search_engine.java

java 写的一个新闻发布系统

//
//                                   ____.
//                       __/\ ______|    |__/\.     _______
//            __   .____|    |       \   |    +----+       \
//    _______|  /--|    |    |    -   \  _    |    :    -   \_________
//   \\______: :---|    :    :           |    :    |         \________>
//           |__\---\_____________:______:    :____|____:_____\
//                                      /_____|
//
//                 . . . i n   j a h i a   w e   t r u s t . . .
//
//
//  Search_Engine
//  DJ  20.02.2001
//
//  getInstance()
//  authoriseRender()
//  renderLink()
//  needsJahiaData()
//  handleActions()
//

package org.jahia.engines.search;

import java.util.*;                                 // HashMap
import javax.servlet.http.*;                        // HttpSession

import org.jahia.exceptions.*;                  // JahiaException
import org.jahia.utils.*;                       // JahiaConsole
import org.jahia.data.*;                        // JahiaData, ConnectionTypes
import org.jahia.params.*;                      // ParamBean
import org.jahia.registries.*;                  // ServicesRegistry
import org.jahia.engines.*;                     // JahiaEngine interface
import org.jahia.data.events.*;                 // JahiaEvent
import org.jahia.services.usermanager.*;        // JahiaUserManager
import org.jahia.services.search.*;
import org.jahia.data.search.*;


/**
 * This engine is called when the user wants to do a search on the jahia site. It displays
 * sorted results using a JSP output which leaves every aspect of the search results design
 * on the JSP coder.
 *
 * This engine doesn't implement any search algorithm, it calls the JahiaSearchService for
 * that.  Instead, this engine is here for interaction between the user and the service.
 *
 * The JSP template uses searchResult attribute to get the search results, and searchString
 * to see what the user searched for.
 *
 * @see org.jahia.services.search.JahiaSearchService
 * @author David Jilli
 */
public class Search_Engine implements JahiaEngine {

    private static  final   String              TEMPLATE_JSP = "/jsp/jahia/engines/search/searchresult.jsp";
    private	static	final	String				SEARCH_JSP_NAME = "searchresult.jsp";
    private static          Search_Engine        theObject   = null;
    private                 String              engineName  = "search";
    private                 EngineToolBox       toolBox;


    /***
        * constructor
        *
        */
    private Search_Engine()
    {
        // JahiaConsole.println( "Engine", "***** Starting Search Engine *****" );
        toolBox = EngineToolBox.getInstance();
    } // end constructor



    /***
        * returns a single instance of the object
        *
        */
    public static synchronized Search_Engine getInstance()
    {
        if (theObject == null) {
            theObject = new Search_Engine();
        }
        return theObject;
    } // end getInstance



    /***
        * authorises engine render
        *
        */
    public boolean authoriseRender( ParamBean jParams )
    {
        return true;					// always allowed to render search
    } // end authoriseRender



    /***
        * renders link to pop-up window
        *
        */
    public String renderLink( ParamBean jParams, Object theObj )
    throws JahiaException
    {
        String theUrl = jParams.composeEngineUrl( engineName, "" );
        if (theObj != null)
            theUrl = theUrl + theObj;
/*        if (theObj != null)  {
            int pos1 = theUrl.indexOf( "&pid=" );
            int pos2 = theUrl.indexOf( "&", pos1 + 1 );
            pos2 = (pos2 > -1) ? pos2 : theUrl.length();
            theUrl = theUrl.substring(0,pos1) + theUrl.substring(pos2,theUrl.length()) + theObj.toString();
        }*/
        return jParams.getResponse().encodeURL(theUrl);
    } // end renderLink



    /***
        * specifies if the engine needs the JahiaData object
        *
        */
    public boolean needsJahiaData( ParamBean jParams )
    {
        return true;
    } // end needsJahiaData



    /***
        * handles the engine actions
        *
        * @param        jParams             a ParamBean object
        * @param        jData               a JahiaData object (not mandatory)
        *
        */
    public void handleActions( ParamBean jParams, JahiaData jData )
    throws JahiaException
    {
        // initalizes the hashmap
//        HashMap engineMap = new HashMap();
        HashMap engineMap = (HashMap)jParams.getRequest().getAttribute( "engineMap" );
        if (engineMap == null)
            engineMap = new HashMap();

        processScreen( jParams, jData, engineMap );

        // displays the screen
        toolBox.displayScreen( jParams, engineMap );

