content: /*
   * 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.ambari.server.controller;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Properties;
  
  import org.apache.ambari.server.configuration.Configuration;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.inject.Inject;
  import com.google.inject.Singleton;
  
  /**
   * Stores the mapping of hostnames to be used in any configuration on 
   * the server.
   *  
   */
  @Singleton
  public class HostsMap {
    private final static Logger LOG = LoggerFactory
        .getLogger(HostsMap.class);
  
    private String hostsMapFile;
    private Properties hostsMap;
  
    @Inject
    public HostsMap(Configuration conf) {
      hostsMapFile = conf.getHostsMapFile();
      setupMap();
    }
    
    public HostsMap(String file) {
      hostsMapFile = file;
    }
  
    public void setupMap() {
      InputStream inputStream = null;
      LOG.info("Using hostsmap file " + this.hostsMapFile);
      try {
        if (hostsMapFile != null) {
          hostsMap = new Properties();
          inputStream = new FileInputStream(new File(hostsMapFile));
          // load the properties
          hostsMap.load(inputStream);
        }
      } catch (FileNotFoundException fnf) {
        LOG.info("No configuration file " + hostsMapFile + " found in classpath.", fnf);
      } catch (IOException ie) {
        throw new IllegalArgumentException("Can't read configuration file " +
            hostsMapFile, ie);
      } finally {
        if (inputStream != null) {
          try {
            inputStream.close();
          } catch(IOException io) {
            //ignore 
          }
        }
      }
    }
  
  /**
   * Return map of the hostname if available
   * @param hostName hostname map
   * @return 
   */
  public String getHostMap(String hostName) {
    if (hostsMapFile == null) 
      return hostName;
    return hostsMap.getProperty(hostName, hostName);
  }
  
  }
  