com.bah.culvert.util.ConfUtils.java Source code

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Here is the source code for com.bah.culvert.util.ConfUtils.java

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/**
 * Copyright 2011 Booz Allen Hamilton.
 * 
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership. Booz Allen Hamilton
 * 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 com.bah.culvert.util;

import java.util.Map.Entry;

import org.apache.hadoop.conf.Configuration;

public class ConfUtils {

    /**
     * Pack a configuration into a namespace in another one.
     * 
     * @param prefix The prefix to pack into. A '.' character is appended to the
     *        prefix.
     * @param toPack The configuration to pack.
     * @param toPackInto The configuration to pack <tt>toPack</tt> into.
     * @return <tt>toPackInto</tt>, with <tt>toPack</tt> packed in the prefix.
     */
    public static Configuration packConfigurationInPrefix(String prefix, Configuration toPack,
            Configuration toPackInto) {
        for (Entry<String, String> entry : toPack) {
            toPackInto.set(prefix + "." + entry.getKey(), entry.getValue());
        }
        return toPackInto;
    }

    /**
     * Unpack a configuration that has been prefixed. A '.' character must be used
     * to separate the prefixed keys from the prefix.
     * 
     * @param prefix The prefix to unpack.
     * @param toUnpackFrom The configuration to unpack from.
     * @return The unpacked configuration.
     */
    public static Configuration unpackConfigurationInPrefix(String prefix, Configuration toUnpackFrom) {
        Configuration conf = new Configuration(false);
        conf.clear();
        prefix += ".";
        for (Entry<String, String> entry : toUnpackFrom) {
            String key = entry.getKey();
            if (key.startsWith(prefix)) {
                key = key.substring(prefix.length());
                conf.set(key, entry.getValue());
            }
        }
        return conf;
    }

}