    } // end handleActions



    /***
        * prepares the screen requested by the user
        *
        * @param        jParams             a ParamBean object
        *
        */
    public void processScreen( ParamBean jParams, JahiaData jData, HashMap engineMap )
    throws JahiaException
    {
        // check if a searchresult template exists in the template
        // directory, else uses the standard template found in the
        // jsp/engines directory
        String theTemplate = new String(TEMPLATE_JSP);
        String fileName = null;

        if ((jParams!=null) && (jParams.getPage()!=null) && (jParams.getPage().getPageTemplate()!=null))
        {
            fileName = jParams.getPage().getPageTemplate().getSourcePath();
            if (fileName.lastIndexOf ("/") != -1)
            {
                fileName = fileName.substring (0, fileName.lastIndexOf("/")+1) + SEARCH_JSP_NAME;
                JahiaConsole.println ("Search_Engine", "Trying to redirect search result to : "+fileName);
                theTemplate = fileName;
            }
        }

        String theScreen = jParams.getRequest().getParameter( "screen" );
        if (theScreen == null) {
            theScreen = "execute";
        }

        if (jParams.getRequest().getParameter( "from" ) != null) {
            engineMap.put ("searchResultFrom", Integer.valueOf(jParams.getRequest().getParameter("from")));
        }
        if (engineMap.get ( "searchResultFrom" ) == null) {
            engineMap.put ("searchResultFrom", new Integer(1));
        }

        String searchString = (String)engineMap.get ("searchString");
        if (searchString == null) {
            searchString = jParams.getRequest().getParameter ("search");
        }

        if(searchString == null) {
            searchString = "";
        } else {
            searchString = searchString.trim();
        }

        Integer  searchFrom = ((Integer)engineMap.get ("searchResultFrom"));
        if (searchFrom == null) {
            if (jParams.getRequest().getParameter("from")!=null)
            {
                searchFrom = Integer.valueOf(jParams.getRequest().getParameter("from"));
            }
        }
        if (searchFrom == null) {
            searchFrom = new Integer(1);
        }

        Integer  searchShow = ((Integer)engineMap.get ("searchShow"));
        if (searchShow == null) {
            if (jParams.getRequest().getParameter("show")!=null)
            {
                searchShow = Integer.valueOf(jParams.getRequest().getParameter("show"));
            }
        }

        //JahiaConsole.println ("Search_Engine","searchString : > " + (String)engineMap.get ("searchString"));



        // previous screen
        if (theScreen.equals("prev"))
        {
            if (engineMap.get("searchResultFrom")!=null)
                engineMap.put ("searchResultFrom",
                    new Integer(((searchFrom.intValue()-searchShow.intValue()<1)?1:(searchFrom.intValue()-searchShow.intValue())) ));
            searchFrom= new Integer(searchFrom.intValue()-searchShow.intValue());
        }

        // next screen
        if (theScreen.equals("next"))
        {
            if (engineMap.get("searchResultFrom")!=null)
                engineMap.put ("searchResultFrom",
                     new Integer(searchFrom.intValue()+searchShow.intValue()));
            searchFrom= new Integer(searchFrom.intValue()+searchShow.intValue());
        }

        String showStr="";
        if (searchShow!=null)
            showStr = "&show="+searchShow;
        engineMap.put( "searchPrevUrl", renderLink(jParams,showStr+"&screen=prev&search="+searchString+"&from="+searchFrom.intValue()) );
        engineMap.put( "searchNextUrl", renderLink(jParams,showStr+"&screen=next&search="+searchString+"&from="+searchFrom.intValue()) );


        // execute the search (called the 1st time)
        if (true)
        {
            engineMap.put( "engineOutputFile", theTemplate );

            engineMap.put( "jParams", jParams );
            engineMap.put( "jData", jData );
            engineMap.put( "renderType", new Integer(JahiaEngine.RENDERTYPE_FORWARD) );
            engineMap.put( "engineName", engineName );
            engineMap.put( "engineUrl", jParams.composeEngineUrl( engineName, "" ) );
            engineMap.put( "jahiaBuild", new Integer(jParams.settings().getBuildNumber()));
            engineMap.put( "javascriptUrl", jParams.settings().getJsHttpPath() );

            jParams.getRequest().setAttribute( "engineMap", engineMap );

            //JahiaConsole.println("SearchEngine","Searchstring: "+searchString);
            JahiaSearchResult searchResults = ServicesRegistry.getInstance().getJahiaSearchService().doSearch(searchString, jParams);

            if(searchResults == null) {
                searchResults = new JahiaSearchResult();
            }

            engineMap.put ("searchShow", searchShow);
            engineMap.put ("searchResults", searchResults);
            engineMap.put ("searchString", searchString);
        }
    } // end processScreen
}