pagexrefmanager.java

java 写的一个新闻发布系统

package org.jahia.content;

import java.util.*;

import org.jahia.utils.JahiaConsole;

/**
 * Title:        Jahia
 * Description:  The purpose of this class is to provide a cross reference
 * system between pages and pages, in order to know which pages reference
 * a specific page . This is necessary since currently this information is defined
 * only by template developpers and is useful for the HTML cache system when a
 * container modification is done. This class allows lookups such as : "which
 * pages access this page ?"
 * Copyright:    Copyright (c) 2002
 * Company:      Jahia Ltd
 * @author Serge Huber
 * @version 1.0
 */

public class PageXRefManager {

    private static final String NAME_SEPARATOR = "_";

    private static PageXRefManager theObject = null;

    protected PageXRefManager() {
        JahiaConsole.println("PageXRefManager",
                             "Initializing...");
    }

    /**
     * Returns a singleton instance of this service
     * Note : this is a synchronized access method so it might affect performance
     * if a lot of threads must access it simultaneously.
     * @returns the singleton instance.
     */
    public static synchronized PageXRefManager getInstance()
    {
        if (theObject == null) {
            theObject = new PageXRefManager();
        }
        return theObject;
    } // end getInstance

    /**
     * Retrieves a list of pageIDs that contain references to a specific
     * page
     * @param siteName name of the site for which to use this xref cache
     * @param targetPageID the target pageID for which to send xrefs.
     * @returns a Set of Integers containing pageIDs that reference the target
     * page.
     */
    public Set getPageIDs(String siteName, int targetPageID) {

        /*
        JahiaConsole.println("PageXRefManager.getPageIDs",
                             "Getting page ids for page " + Integer.toString(targetPageID));
        */
        PageKey pageKey = new PageKey(siteName, targetPageID);

        Set objectRefs = CrossReferenceManager.getInstance().getObjectXRefs(pageKey);
        Set pageIDs = new TreeSet();
        if (objectRefs == null) {
            JahiaConsole.println("PageXRefManager.getPageIDs",
                                 "No references found for page " + targetPageID);
            return pageIDs;
        }
        Iterator objectRefIter = objectRefs.iterator();
        while (objectRefIter.hasNext()) {
            Object ref = objectRefIter.next();
            if (ref instanceof ObjectKey) {
                ObjectKey refKey = (ObjectKey) ref;
                if (PageKey.PAGE_TYPE.equals(refKey.getType())) {
                    PageKey pageRefKey = (PageKey) refKey;
                    Integer pageID = new Integer(pageRefKey.getPageID());
                    pageIDs.add(pageID);
                } else {
                    JahiaConsole.println("PageXRefManager.getPageIDs",
                                         "Expected page type in cross reference list, ignoring value...  ");
                }
            } else {
                JahiaConsole.println("PageXRefManager.getPageIDs",
                                     "Invalid key object in cross reference list, ignoring... ");
            }
        }
        return pageIDs;
    }

    /**
     * Adds or updates a cross reference between an target and
     * a page reference
     * @param siteName the site name for which we are managing xrefs
     * @param targetPageID the target page ID for which to add a xref
     * @param refPageID the page that has the xref to the target page
     */
    public void setPageID(String siteName, int targetPageID, int refPageID) {
        /*
        JahiaConsole.println("PageXRefManager.setPageID",
                             "Target=" + Integer.toString(targetPageID) +
                             ", refPageID=" + Integer.toString(refPageID));
		*/                             
        //JahiaConsole.println("PageXRefManager","siteName =" + siteName);                     
        //JahiaConsole.println("PageXRefManager","targetPageID =" + targetPageID);                     
        //JahiaConsole.println("PageXRefManager","refPageID =" + refPageID);                     
        PageKey pageKey = new PageKey(siteName, targetPageID);
        PageKey refPageKey = new PageKey(siteName, refPageID);
        CrossReferenceManager.getInstance().setObjectXRef(pageKey, refPageKey);
    }

    /**
     * Removes all the cross references for a specified page
     * @param siteName the site name for which we are managing xrefs
     * @param targetPageID the target page ID for which to add a xref
     */
    public void removePage(String siteName, int targetPageID) {
        PageKey pageKey = new PageKey(siteName, targetPageID);
        CrossReferenceManager.getInstance().removeObjectXRefs(pageKey);
    }

}