NamedParameter;
024import org.apache.reef.tang.annotations.Parameter;
025
026import javax.inject.Inject;
027
028/**
029 * A naming service that generates a random checkpoint name by appending a random alphanumeric string (suffix)
030 * of a given length to a user-supplied prefix string.
031 */
032public class RandomNameCNS implements CheckpointNamingService {
033
034  private final String prefix;
035  private final int lengthOfRandomSuffix;
036
037  @Deprecated
038  public RandomNameCNS(@Parameter(PREFIX.class) final String prefix) {
039    this.prefix = prefix;
040    this.lengthOfRandomSuffix
041            = Integer.parseInt(LengthOfRandomSuffix.class.getAnnotation(NamedParameter.class).default_value());
042  }
043
044  @Inject
045  private RandomNameCNS(@Parameter(PREFIX.class) final String prefix,
046                        @Parameter(LengthOfRandomSuffix.class) final int lengthOfRandomSuffix) {
047    this.prefix = prefix;
048    this.lengthOfRandomSuffix = lengthOfRandomSuffix;
049  }
050
051  @Override
052  public String getNewName() {
053    return this.prefix + RandomStringUtils.randomAlphanumeric(lengthOfRandomSuffix);
054  }
055
056  /**
057   * The prefix used for the random names returned.
058   */
059  @NamedParameter(doc = "The prefix used for the random names returned.", default_value = "checkpoint_")
060  public static class PREFIX implements Name<String> {
061  }
062
063  /**
064   * Number of alphanumeric characters in the random part of a checkpoint name.
065   */
066  @NamedParameter(doc = "Number of alphanumeric chars in the random part of a checkpoint name.", default_value = "8")
067  public static class LengthOfRandomSuffix implements Name<Integer> {
068  }
069
070}