/*
    *
    * 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.hbase.rest;
  
  import java.io.IOException;
  
  import javax.ws.rs.GET;
  import javax.ws.rs.Produces;
  import javax.ws.rs.core.CacheControl;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.UriInfo;
  import javax.ws.rs.core.Response.ResponseBuilder;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.rest.model.StorageClusterVersionModel;
  
  @InterfaceAudience.Private
  public class StorageClusterVersionResource extends ResourceBase {
    private static final Log LOG =
      LogFactory.getLog(StorageClusterVersionResource.class);
  
    static CacheControl cacheControl;
    static {
      cacheControl = new CacheControl();
      cacheControl.setNoCache(true);
      cacheControl.setNoTransform(false);
    }
  
    /**
     * Constructor
     * @throws IOException
     */
    public StorageClusterVersionResource() throws IOException {
      super();
    }
  
    @GET
    @Produces({MIMETYPE_TEXT, MIMETYPE_XML, MIMETYPE_JSON})
    public Response get(final @Context UriInfo uriInfo) {
      if (LOG.isTraceEnabled()) {
        LOG.trace("GET " + uriInfo.getAbsolutePath());
      }
      servlet.getMetrics().incrementRequests(1);
      try {
        StorageClusterVersionModel model = new StorageClusterVersionModel();
        model.setVersion(servlet.getAdmin().getClusterStatus().getHBaseVersion());
        ResponseBuilder response = Response.ok(model);
        response.cacheControl(cacheControl);
        servlet.getMetrics().incrementSucessfulGetRequests(1);
        return response.build();
      } catch (IOException e) {
        servlet.getMetrics().incrementFailedGetRequests(1);
        return Response.status(Response.Status.SERVICE_UNAVAILABLE)
          .type(MIMETYPE_TEXT).entity("Unavailable" + CRLF)
          .build();
      }
    }
  }