usemenudisplayertag.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

package net.sf.navigator.taglib;

import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import net.sf.navigator.displayer.MenuDisplayer;
import net.sf.navigator.displayer.MenuDisplayerMapping;
import net.sf.navigator.displayer.MessageResourcesMenuDisplayer;
import net.sf.navigator.menu.MenuRepository;
import net.sf.navigator.menu.PermissionsAdapter;
import net.sf.navigator.menu.RolesPermissionsAdapter;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.Globals;
import org.apache.struts.util.MessageResources;


/**
 * This is the main tag of Struts Menu and can be used in a JSP as follows:</p>
 * <pre>
 *  &lt;menu:useMenuDisplayer name="ListMenu"&gt;
 *     &lt;menu:displayMenu name="MyMenu"/&gt;
 *  &lt;/menu:useMenuDisplayer&gt;
 * </pre>
 * 
 * @author  ssayles, mraible
 * @version $Revision: 1.11 $ $Date: 2004/03/23 16:50:37 $
 */
public class UseMenuDisplayerTag extends TagSupport {
    //~ Static fields/initializers =============================================

    private static Log log = LogFactory.getLog(UseMenuDisplayerTag.class);

    /**
     * Variable used by this Tag to expose the repository to the
     * {@link DisplayMenuTag}.
     */
    protected static final String PRIVATE_REPOSITORY =
            "net.sf.navigator.repositoryKey";

    public static final String DISPLAYER_KEY =
            "net.sf.navigator.taglib.DISPLAYER";

    public static final String ROLES_ADAPTER = "rolesAdapter";
    
    protected static ResourceBundle messages =
            ResourceBundle.getBundle("net.sf.navigator.taglib.LocalStrings");

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

    protected MenuDisplayer menuDisplayer;
    protected String localeKey;
    protected String name;
    protected String bundleKey;
    private String config = MenuDisplayer.DEFAULT_CONFIG;
    private String permissions;
    private String repository;
    protected ResourceBundle rb; // used to allow setting of ResourceBundle 
                                 // from JSTL in EL tag

    //~ Methods ================================================================

    public String getBundle() {
        return bundleKey;
    }

    public void setBundle(String bundle) {
        this.bundleKey = bundle;
    }

    public String getConfig() {
        return config;
    }

    public void setConfig(String config) {
        if (log.isDebugEnabled()) {
            log.debug("setting config to: " + config);
        }

        this.config = config;
    }

    public String getLocale() {
        return localeKey;
    }

    public void setLocale(String locale) {
        this.localeKey = locale;
    }

    public String getName() {
        return name;
    }

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

    public String getRepository() {
        return repository;
    }

    /**
     * This method allows users to override the key used to lookup the
     * repository.  If not specified - the default repository is used, which is
     * "net.sf.navigator.MENU_REPOSITORY" or
     * UseMenuDisplayerTag.MENU_REPOSITORY_KEY.
     * @param repository
     */
    public void setRepository(String repository) {
        this.repository = repository;
    }

    /** Getter for property permissions.
     * @return Value of property permissions.
     */
    public String getPermissions() {
        return this.permissions;
    }

    /** Setter for property permissions.
     * @param permissions New value of property permissions.
     */
    public void setPermissions(String permissions) {
        this.permissions = permissions;
    }

    public int doStartTag() throws JspException {
        if (repository == null) {
            repository = MenuRepository.MENU_REPOSITORY_KEY;
        }

        if (log.isDebugEnabled()) {
            log.debug("Looking for repository named '" + repository + "'");
        }

        // get the menu repository
        MenuRepository rep =
            (MenuRepository) pageContext.findAttribute(this.repository);

        if (rep == null) {
            throw new JspException(messages.getString("menurepository.not.found"));
        } else {
            // set repository as a pageContext variable so that DisplayMenuTag
            // can grab it.
            if (log.isDebugEnabled()) {
                log.debug("stuffing repository into pageContext...");
            }
            pageContext.setAttribute(PRIVATE_REPOSITORY, rep);
        }

