menurepository.java

Struts Menu这是为基于JSP和Struts的应用程序提供的Web菜单框架。菜单可以在一个XML文件中定义

/*
 * MenuRepository.java
 *
 * Created on January 29, 2001, 9:51 AM
 */
package net.sf.navigator.menu;

import java.io.InputStream;
import java.util.*;

import javax.servlet.ServletContext;

import net.sf.navigator.displayer.MenuDisplayerMapping;
import net.sf.navigator.util.LoadableResource;
import net.sf.navigator.util.LoadableResourceException;

import org.apache.commons.collections.FastHashMap;
import org.apache.commons.digester.Digester;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


/**
 *
 * @author  ssayles, mraible
 * @version
 */
public class MenuRepository implements LoadableResource {
    //~ Static fields/initializers =============================================

    public static final String MENU_REPOSITORY_KEY =
        "net.sf.navigator.menu.MENU_REPOSITORY";
    private static Log log = LogFactory.getLog(MenuRepository.class);

    //~ Instance fields ========================================================

    protected String config = null;
    protected String name = null;
    protected ServletContext servletContext = null;
    protected FastHashMap menus = new FastHashMap();
    protected FastHashMap displayers = new FastHashMap();
    protected FastHashMap templates = new FastHashMap();
    
    //~ Methods ================================================================
    public Set getMenuNames() {
        return menus.keySet();
    }

    /**
     * Convenience method for dynamic menus - returns the top-level menus
     * only.
     * @return
     */
    public List getTopMenus() {
        List topMenus = new ArrayList();
        if (menus == null) {
            log.warn("No menus found in repository!");
            return topMenus;
        }

        for (Iterator it = menus.keySet().iterator(); it.hasNext();) {
            String name = (String) it.next();
            MenuComponent menu = getMenu(name);
            if (menu.getParent() == null) {
                topMenus.add(menu);
            }
        }
        return topMenus;
    }

    public MenuComponent getMenu(String menuName) {
        return (MenuComponent) menus.get(menuName);
    }

    public MenuDisplayerMapping getMenuDisplayerMapping(String displayerName) {
        MenuDisplayerMapping mapping =
            (MenuDisplayerMapping) displayers.get(displayerName);

        return mapping;
    }

    protected Digester initDigester() {
        Digester digester = new Digester();
        digester.setClassLoader(Thread.currentThread().getContextClassLoader());
        digester.push(this);

        //digester.setDebug(getDebug());
        // 1
        digester.addObjectCreate("MenuConfig/Menus/Menu",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu");
        digester.addSetNext("MenuConfig/Menus/Menu", "addMenu");

        // 2
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item", "addMenuComponent",
            "net.sf.navigator.menu.MenuComponent");

        // 3        
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item/Item",
            "addMenuComponent", "net.sf.navigator.menu.MenuComponent");

        // 4
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item/Item/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item/Item/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item/Item/Item",
            "addMenuComponent", "net.sf.navigator.menu.MenuComponent");

        // 5
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item/Item/Item/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "addMenuComponent", "net.sf.navigator.menu.MenuComponent");

        // 6
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item/Item/Item/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "addMenuComponent", "net.sf.navigator.menu.MenuComponent");

        // 7
        digester.addObjectCreate("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "net.sf.navigator.menu.MenuComponent", "type");
        digester.addSetProperties("MenuConfig/Menus/Menu/Item/Item/Item/Item");
        digester.addSetNext("MenuConfig/Menus/Menu/Item/Item/Item/Item",
            "addMenuComponent", "net.sf.navigator.menu.MenuComponent");

        digester.addObjectCreate("MenuConfig/Displayers/Displayer",
            "net.sf.navigator.displayer.MenuDisplayerMapping", "mapping");
        digester.addSetProperties("MenuConfig/Displayers/Displayer");
        digester.addSetNext("MenuConfig/Displayers/Displayer",
            "addMenuDisplayerMapping",
            "net.sf.navigator.displayer.MenuDisplayerMapping");
        digester.addSetProperty("MenuConfig/Displayers/Displayer/SetProperty",
            "property", "value");
            
        return digester;
    }

    /**
     * Adds a new menu.  This is called when parsing the menu xml definition.
     *
     * @param menu The menu component to add.
     */
    public void addMenu(MenuComponent menu) {
        if (menus.containsKey(menu.getName())) {
            if (log.isDebugEnabled()) {
                log.warn("Menu '" + menu.getName()
                        + "' already exists in repository");
            }
            List children = getMenu(menu.getName()).getComponents();
            if (children != null && menu.getComponents() != null) {
                for (Iterator it = children.iterator();it.hasNext();) {
                    MenuComponent child = (MenuComponent) it.next();
                    menu.addMenuComponent(child);
                }
            }
        }
        menus.put(menu.getName(), menu);
    }

    public void addMenuDisplayerMapping(MenuDisplayerMapping displayerMapping) {
        displayers.put(displayerMapping.getName(), displayerMapping);
    }

    /**
     * This method is so menu repositories can retrieve displayers from the
     * default repository specified in menu-config.xml
     * @return the displayers specified in this repository
     */
    public FastHashMap getDisplayers() {
        return displayers;
    }

    /**
     * Allow the displayers to be set as a whole.  This should only be used
     * when copying the displayers from the default repository to a newly
     * created repository.
     * @param displayers
     */
    public void setDisplayers(FastHashMap displayers) {
        this.displayers = displayers;
    }

    public void load() throws LoadableResourceException {
        if (getServletContext() == null) {
            throw new LoadableResourceException("no reference to servlet context found");
        }

        InputStream input = null;
        Digester digester = initDigester();

        try {
            input = getServletContext().getResourceAsStream(config);
            digester.parse(input);

            menus.setFast(true);
        } catch (Exception e) {
            e.printStackTrace();
            throw new LoadableResourceException("Error parsing resource file: " +
                config + " nested exception is: " + e.getMessage());
        } finally {
            try {
                input.close();
            } catch (Exception e) {}
        }
    }

    public void reload() throws LoadableResourceException {
        menus.setFast(false);
        menus.clear();
        displayers.setFast(false);
        displayers.clear();
        load();
    }

    public void setLoadParam(String loadParam) {
        config = loadParam;
    }

    public String getLoadParam() {
        return config;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public ServletContext getServletContext() {
        return servletContext;
    }

    public void setServletContext(ServletContext context) {
        this.servletContext = context;
    }
}