content: /**
   * 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.solr.handler;
  
  import java.io.File;
  
  import org.apache.solr.common.SolrException;
  import org.apache.solr.common.params.CommonParams;
  import org.apache.solr.common.params.SolrParams;
  import org.apache.solr.core.SolrCore;
  import org.apache.solr.request.SolrQueryRequest;
  import org.apache.solr.request.SolrRequestHandler;
  import org.apache.solr.response.SolrQueryResponse;
  
  
  /**
   * Ping solr core
   * 
   * @since solr 1.3
   */
  public class PingRequestHandler extends RequestHandlerBase 
  {
    @Override
    public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throws Exception 
    {
      SolrParams params = req.getParams();
      SolrParams required = params.required();
      SolrCore core = req.getCore();
      
      // Check if the service is available
      String healthcheck = core.getSolrConfig().get("admin/healthcheck/text()", null );
      if( healthcheck != null && !new File(healthcheck).exists() ) {
        throw new SolrException(SolrException.ErrorCode.SERVICE_UNAVAILABLE, "Service disabled", true);
      }
      
      // Get the RequestHandler
      String qt = required.get( CommonParams.QT );
      SolrRequestHandler handler = core.getRequestHandler( qt );
      if( handler == null ) {
        throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, 
            "Unknown RequestHandler: "+qt );
      }
      
      if( handler instanceof PingRequestHandler ) {
        throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, 
            "Cannot execute the PingRequestHandler recursively" );
      }
      
      // Execute the ping query and catch any possible exception
      Throwable ex = null;
      try {
        SolrQueryResponse pingrsp = new SolrQueryResponse();
        core.execute(handler, req, pingrsp );
        ex = pingrsp.getException();
      }
      catch( Throwable th ) {
        ex = th;
      }
      
      // Send an error or an 'OK' message (response code will be 200)
      if( ex != null ) {
        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, 
            "Ping query caused exception: "+ex.getMessage(), ex );
      }
      rsp.add( "status", "OK" );
    }
    
    
    //////////////////////// SolrInfoMBeans methods //////////////////////
  
    @Override
    public String getVersion() {
      return "$Revision: 1142180 $";
    }
  
    @Override
    public String getDescription() {
      return "Reports application health to a load-balancer";
    }
  
    @Override
    public String getSourceId() {
      return "$Id: PingRequestHandler.java 1142180 2011-07-02 09:04:29Z uschindler $";
    }
  
    @Override
    public String getSource() {
      return "$URL: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_3_5/solr/core/src/java/org/apache/solr/handler/PingRequestHandler.java $";
    }
  }
  