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.examples.group.bgd.utils;
020
021import org.apache.reef.driver.task.TaskConfiguration;
022import org.apache.reef.driver.task.TaskConfigurationOptions;
023import org.apache.reef.examples.group.bgd.MasterTask;
024import org.apache.reef.tang.*;
025import org.apache.reef.tang.annotations.Name;
026import org.apache.reef.tang.exceptions.InjectionException;
027
028import java.util.logging.Level;
029import java.util.logging.Logger;
030
031/**
032 * Subconfiguration: limit given configuration to a given list of classes.
033 */
034public final class SubConfiguration {
035
036  private static final Logger LOG = Logger.getLogger(SubConfiguration.class.getName());
037
038  @SafeVarargs
039  public static Configuration from(
040      final Configuration baseConf, final Class<? extends Name<?>>... classes) {
041
042    final Injector injector = Tang.Factory.getTang().newInjector(baseConf);
043    final JavaConfigurationBuilder confBuilder = Tang.Factory.getTang().newConfigurationBuilder();
044
045    for (final Class<? extends Name<?>> clazz : classes) {
046      try {
047        confBuilder.bindNamedParameter(clazz,
048            injector.getNamedInstance((Class<? extends Name<Object>>) clazz).toString());
049      } catch (final InjectionException ex) {
050        final String msg = "Exception while creating subconfiguration";
051        LOG.log(Level.WARNING, msg, ex);
052        throw new RuntimeException(msg, ex);
053      }
054    }
055
056    return confBuilder.build();
057  }
058
059  public static void main(final String[] args) throws InjectionException {
060
061    final Configuration conf = TaskConfiguration.CONF
062        .set(TaskConfiguration.IDENTIFIER, "TASK")
063        .set(TaskConfiguration.TASK, MasterTask.class)
064        .build();
065
066    final Configuration subConf = SubConfiguration.from(conf, TaskConfigurationOptions.Identifier.class);
067    LOG.log(Level.INFO, "OUT: Base conf:\n{0}", Configurations.toString(conf));
068    LOG.log(Level.INFO, "OUT: Sub conf:\n{0}", Configurations.toString(subConf));
069  }
070
071  /**
072   * Empty private constructor to prohibit instantiation of utility class.
073   */
074  private SubConfiguration() {
075  }
076}