RepositoryListController.java :  » RSS-RDF » sesame » org » openrdf » http » server » repository » Java Open Source

/*
 * Copyright Aduna (http://www.aduna-software.com/) (c) 2007.
 *
 * Licensed under the Aduna BSD-style license.
 */
package org.openrdf.http.server.repository;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContextException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;

import org.openrdf.http.server.ProtocolUtil;
import org.openrdf.http.server.ServerHTTPException;
import org.openrdf.model.ValueFactory;
import org.openrdf.query.BindingSet;
import org.openrdf.query.QueryLanguage;
import org.openrdf.query.TupleQueryResult;
import org.openrdf.query.algebra.evaluation.QueryBindingSet;
import org.openrdf.query.impl.TupleQueryResultImpl;
import org.openrdf.query.resultio.TupleQueryResultWriterFactory;
import org.openrdf.query.resultio.TupleQueryResultWriterRegistry;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import org.openrdf.repository.RepositoryException;
import org.openrdf.repository.manager.LocalRepositoryManager;

/**
 * Handles requests for the list of repositories available on this server.
 * 
 * @author Herko ter Horst
 */
public class RepositoryListController extends AbstractController {

  private static final String REPOSITORY_LIST_QUERY;

  static {
    StringBuilder query = new StringBuilder(256);
    query.append("SELECT id, title, \"true\"^^xsd:boolean as \"readable\", \"true\"^^xsd:boolean as \"writable\"");
    query.append("FROM {} rdf:type {sys:Repository};");
    query.append("        [rdfs:label {title}];");
    query.append("        sys:repositoryID {id} ");
    query.append("USING NAMESPACE sys = <http://www.openrdf.org/config/repository#>");
    REPOSITORY_LIST_QUERY = query.toString();
  }

  private LocalRepositoryManager repositoryManager;

  public RepositoryListController()
    throws ApplicationContextException
  {
    setSupportedMethods(new String[] { METHOD_GET });
  }

  public void setRepositoryManager(LocalRepositoryManager repMan) {
    repositoryManager = repMan;
  }

  @Override
  protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
    throws Exception
  {
    Repository systemRepository = repositoryManager.getSystemRepository();
    ValueFactory vf = systemRepository.getValueFactory();

    try {
      RepositoryConnection con = systemRepository.getConnection();
      try {
        // FIXME: The query result is cached here as we need to close the
        // connection before returning. Would be much better to stream the
        // query result directly to the client.

        List<String> bindingNames = new ArrayList<String>();
        List<BindingSet> bindingSets = new ArrayList<BindingSet>();

        TupleQueryResult queryResult = con.prepareTupleQuery(QueryLanguage.SERQL, REPOSITORY_LIST_QUERY).evaluate();
        try {
          // Determine the repository's URI
          StringBuffer requestURL = request.getRequestURL();
          if (requestURL.charAt(requestURL.length() - 1) != '/') {
            requestURL.append('/');
          }
          String namespace = requestURL.toString();

          while (queryResult.hasNext()) {
            QueryBindingSet bindings = new QueryBindingSet(queryResult.next());

            String id = bindings.getValue("id").stringValue();
            bindings.addBinding("uri", vf.createURI(namespace, id));

            bindingSets.add(bindings);
          }

          bindingNames.add("uri");
          bindingNames.addAll(queryResult.getBindingNames());
        }
        finally {
          queryResult.close();
        }

        TupleQueryResultWriterFactory factory = ProtocolUtil.getAcceptableService(request, response,
            TupleQueryResultWriterRegistry.getInstance());

        Map<String, Object> model = new HashMap<String, Object>();
        model.put(QueryResultView.QUERY_RESULT_KEY, new TupleQueryResultImpl(bindingNames, bindingSets));
        model.put(QueryResultView.FILENAME_HINT_KEY, "repositories");
        model.put(QueryResultView.FACTORY_KEY, factory);

        return new ModelAndView(TupleQueryResultView.getInstance(), model);
      }
      finally {
        con.close();
      }
    }
    catch (RepositoryException e) {
      throw new ServerHTTPException(e.getMessage(), e);
    }
  }
}