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.tang;
020
021import org.apache.reef.tang.formats.AvroConfigurationSerializer;
022import org.apache.reef.tang.formats.ConfigurationSerializer;
023
024/**
025 * Helper class for Configurations.
026 */
027public final class Configurations {
028
029  private static final AvroConfigurationSerializer SERIALIZER = new AvroConfigurationSerializer();
030
031  /**
032   * This is a utility class that isn't meant to be instantiated.
033   */
034  private Configurations() {
035  }
036
037  /**
038   * Merge a set of Configurations.
039   *
040   * @param configurations the configuration to be merged
041   * @return the merged configuration.
042   * @throws org.apache.reef.tang.exceptions.BindException if the merge fails.
043   */
044  public static Configuration merge(final Configuration... configurations) {
045    return Tang.Factory.getTang().newConfigurationBuilder(configurations).build();
046  }
047
048  /**
049   * Merge a set of Configurations.
050   *
051   * @param configurations the configuration to be merged
052   * @return the merged configuration.
053   * @throws org.apache.reef.tang.exceptions.BindException if the merge fails.
054   */
055  public static Configuration merge(final Iterable<Configuration> configurations) {
056    final ConfigurationBuilder configurationBuilder = Tang.Factory.getTang().newConfigurationBuilder();
057    for (final Configuration configuration : configurations) {
058      configurationBuilder.addConfiguration(configuration);
059    }
060    return configurationBuilder.build();
061  }
062
063  /**
064   * Get the default configuration serializer.
065   * Currently it is AvroConfigurationSerializer.
066   * Use Tang.toString(...) to produce a human-readable string representation of the config.
067   * @return configuration serializer object.
068   */
069  public static ConfigurationSerializer getDefaultSerializer() {
070    return SERIALIZER;
071  }
072
073  /**
074   * Return human-readable representation of the configuration.
075   * @param config input configuration.
076   * @return a string that contains human-readable representation of the input configuration.
077   */
078  public static String toString(final Configuration config) {
079    return SERIALIZER.toString(config);
080  }
081
082  /**
083   * Return human-readable representation of the configuration.
084   * If prettyPrint is true, try to produce a nicer text layout, if possible.
085   * @param config input configuration.
086   * @param prettyPrint if true, try to produce a nicer text layout, when possible.
087   * Otherwise, use the default options of the serializer.
088   * Default value is false as not all serializers and formats support pretty printing.
089   * @return a string that contains human-readable representation of the input configuration.
090   */
091  public static String toString(final Configuration config, final boolean prettyPrint) {
092    return SERIALIZER.toString(config, prettyPrint);
093  }
094}