TopologyCollectionMarshaller.java

/**
 * 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.gateway.service.admin;

import org.eclipse.persistence.jaxb.JAXBContextProperties;

import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.*;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;

@Provider
@Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
public class TopologyCollectionMarshaller implements MessageBodyWriter<TopologiesResource.SimpleTopologyWrapper> {

  @Context
  protected Providers providers;

  @Override
  public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
    return (TopologiesResource.SimpleTopologyWrapper.class == type);
  }

  @Override
  public long getSize(TopologiesResource.SimpleTopologyWrapper instance, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
    return -1;
  }

  @Override
  public void writeTo(TopologiesResource.SimpleTopologyWrapper instance, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
    try {
      Map<String, Object> properties = new HashMap<String, Object>(1);
      properties.put( JAXBContextProperties.MEDIA_TYPE, mediaType.toString());
      JAXBContext context = JAXBContext.newInstance(new Class[]{TopologiesResource.SimpleTopologyWrapper.class}, properties);
      Marshaller m = context.createMarshaller();
      m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
      m.marshal(instance, entityStream);

    } catch (JAXBException e) {
      throw new IOException(e);
    }
  }
}