/*
    * 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.giraph.conf;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.log4j.Logger;
  
  import com.google.common.base.Objects;
  import com.google.common.collect.ComparisonChain;
  
  /**
   * Abstract base class of configuration options
   */
  public abstract class AbstractConfOption
      implements Comparable<AbstractConfOption> {
    /** Logger */
    private static final Logger LOG = Logger.getLogger(AbstractConfOption.class);
  
    /** Key for configuration */
    private final String key;
  
    /** Configuration option description */
    private final String description;
  
    /**
     * Constructor
     *
     * @param key configuration key
     * @param description configuration description
     */
    public AbstractConfOption(String key, String description) {
      this.key = key;
      this.description = description;
    }
  
    public String getKey() {
      return key;
    }
  
    /**
     * @return the description
     */
    public String getDescription() {
      return description;
    }
  
    /**
     * Check if option is set in configuration
     *
     * @param conf Configuration
     * @return true if option is set
     */
    public boolean contains(Configuration conf) {
      return conf.get(key) != null;
    }
  
    @Override public int compareTo(AbstractConfOption o) {
      return ComparisonChain.start()
        .compare(getType(), o.getType())
        .compare(key, o.key)
        .result();
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (!(o instanceof AbstractConfOption)) {
        return false;
      }
  
      AbstractConfOption that = (AbstractConfOption) o;
      return Objects.equal(getType(), that.getType()) &&
          Objects.equal(key, that.key);
    }
  
    @Override
    public int hashCode() {
      return Objects.hashCode(key);
    }
  
    @Override public String toString() {
      StringBuilder sb = new StringBuilder(30);
     sb.append("  ").append(key).append(" => ").append(getDefaultValueStr());
     sb.append(" (").append(getType().toString().toLowerCase()).append(")\n");
     return sb.toString();
   }
 
   /**
    * Check if the value set is the same as the default value
    *
    * @param conf Configuration
    * @return true if value set is default value
    */
   public abstract boolean isDefaultValue(Configuration conf);
 
   /**
    * Get string representation of default value
    *
    * @return String
    */
   public abstract String getDefaultValueStr();
 
   /**
    * Get type this option holds
    *
    * @return ConfOptionType
    */
   public abstract ConfOptionType getType();
 }