com.google.cloud.hadoop.util.ConfigurationUtil Maven / Gradle / Ivy

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/*
 * Copyright 2013 Google Inc. All Rights Reserved.
 * 
 * Licensed 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 com.google.cloud.hadoop.util;

import com.google.common.base.Joiner;
import com.google.common.base.Strings;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;

/**
 * Helpers for checking the validity of Hadoop configurations.
 */
public class ConfigurationUtil {
  /**
   * Gets value for the given key or throws if value is not found.
   */
  public static String getMandatoryConfig(Configuration config, String key)
      throws IOException {
    String value = config.get(key);
    if (Strings.isNullOrEmpty(value)) {
      throw new IOException("Must supply a value for configuration setting: " + key);
    }
    return value;
  }

  /**
   * Gets value for the given keys or throws if one or more values are not found.
   */
  public static Map getMandatoryConfig(
      Configuration config, List keys)
      throws IOException {
    List missingKeys = new ArrayList<>();
    Map values = new HashMap<>();
    for (String key : keys) {
      String value = config.get(key);
      if (Strings.isNullOrEmpty(value)) {
        missingKeys.add(key);
      } else {
        values.put(key, value);
      }
    }
    if (missingKeys.size() > 0) {
      Joiner joiner = Joiner.on(", ");
      String message = "Must supply value for configuration settings: " + joiner.join(missingKeys);
      throw new IOException(message);
    }
    return values;
  }
}