001/*
002 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
003 *
004 * Project and contact information: http://www.cascading.org/
005 *
006 * This file is part of the Cascading project.
007 *
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 *     http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 */
020
021package cascading.flow.hadoop;
022
023import cascading.property.ConfigDef;
024import org.apache.hadoop.conf.Configuration;
025
026/**
027*
028*/
029public class ConfigurationSetter implements ConfigDef.Setter
030  {
031  private final Configuration conf;
032
033  public ConfigurationSetter( Configuration conf )
034    {
035    this.conf = conf;
036    }
037
038  @Override
039  public String set( String key, String value )
040    {
041    String oldValue = get( key );
042
043    conf.set( key, value );
044
045    return oldValue;
046    }
047
048  @Override
049  public String update( String key, String value )
050    {
051    String oldValue = get( key );
052
053    if( oldValue == null )
054      conf.set( key, value );
055    else if( !oldValue.contains( value ) )
056      conf.set( key, oldValue + "," + value );
057
058    return oldValue;
059    }
060
061  @Override
062  public String get( String key )
063    {
064    String value = conf.get( key );
065
066    if( value == null || value.isEmpty() )
067      return null;
068
069    return value;
070    }
071  }