Metacat

import java.io.PrintWriter;

import java.io.IOException;

import java.util.Enumeration;

import java.util.Hashtable;

import javax.servlet.ServletConfig;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.ServletInputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpUtils;

/**

 * A metadata catalog server implemented as a Java Servlet

 */

public class MetaCatServlet extends HttpServlet {

  private ServletConfig		config = null;

  private ServletContext	context = null;

  DBSimpleQuery		queryobj = null;

  DBReader		docreader = null;

  static  String 	user = "jones";

  static  String 	password = "your-pw-goes-here";

  static  String 	defaultDB = "jdbc:oracle:thin:@localhost:1521:test";

  public void init( ServletConfig config ) throws ServletException {

    try {

      super.init( config );

      this.config = config;

      this.context = config.getServletContext();

      try {

        queryobj = new DBSimpleQuery(user, password, defaultDB);

        docreader = new DBReader(user, password, defaultDB);

      } catch (Exception e) {

      }

    } catch ( ServletException ex ) {

      throw ex;

    }

  }

  public void doGet (HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

    // Get the parameters from the form

    String querystring = request.getQueryString();

    Hashtable params = HttpUtils.parseQueryString(querystring);

    // Process the data and send back the response

    handleGetOrPost(response, params);

  }

  public void doPost( HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

    // Get the input data from the client

    ServletInputStream in = request.getInputStream();

    int len = request.getContentLength();

    // Parse the input data into a Hashtable

    Hashtable params = HttpUtils.parsePostData(len, in);

    // Process the data and send back the response

    handleGetOrPost(response, params);

  }

  /**

   * routine to control servlet response depending on the action requested

   * Valid "action" parameters are:

   *     query -- query the text values of all elements and attributes

   *              and return a result set of nodes

   *  getdocument -- display an XML document in XML or HTML given a document ID

   */

  private void handleGetOrPost(HttpServletResponse response, Hashtable params) 

    throws ServletException, IOException {

    // Get a handle to the output stream back to the client

    PrintWriter out = response.getWriter();

    String action = ((String[])params.get("action"))[0];

    if (action.equals("query")) {

      handleQueryAction(out, params, response);

    } else if (action.equals("getdocument")) {

      handleGetDocumentAction(out, params, response);

    }

    // Close the stream to the client

    out.close();

  }

  private void handleQueryAction(PrintWriter out, Hashtable params, 

               HttpServletResponse response) {

      // Run the query

      String query = ((String[])params.get("query"))[0]; 

      Hashtable nodelist = queryobj.findRootNodes(query);

      // set content type and other response header fields first

      response.setContentType("text/xml");

      // Print the resulting root nodes

      long nodeid;

      out.println("<?xml version=\"1.0\"?>\n");

      out.println("<resultset>\n");

      out.println("  <query>" + query + "</query>");

      Enumeration rootlist = nodelist.keys(); 

      while (rootlist.hasMoreElements()) {

        nodeid = ((Long)rootlist.nextElement()).longValue();

        out.println("  <nodeid>" + nodeid + "</nodeid>");

      }

      out.println("</resultset>");

  }

  private void handleGetDocumentAction(PrintWriter out, Hashtable params, 

               HttpServletResponse response) {

      // Get the document indicated

      String docid = ((String[])params.get("docid"))[0]; 

      String doc = docreader.readXMLDocument((new Long(docid)).longValue());

      // set content type and other response header fields first

      response.setContentType("text/xml");

      out.println(doc);

      // Print the resulting root nodes

      //out.println("<?xml version=\"1.0\"?>\n");

      //out.println("<docid>" + docid + "</docid>");

  }

}