metron-streaming/Metron-Common/src/main/java/org/apache/metron/configuration/ConfigurationManager.java

/**
 * 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.metron.configuration;



import java.io.File;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.configuration.CombinedConfiguration;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.DefaultConfigurationBuilder;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

/**
 * Configuration manager class which loads all 'config-definition.xml' files and
 * creates a Configuration object which holds all properties from the underlying
 * configuration resource
 */
public class ConfigurationManager {

  /** configuration definition file name. */
  private static String DEFAULT_CONFIG_DEFINITION_FILE_NAME = "config-definition.xml";

  /** Stores a map with the configuration for each path specified. */
  private static Map<String, Configuration> configurationsCache = new HashMap<String, Configuration>();

  /** The Constant LOGGER. */
  private static final Logger LOGGER = Logger
      .getLogger(ConfigurationManager.class);

  /**
   * Common method to load content of all configuration resources defined in
   * 'config-definition.xml'.
   * 
   * @param configDefFilePath
   *          the config def file path
   * @return Configuration
   */
  public static Configuration getConfiguration(String configDefFilePath) {
    if (configurationsCache.containsKey(configDefFilePath)) {
      return configurationsCache.get(configDefFilePath);
    }
    CombinedConfiguration configuration = null;
    synchronized (configurationsCache) {
      if (configurationsCache.containsKey(configDefFilePath)) {
        return configurationsCache.get(configDefFilePath);
      }
      DefaultConfigurationBuilder builder = new DefaultConfigurationBuilder();
      String fielPath = getConfigDefFilePath(configDefFilePath);
      LOGGER.info("loading from 'configDefFilePath' :" + fielPath);
      builder.setFile(new File(fielPath));
      try {
        configuration = builder.getConfiguration(true);
        configurationsCache.put(fielPath, configuration);
      } catch (ConfigurationException e) {
        LOGGER.info("Exception in loading property files.", e);
      }
    }
    return configuration;
  }

  /**
   * Removes the configuration created from a config definition file located at
   * 'configDefFilePath'.
   * 
   * @param configDefFilePath
   *          path to the config definition file
   */
  public static void clearConfiguration(String configDefFilePath) {
    configurationsCache.remove(configDefFilePath);
  }

  /**
   * Gets the configuration.
   * 
   * @return the configuration
   */
  public static Configuration getConfiguration() {
    return getConfiguration(null);
  }

  /**
   * Returns the 'config-definition.xml' file path. 1. If the param
   * 'configDefFilePath' has a valid value, returns configDefFilePath 2. If the
   * system property key 'configDefFilePath' has a valid value, returns the
   * value 3. By default, it returns the file name 'config-definition.xml'
   * 
   * @param configDefFilePath
   *          given input path to the config definition file
   * @return the config def file path
   */
  private static String getConfigDefFilePath(String configDefFilePath) {
    if (StringUtils.isNotEmpty(configDefFilePath)) {
      return configDefFilePath;
    }
    return DEFAULT_CONFIG_DEFINITION_FILE_NAME;
  }

  /**
   * The main method.
   * 
   * @param args
   *          the args
   * @throws InterruptedException
   *           the interrupted exception
   */
  public static void main(String[] args) throws InterruptedException {
    Configuration config = ConfigurationManager
        .getConfiguration("/Users/Sayi/Documents/config/config-definition-dpi.xml");
    System.out.println("elastic.search.cluster ="
        + config.getString("elastic.search.cluster"));
    Thread.sleep(10000);
    System.out.println("storm.topology.dpi.bolt.es-index.index.name ="
        + config.getString("storm.topology.dpi.bolt.es-index.index.name"));
  }

}