/*

  * 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 org.codehaus.jackson.map.ObjectMapper;

 import org.codehaus.jackson.type.TypeReference;

 import java.io.IOException;

 /**

  * JSON String configuration option

  */

 public class JsonStringConfOption extends AbstractConfOption {

   /** Logger */

   private static final Logger LOG =

       Logger.getLogger(JsonStringConfOption.class);

   /**

    * Constructor

    *

    * @param key String key name

    * @param description String description of option

    */

   public JsonStringConfOption(String key, String description) {

     super(key, description);

   }

   /**

    * Set JSON value

    *

    * @param conf Configuration

    * @param value Json value

    */

   public void set(Configuration conf, Object value) {

     ObjectMapper mapper = new ObjectMapper();

     String jsonStr;

     try {

       jsonStr = mapper.writeValueAsString(value);

       conf.set(getKey(), jsonStr);

     } catch (IOException e) {

       throw new IllegalStateException("Failed to set " + getKey() +

           " with json value from " + value);

     }

   }

   /**

    * Get raw JSON string

    *

    * @param conf Configuration

    * @return raw JSON string value

    */

   public String getRaw(Configuration conf) {

     return conf.get(getKey());

   }

   /**

    * Get JSON value

    *

    * @param <T> JSON type

    * @param conf Configuration

    * @param klass Class to read into

    * @return JSON value

    */

   public <T> T get(Configuration conf, Class<T> klass) {

     String jsonStr = getRaw(conf);

     T value = null;

     if (jsonStr != null) {

       ObjectMapper mapper = new ObjectMapper();

       try {

         value = mapper.readValue(jsonStr, klass);

       } catch (IOException e) {

         throw new IllegalStateException("Failed to read json from key " +

             getKey() + " with class " + klass);

       }

     }

     return value;

   }

   /**

    * Get JSON value

    *

    * @param <T> JSON type

    * @param conf Configuration

    * @param typeReference TypeReference for JSON type

    * @return JSON value

    */

   public <T> T get(Configuration conf, TypeReference<T> typeReference) {

     String jsonStr = getRaw(conf);

     T value = null;

     if (jsonStr != null) {

       ObjectMapper mapper = new ObjectMapper();

       try {

         value = mapper.<T>readValue(jsonStr, typeReference);

       } catch (IOException e) {

         throw new IllegalStateException("Failed to read json from key " +

             getKey() + " with class " + typeReference);

       }

     }

     return value;

   }

   /**

    * Get JSON value, or default if not present

    *

    * @param <T> JSON type

    * @param klass Class to read into

    * @param conf Configuration

    * @param defaultValue Default value if not found

    * @return JSON value

    */

   public <T> T getWithDefault(Configuration conf, Class<T> klass,

       T defaultValue) {

     if (contains(conf)) {

       return get(conf, klass);

     } else {

       return defaultValue;

     }

   }

   @Override

   public String getDefaultValueStr() {

     return "null";

   }

   @Override

   public boolean isDefaultValue(Configuration conf) {

     return !contains(conf);

   }

   @Override

   public ConfOptionType getType() {

     return ConfOptionType.STRING;

   }

 }