/*

  * 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();

 }