performbooknewsaudaction.java

beginJsp2.0外文书籍源代码

package com.wrox.publish.action;

import com.wrox.publish.bo.ActionDeniedException;
import com.wrox.publish.bo.BookBO;
import com.wrox.publish.om.BookNews;

import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.LookupDispatchAction;

/**
 * Struts Action invoked when the user wants to add, update or delete
 * a BookNews item in the database. The form button pressed determines 
 * the method the request is dispatched to.
 */
public class PerformBookNewsAUDAction extends LookupDispatchAction {
    /** 
     * Used by the superclass to determine which methods should be
     * called in response to which buttons.
     * @return A Map mapping button labels to the method name to invoke.
     */    
    protected Map getKeyMethodMap() {
        Map map = new HashMap();
        map.put("booknews.add.button.label", "add");
        map.put("booknews.update.button.label", "update");
        map.put("booknews.delete.button.label", "delete");
        return map;
    }

    /** 
     * Invoked by the Struts controller. This method is overridden to detect
     * the use of the Cancel button; in that case the ActionForward labelled
     * "cancel" is returned.
     * @param mapping The ActionMapping invoking this Action.
     * @param form The ActionForm. This <em>must</em> be a BookNews item.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @return the ActionForward identifying where to go next.
     * @throws Exception if an error occurred.
     */    
    public ActionForward execute(ActionMapping mapping, 
                                 ActionForm form,
                                 HttpServletRequest request, 
                                 HttpServletResponse response) 
    throws Exception {
        if (request.getParameterMap().containsKey("id") ||
            request.getParameterMap().containsKey("user") ||
            request.getParameterMap().containsKey("published")) {
            request.getSession().removeAttribute(mapping.getName());
            throw new ActionDeniedException(
                    "id, user and published are immutable");
        }
        if (isCancelled(request)) {
            return mapping.findForward("cancel");
        } else {
            return super.execute(mapping, form, request, response);
        }
    }
    
    /** 
     * Invoked by the superclass' dispatcher code when Add was pressed.
     * @param mapping The ActionMapping invoking this Action.
     * @param form The ActionForm. This <em>must</em> be a BookNews item.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @return the ActionForward item labelled "added".
     * @throws Exception if an error occurred.
     */    
    public ActionForward add(ActionMapping mapping, 
                             ActionForm form,
                             HttpServletRequest request, 
                             HttpServletResponse response) 
    throws Exception {
        BookBO bookBO = BookBO.getInstance(request, getDataSource(request));
        bookBO.create((BookNews)form);
        return mapping.findForward("added");
    }

    /** 
     * Invoked by the superclass' dispatcher code when Update was pressed.
     * @param mapping The ActionMapping invoking this Action.
     * @param form The ActionForm. This <em>must</em> be a BookNews item.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @return the ActionForward item labelled "updated".
     * @throws Exception if an error occurred.
     */    
    public ActionForward update(ActionMapping mapping, 
                                ActionForm form,
                                HttpServletRequest request, 
                                HttpServletResponse response) 
    throws Exception {
        BookBO bookBO = BookBO.getInstance(request, getDataSource(request));
        bookBO.update((BookNews)form);
        return mapping.findForward("updated");
    }

    /** 
     * Invoked by the superclass' dispatcher code when Delete was pressed.
     * @param mapping The ActionMapping invoking this Action.
     * @param form The ActionForm. This <em>must</em> be a BookNews item.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @return the ActionForward item labelled "deleted".
     * @throws Exception if an error occurred.
     */    
    public ActionForward delete(ActionMapping mapping, 
                                ActionForm form,
                                HttpServletRequest request, 
                                HttpServletResponse response) 
    throws Exception {
        BookBO bookBO = BookBO.getInstance(request, getDataSource(request));
        bookBO.remove((BookNews)form);
        return mapping.findForward("deleted");
    }
}