FormBeanUser


1   /*
2    * $Id: FormBeanUser.java,v 1.7 2003/10/27 11:00:38 thusted Exp $
3    * $Source: /cvsroot/mav/maverick/src/java/org/infohazard/maverick/ctl/FormBeanUser.java,v $
4    */
5   
6   package org.infohazard.maverick.ctl;
7   
8   import org.infohazard.maverick.flow.*;
9   import org.apache.commons.beanutils.BeanUtils;
10  import org.jdom.Element;
11  import javax.servlet.*;
12  
13  /**
14   * FormBeanUser is a base class for singleton controllers which use
15   * external FormBeans rather than populating themselves.  Since
16   * only one of these will exist for each command definition,
17   * it must be thread-safe.  This Controller pattern is very similar
18   * to Struts Actions.
19   */
20  public abstract class FormBeanUser implements ControllerSingleton
21  {
22      /**
23       * Common name for the typical "success" view.
24       */
25      public static final String   SUCCESS = "success";
26  
27      /**
28       * Common name for the typical "error" view.
29       */
30      public static final String   ERROR = "error";
31  
32      /**
33       * If you want any custom behavior based on the content of the
34       * configuration file, this will be called once before the
35       * FormBeanUser is ever used.
36       *
37       * @see ControllerSingleton#init
38       */
39      public void init(Element controllerNode) throws ConfigException
40      {
41          // Defaults to nothing.
42      }
43  
44      /**
45       * Executes this controller.  Override one of the other perform()
46       * methods to provide application logic.
47       *
48       * @see ControllerSingleton#go
49       */
50      public final String   go(ControllerContext cctx) throws ServletException
51      {
52          try
53          {
54              Object   formBean = this.makeFormBean(cctx);
55              
56              BeanUtils.populate(formBean, cctx.getRequest().getParameterMap());
57              BeanUtils.populate(formBean, cctx.getControllerParams());
58              
59              cctx.setModel(formBean);
60  
61              return this.perform(formBean, cctx);
62          }
63          catch (ServletException ex)
64          {
65              throw ex;
66          }
67          catch (Exception   ex)
68          {
69              throw new ServletException(ex);
70          }
71      }
72  
73      /**
74       * This method can be overriden to perform application logic.
75       *
76       * Override this method if you want the model to be something
77       * other than the formBean itself.
78       *
79       * @param formBean will be a bean created by makeFormBean(),
80       * which has been populated with the http request parameters.
81       */
82      protected String   perform(Object   formBean, ControllerContext cctx) throws Exception  
83      {
84          return SUCCESS;
85      }
86                                                  
87      /**
88       * This method will be called to produce a simple bean whose properties
89       * will be populated with the http request parameters.  The parameters
90       * are useful for doing things like persisting beans across requests.
91       */
92      protected abstract Object   makeFormBean(ControllerContext cctx);
93  }
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