        //get the displayer mapping
        MenuDisplayerMapping displayerMapping =
                rep.getMenuDisplayerMapping(this.name);

        if (displayerMapping == null) {
            throw new JspException(messages.getString("displayer.mapping.not.found"));
        }

        PermissionsAdapter permissions = getPermissionsAdapter();

        //get an instance of the menu displayer
        MenuDisplayer displayerInstance = null;

        try {
            displayerInstance =
                    (MenuDisplayer) Class.forName(displayerMapping.getType())
                    .newInstance();
            menuDisplayer = displayerInstance;
            // default to use the config on the mapping
            if (displayerMapping.getConfig() != null) {
                // this value (config) is set on the displayer below
                setConfig(displayerMapping.getConfig());
            }
        } catch (Exception e) {
            throw new JspException(e.getMessage());
        }
        
        if (bundleKey == null) {
        	this.bundleKey = Globals.MESSAGES_KEY;
        }
        
        // setup the displayerInstance
        // if the displayer is a MessageResourceMenuDisplayer
        // and a bundle is specified, then pass it the bundle (message resources) and
        // the locale
        if ((bundleKey != null) &&
                (displayerInstance instanceof MessageResourcesMenuDisplayer)) {
            MessageResourcesMenuDisplayer mrDisplayerInstance =
                    (MessageResourcesMenuDisplayer) displayerInstance;
            Locale locale = null;

            if (localeKey == null) {
                // default to Struts locale
                locale = 
                    (Locale) pageContext.findAttribute(Globals.LOCALE_KEY);
                if (locale == null) {
                	locale = pageContext.getRequest().getLocale();
                }
            } else {
                locale = (Locale) pageContext.findAttribute(localeKey);
            }
            mrDisplayerInstance.setLocale(locale);
            
            if (rb != null) {
                mrDisplayerInstance.setMessageResources(rb);
            } else {
                MessageResources resources =
                    (MessageResources) pageContext.findAttribute(bundleKey);
                
                if (resources == null) {
                    // try a simple ResourceBundle
                    try {
                    	rb = ResourceBundle.getBundle(bundleKey, locale);
                        mrDisplayerInstance.setMessageResources(rb);
                    } catch (MissingResourceException mre) {
                    	log.error(mre.getMessage());
                    }
                } else {
                     mrDisplayerInstance.setMessageResources(resources);   
                }
            }
        }

        displayerInstance.setConfig(config);

        displayerInstance.init(pageContext, displayerMapping);
        displayerInstance.setPermissionsAdapter(permissions);

        pageContext.setAttribute(DISPLAYER_KEY, displayerInstance);

        //make the menu repository available to the menu displayers
        //pageContext.setAttribute(MENU_REPOSITORY_KEY, menuRep);
        return (EVAL_BODY_INCLUDE);
    }

    protected PermissionsAdapter getPermissionsAdapter()
            throws JspException {
        PermissionsAdapter adapter = null;

        if (permissions != null) {
            // If set to "rolesAdapter", then create automatically
            if (permissions.equalsIgnoreCase(ROLES_ADAPTER)) {
                adapter =
                    new RolesPermissionsAdapter((HttpServletRequest) pageContext.getRequest());
            } else {
                adapter =
                    (PermissionsAdapter) pageContext.findAttribute(permissions);

                if (adapter == null) {
                    throw new JspException(messages.getString("permissions.not.found"));
                }
            }
        }

        return adapter;
    }

    public int doEndTag() throws JspException {
        menuDisplayer.end(pageContext);
        pageContext.removeAttribute(DISPLAYER_KEY);
        pageContext.removeAttribute(PRIVATE_REPOSITORY);
        // Might have to apply fix for
        // http://nagoya.apache.org/bugzilla/show_bug.cgi?id=16001
        // release(); // don't seem to need it at this point...
        return (EVAL_PAGE);
    }

    public void release() {
        if (log.isDebugEnabled()) {
            log.debug("release() called");
        }

        this.menuDisplayer = null;
        this.bundleKey = null;
        this.config = MenuDisplayer.DEFAULT_CONFIG;
        this.localeKey = null;
        this.name = null;
        this.menuDisplayer = null;
        this.repository = null;
        this.permissions = null;
        this.rb = null;
    }
}