| /** |
| * 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; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| import com.fasterxml.jackson.core.JsonEncoding; |
| import com.fasterxml.jackson.core.JsonGenerator; |
| import com.fasterxml.jackson.core.Version; |
| import com.fasterxml.jackson.databind.ObjectMapper; |
| import com.fasterxml.jackson.databind.module.SimpleModule; |
| import org.apache.hadoop.mapreduce.ID; |
| import org.apache.hadoop.tools.rumen.datatypes.DataType; |
| import org.apache.hadoop.tools.rumen.serializers.DefaultRumenSerializer; |
| import org.apache.hadoop.tools.rumen.serializers.ObjectStringSerializer; |
| |
| /** |
| * Simple wrapper around {@link JsonGenerator} to write objects in JSON format. |
| * @param <T> The type of the objects to be written. |
| */ |
| public class JsonObjectMapperWriter<T> implements Closeable { |
| private JsonGenerator writer; |
| |
| public JsonObjectMapperWriter(OutputStream output, boolean prettyPrint) throws IOException { |
| ObjectMapper mapper = new ObjectMapper(); |
| |
| // define a module |
| SimpleModule module = new SimpleModule( |
| "Default Serializer", new Version(0, 1, 1, "FINAL", "", "")); |
| // add various serializers to the module |
| // add default (all-pass) serializer for all rumen specific data types |
| module.addSerializer(DataType.class, new DefaultRumenSerializer()); |
| // add a serializer to use object.toString() while serializing |
| module.addSerializer(ID.class, new ObjectStringSerializer<ID>()); |
| |
| // register the module with the object-mapper |
| mapper.registerModule(module); |
| |
| writer = mapper.getFactory().createGenerator(output, JsonEncoding.UTF8); |
| if (prettyPrint) { |
| writer.useDefaultPrettyPrinter(); |
| } |
| } |
| |
| public void write(T object) throws IOException { |
| writer.writeObject(object); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| writer.close(); |
| } |
| } |