hadoop ConfigHelper 源码

haddop ConfigHelper 代码

文件路径：/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-applications/hadoop-yarn-services/hadoop-yarn-services-core/src/main/java/org/apache/hadoop/yarn/service/utils/ConfigHelper.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.hadoop.yarn.service.utils;

import org.apache.hadoop.util.Preconditions;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.yarn.service.exceptions.BadConfigException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.StringWriter;
import java.net.URL;
import java.util.Map;

/**
 * Methods to aid in config, both in the Configuration class and
 * with other parts of setting up Slider-initated processes.
 *
 * Some of the methods take an argument of a map iterable for their sources; this allows
 * the same method
 */
public class ConfigHelper {
  private static final Logger log = LoggerFactory.getLogger(ConfigHelper.class);

  /**
   * Set an entire map full of values
   *
   * @param config config to patch
   * @param map map of data
   * @param origin origin data
   */
  public static void addConfigMap(Configuration config,
                                  Map<String, String> map,
                                  String origin) throws BadConfigException {
    addConfigMap(config, map.entrySet(), origin);
  }

  /**
   * Set an entire map full of values
   *
   * @param config config to patch
   * @param map map of data
   * @param origin origin data
   */
  public static void addConfigMap(Configuration config,
                                  Iterable<Map.Entry<String, String>> map,
                                  String origin) throws BadConfigException {
    for (Map.Entry<String, String> mapEntry : map) {
      String key = mapEntry.getKey();
      String value = mapEntry.getValue();
      if (value == null) {
        throw new BadConfigException("Null value for property " + key);
      }
      config.set(key, value, origin);
    }
  }

  /**
   * Convert to an XML string
   * @param conf configuration
   * @return conf
   * @throws IOException
   */
  public static String toXml(Configuration conf) throws IOException {
    StringWriter writer = new StringWriter();
    conf.writeXml(writer);
    return writer.toString();
  }


  /**
   * Register a resource as a default resource.
   * Do not attempt to use this unless you understand that the
   * order in which default resources are loaded affects the outcome,
   * and that subclasses of Configuration often register new default
   * resources
   * @param resource the resource name
   * @return the URL or null
   */
  public static URL registerDefaultResource(String resource) {
    URL resURL = getResourceUrl(resource);
    if (resURL != null) {
      Configuration.addDefaultResource(resource);
    }
    return resURL;
  }

  /**
   * Load a configuration from a resource on this classpath.
   * If the resource is not found, an empty configuration is returned
   * @param resource the resource name
   * @return the loaded configuration.
   */
  public static Configuration loadFromResource(String resource) {
    Configuration conf = new Configuration(false);
    URL resURL = getResourceUrl(resource);
    if (resURL != null) {
      log.debug("loaded resources from {}", resURL);
      conf.addResource(resource);
    } else{
      log.debug("failed to find {} on the classpath", resource);
    }
    return conf;

  }

  /**
   * Get the URL to a resource, null if not on the CP
   * @param resource resource to look for
   * @return the URL or null
   */
  public static URL getResourceUrl(String resource) {
    return ConfigHelper.class.getClassLoader()
                                  .getResource(resource);
  }

  /**
   * This goes through the keyset of one configuration and retrieves each value
   * from a value source -a different or the same configuration. This triggers
   * the property resolution process of the value, resolving any variables against
   * in-config or inherited configurations
   * @param keysource source of keys
   * @param valuesource the source of values
   * @return a new configuration where <code>foreach key in keysource, get(key)==valuesource.get(key)</code>
   */
  public static Configuration resolveConfiguration(
      Iterable<Map.Entry<String, String>> keysource,
      Configuration valuesource) {
    Configuration result = new Configuration(false);
    for (Map.Entry<String, String> entry : keysource) {
      String key = entry.getKey();
      String value = valuesource.get(key);
      Preconditions.checkState(value != null,
          "no reference for \"%s\" in values", key);
      result.set(key, value);
    }
    return result;
  }

}

相关信息

hadoop 源码目录

相关文章

hadoop ApplicationReportSerDeser 源码

hadoop ClientRegistryBinder 源码

hadoop Comparators 源码

hadoop ConfigUtils 源码

hadoop CoreFileSystem 源码

hadoop Duration 源码

hadoop FilterUtils 源码

hadoop HttpUtil 源码

hadoop JsonSerDeser 源码

hadoop PatternValidator 源码