001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.lib.wsrs;
020
021import org.apache.commons.io.Charsets;
022import org.apache.hadoop.classification.InterfaceAudience;
023import org.json.simple.JSONStreamAware;
024
025import javax.ws.rs.Produces;
026import javax.ws.rs.WebApplicationException;
027import javax.ws.rs.core.MediaType;
028import javax.ws.rs.core.MultivaluedMap;
029import javax.ws.rs.ext.MessageBodyWriter;
030import javax.ws.rs.ext.Provider;
031import java.io.IOException;
032import java.io.OutputStream;
033import java.io.OutputStreamWriter;
034import java.io.Writer;
035import java.lang.annotation.Annotation;
036import java.lang.reflect.Type;
037
038@Provider
039@Produces(MediaType.APPLICATION_JSON)
040@InterfaceAudience.Private
041public class JSONProvider implements MessageBodyWriter<JSONStreamAware> {
042  private static final String ENTER = System.getProperty("line.separator");
043
044  @Override
045  public boolean isWriteable(Class<?> aClass, Type type, Annotation[] annotations, MediaType mediaType) {
046    return JSONStreamAware.class.isAssignableFrom(aClass);
047  }
048
049  @Override
050  public long getSize(JSONStreamAware jsonStreamAware, Class<?> aClass, Type type, Annotation[] annotations,
051                      MediaType mediaType) {
052    return -1;
053  }
054
055  @Override
056  public void writeTo(JSONStreamAware jsonStreamAware, Class<?> aClass, Type type, Annotation[] annotations,
057                      MediaType mediaType, MultivaluedMap<String, Object> stringObjectMultivaluedMap,
058                      OutputStream outputStream) throws IOException, WebApplicationException {
059    Writer writer = new OutputStreamWriter(outputStream, Charsets.UTF_8);
060    jsonStreamAware.writeJSONString(writer);
061    writer.write(ENTER);
062    writer.flush();
063  }
064
065}