The R Project SVN R

/*============================================================================

  Project: Simple JAVA Search Engine for Keyword Search

  JAVA Source file for the class SearchEngine

  COPYRIGHT (C), 1998-2000, Thomas Baier, R Core Development Team

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  $Revision: 1.5 $

  $Date: 2000/02/10 17:03:55 $

  $Author: leisch $

============================================================================*/

import java.applet.*;

import java.awt.*;

import java.net.*;

import java.io.*;

import java.util.*;

public class SearchEngine extends Applet

{

  public SearchEngine ()

  {

    iIndexTable = null;

    iSearchTerm = null;

    Tracer.write ("SearchEngine initializing\n");

    return;

  }

  public String getAppletInfo ()

  {

    return "Name: SearchEngine\r\n" +

      "Author: Thomas Baier\r\n" +

      "(C) 1998-2000 Thomas Baier, R Core Development Team";

  }

  public void init ()

  {

    resize(640, 240);

    // get the name of the index file

    String indexName = getParameter (cIndexKeyword);

    String searchTerm = getParameter (cSearchKeyword);

    Tracer.write ("Index file is \"" + indexName + "\"\n");

    Tracer.write ("Search term is \"" + searchTerm + "\"\n");

    // use a default index file if none specified

    if (indexName == null) {

      indexName = cIndexFile;

    }

    iSearchTerm = searchTerm;

    /*

     * examine the URL to get the search term...

     *

     * if the URL ends with ?SEARCHTERM=xxxxx we know, xxxxx is the search term

     */

    {

      URL url = getDocumentBase ();

      String urlString = url.toString ();

      int index = urlString.indexOf ("?" + cSearchKeyword + "=");

      Tracer.write ("URL is \"" + urlString + "\"\n");

      // if found, take the rest as the search string

      if (index >= 0) {

	iSearchTerm =

	  urlString.substring (index + 2 + cSearchKeyword.length ());

	Tracer.write ("found search term \"" + iSearchTerm + "\" in URL\n");

      }

    }

    readIndexFile (indexName);

    return;

  }

  public void destroy ()

  {

    return;

  }

  public void paint (Graphics g)

  {

    return;

  }

  public void start ()

  {

    Tracer.start ();

    return;

  }

  public void stop ()

  {

    Tracer.stop ();

    return;

  }

  /* perform the search and return result as string */

  public String search (String key, boolean searchDesc,

			boolean searchKeywords, boolean searchAliases)

  {

    iSearchTerm = key;

    Tracer.write ("Search for \"" + iSearchTerm + "\" started\n");

    if(searchDesc){

      Tracer.write("Searching in Descriptions\n");

    }

    if(searchKeywords){

      Tracer.write("Searching in Keywords\n");

    }

    if(searchAliases){

      Tracer.write("Searching in Aliases\n");

    }

    Vector foundItems = null;

    if (iSearchTerm != null) {

      foundItems = iIndexTable.search (iSearchTerm, searchDesc,

				       searchKeywords, searchAliases);

    }

    else {

      foundItems = null;

    }

    String result = null;

    // if nothing found, return a special string

    if (foundItems == null) {

      result = "No matches for <b>\"" + 

	iSearchTerm +

	"\"</b> have been found!<hr>";

    }

    else {

      Enumeration cursor = foundItems.elements ();

      result =

	"The search string was <b>\"" +

	iSearchTerm +

	"</b>\"" +

	"<hr>" +

	"<dl>";

      while (cursor.hasMoreElements ()) {

	IndexEntry entry = (IndexEntry) cursor.nextElement ();

	result +=

	  "<dt><a href=\"" +

	  entry.getURL () +

	  "\">" +

	  entry.getEntry () +

	  "</a></dt>\n";

	result += "<dd>" + entry.getDescription () + "</dd>\n";

      }

      result += "</dl>";

    }

    return result;

  }

  private void readIndexFile (String idxFile)

  {

    // create the index table

    iIndexTable = new IndexTable ();

    URL baseURL = getCodeBase ();

    // get the index file and parse its contents

    try {

      URL idxFileURL = new URL (baseURL,idxFile);

      // get an IndexStream object for ease of parsing

      IndexStream idxStream = new IndexStream (idxFileURL);

      // now start parsing...

      /*

       * An entry consists of a title, keywords, aliases, an URL and

       * a description, everything else is ignored.

       * Every entry starts with the keyword

       * "Entry" (case is ignored)

       *

       * must-have entries are "Entry" and "Keywords"

       *

       * 98-06-01: bugfix: don't null the variables

       */

      String entry = "";

      String keywords = "";

      String aliases = "";

      String url = "";

      String description = "";

      String prefix = "";

      String suffix = "";

      Value value = idxStream.popEntry ();

      while (value != null) {

	// parse the value now

	if (value.getKey ().equalsIgnoreCase ("entry")) {

	  // if a new entry is about to start, add the current one

	  addEntry (entry,keywords,aliases,description,url,prefix,suffix);

	  entry = value.getValue ();

	  aliases = entry;

	  keywords = "";

	  url = "";

	  description = "";

	} else if (value.getKey ().equalsIgnoreCase ("keywords")) {

	  keywords += value.getValue ();

	} else if (value.getKey ().equalsIgnoreCase ("aliases")) {

	  aliases += value.getValue ();

	} else if (value.getKey ().equalsIgnoreCase ("url")) {

	  url = prefix + value.getValue () + suffix;

	} else if (value.getKey ().equalsIgnoreCase ("description")) {

	  description = value.getValue ();

	} else if (value.getKey ().equalsIgnoreCase ("prefix")) {

	  prefix = value.getValue ();

	  Tracer.write ("using new URL prefix \"" + prefix + "\"\n");

	} else if (value.getKey ().equalsIgnoreCase ("suffix")) {

	  suffix = value.getValue ();

	  Tracer.write ("using new URL suffix \"" + suffix + "\"\n");

	}

	value = idxStream.popEntry ();

      }

      // the final entry just read

      addEntry (entry,keywords,aliases,description,url,prefix,suffix);

    } catch (MalformedURLException exc) {

      // an error occured while reading...

    }

    return;

  }

  private void addEntry (String entry,String keywords,

			 String aliases,

			 String description,String url,

			 String prefix,String suffix)

  {

    // the entry must be set

    if (entry.length () == 0) {

      return;

    }

    // if the URL is empty, construct one following the rule:

    // URL = prefix + entry + suffix

    if (url.length () == 0) {

      url = prefix + entry + suffix;

    }

    IndexEntry idxEntry =

      new IndexEntry (entry,keywords,aliases,description,url);

    iIndexTable.addElement (idxEntry);

    return;

  }

  /* Instance Variables */

  private IndexTable iIndexTable;

  private String     iSearchTerm;

  /* Static Data */

  private static final String cIndexFile = "index.txt";

  private static final String cIndexKeyword = "INDEXFILE";

  private static final String cSearchKeyword = "SEARCHTERM";

}

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// mode: Java

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