co.cask.cdap.proto.codec.MapReduceSpecificationCodec.java Source code

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Here is the source code for co.cask.cdap.proto.codec.MapReduceSpecificationCodec.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.proto.codec;

import co.cask.cdap.api.Resources;
import co.cask.cdap.api.mapreduce.MapReduceSpecification;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;

import java.lang.reflect.Type;
import java.util.Map;
import java.util.Set;

/**
 *
 */
public final class MapReduceSpecificationCodec extends AbstractSpecificationCodec<MapReduceSpecification> {

    @Override
    public JsonElement serialize(MapReduceSpecification src, Type typeOfSrc, JsonSerializationContext context) {
        JsonObject jsonObj = new JsonObject();

        jsonObj.addProperty("className", src.getClassName());
        jsonObj.addProperty("name", src.getName());
        jsonObj.addProperty("description", src.getDescription());

        if (src.getDriverResources() != null) {
            jsonObj.add("driverResources", context.serialize(src.getDriverResources()));
        }
        if (src.getMapperResources() != null) {
            jsonObj.add("mapperResources", context.serialize(src.getMapperResources()));
        }
        if (src.getReducerResources() != null) {
            jsonObj.add("reducerResources", context.serialize(src.getReducerResources()));
        }
        if (src.getInputDataSet() != null) {
            jsonObj.addProperty("inputDataSet", src.getInputDataSet());
        }
        if (src.getOutputDataSet() != null) {
            jsonObj.addProperty("outputDataSet", src.getOutputDataSet());
        }
        jsonObj.add("datasets", serializeSet(src.getDataSets(), context, String.class));
        jsonObj.add("properties", serializeMap(src.getProperties(), context, String.class));

        return jsonObj;
    }

    @Override
    public MapReduceSpecification deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        JsonObject jsonObj = json.getAsJsonObject();

        String className = jsonObj.get("className").getAsString();
        String name = jsonObj.get("name").getAsString();
        String description = jsonObj.get("description").getAsString();
        Resources driverResources = deserializeResources(jsonObj, "driver", context);
        Resources mapperResources = deserializeResources(jsonObj, "mapper", context);
        Resources reducerResources = deserializeResources(jsonObj, "reducer", context);
        JsonElement inputDataSetElem = jsonObj.get("inputDataSet");
        String inputDataSet = inputDataSetElem == null ? null : inputDataSetElem.getAsString();
        JsonElement outputDataSetElem = jsonObj.get("outputDataSet");
        String outputDataSet = outputDataSetElem == null ? null : outputDataSetElem.getAsString();

        Set<String> dataSets = deserializeSet(jsonObj.get("datasets"), context, String.class);
        Map<String, String> properties = deserializeMap(jsonObj.get("properties"), context, String.class);
        return new MapReduceSpecification(className, name, description, inputDataSet, outputDataSet, dataSets,
                properties, driverResources, mapperResources, reducerResources);
    }

    /**
     * Deserialize the resources field from the serialized object.
     *
     * @param jsonObj The object representing the MapReduceSpecification
     * @param prefix Field name prefix. Either "mapper" or "reducer"
     * @param context The context to deserialize object.
     * @return A {@link Resources} or {@code null}.
     */
    private Resources deserializeResources(JsonObject jsonObj, String prefix, JsonDeserializationContext context) {
        // See if it of new format
        String name = prefix + "Resources";
        JsonElement element = jsonObj.get(name);
        if (element != null) {
            return context.deserialize(element, Resources.class);
        }

        // Try the old format, which is an int field representing the memory in MB.
        name = prefix + "MemoryMB";
        element = jsonObj.get(name);
        if (element != null) {
            return new Resources(element.getAsInt());
        }
        return null;
    }
}