/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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 org.apache.hadoop.fi;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.HdfsConfiguration;

/**
 * This class wraps the logic around fault injection configuration file
 * Default file is expected to be found in src/test/fi-site.xml
 * This default file should be copied by JUnit Ant's tasks to 
 * build/test/extraconf folder before tests are ran
 * An alternative location can be set through
 *   -Dfi.config=<file_name>
 */
public class FiConfig {
  private static final String CONFIG_PARAMETER = ProbabilityModel.FPROB_NAME + "config";
  private static final String DEFAULT_CONFIG = "fi-site.xml";
  private static Configuration conf;
  static {
    init();
  }
  
  protected static void init () {
    if (conf == null) {
      conf = new HdfsConfiguration(false);
      String configName = System.getProperty(CONFIG_PARAMETER, DEFAULT_CONFIG);
      conf.addResource(configName);
    }
  }
  
  /**
   * Method provides access to local Configuration 
   * 
   * @return Configuration initialized with fault injection's parameters
   */
  public static Configuration getConfig() {
    return conf;
  }
}