/**
* 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.tools.rumen.state;
import java.io.IOException;
import org.apache.hadoop.tools.rumen.state.StatePool.StatePair;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.DeserializationContext;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.deser.std.StdDeserializer;
import org.codehaus.jackson.node.ObjectNode;
/**
* Rumen JSON deserializer for deserializing the {@link State} object.
*/
public class StateDeserializer extends StdDeserializer<StatePair> {
public StateDeserializer() {
super(StatePair.class);
}
@Override
public StatePair deserialize(JsonParser parser,
DeserializationContext context)
throws IOException, JsonProcessingException {
ObjectMapper mapper = (ObjectMapper) parser.getCodec();
// set the state-pair object tree
ObjectNode statePairObject = (ObjectNode) mapper.readTree(parser);
Class<?> stateClass = null;
try {
stateClass =
Class.forName(statePairObject.get("className").getTextValue().trim());
} catch (ClassNotFoundException cnfe) {
throw new RuntimeException("Invalid classname!", cnfe);
}
String stateJsonString = statePairObject.get("state").toString();
State state = (State) mapper.readValue(stateJsonString, stateClass);
return new StatePair(state);
}
}