ActionHandler


1   package org.jahia.utils;
2   
3   import java.io.FileInputStream  ;
4   import java.io.IOException  ;
5   import java.lang.reflect.InvocationTargetException  ;
6   import java.lang.reflect.Method  ;
7   import java.util.Properties  ;
8   
9   import javax.servlet.http.HttpServletRequest  ;
10  import javax.servlet.http.HttpServletResponse  ;
11  
12  
13  /**
14   * Class ActionHandler: determines the method to invoke for an Application
15   * (typically a Web Application), given an action.
16   *
17   * @author  Stephane Boury, Jerome Tamiotti
18   * @version 1.1
19   */
20  public class ActionHandler {
21  
22      private static org.apache.log4j.Logger logger =
23              org.apache.log4j.Logger.getLogger(ActionHandler.class);
24  
25      /* The class on which to call the methods */
26      private Class   actionClass;
27  
28      /**
29       * An instance of the class on which to call the methods
30       * This instance is null here because the class is static,
31       * and the parameter of 'invokeMethod' method will be ignored
32       */
33      private Object   instanceOfClass = null;
34  
35  
36      /* The hashtable containing the method names */
37      private Properties   methods;
38  
39      /**
40       * Class constructor: builds the hashtable by reading a flat file.
41       *
42       * @param propsFile     the full path to the file containing pairs of
43       * "action - method name"
44       * @param theClass      the name of the Class on which to call the methods
45       */
46      public ActionHandler(String   propsFile, String   theClass) {
47  
48          methods = new Properties  ();
49          try {
50              FileInputStream   fis = new FileInputStream  (propsFile);
51              methods.load(fis);
52              fis.close();
53          }
54          catch (IOException   e) {
55              logger.error("ActionHandler-ActionHandler", e);
56          }
57  
58          try {
59              actionClass = Class.forName(theClass);
60          } catch (ClassNotFoundException   ex) {
61              logger.error("ActionHandler-ActionHandler", ex);
62          } catch (Exception   ex) {
63              logger.error("ActionHandler-ActionHandler", ex);
64          }
65      }
66  
67      /**
68       * Calls the appropriate method given the action.
69       *
70       * @param action    the action that triggers the method to call
71       * @param request   the request parameter for the method
72       */
73      public Object   call(String   action, HttpServletRequest   request) throws NullPointerException   {
74  
75          String   theMethod = methods.getProperty(action);
76          if (theMethod == null) { //method not found in list
77              logger.error("No method found for action " + action);
78              throw new NullPointerException  ();
79          }
80          try {
81              Class   theParams[] = {Class.forName("javax.servlet.http.HttpServletRequest")};
82              Method   thisMethod = actionClass.getDeclaredMethod(theMethod, theParams);
83              Object   args[] = {request};
84              return thisMethod.invoke(instanceOfClass, args);
85  
86          } catch(ClassNotFoundException   cnfe) {
87              logger.error("ActionHandler-call", cnfe);
88              throw new NullPointerException  ();
89  
90          } catch(NoSuchMethodException   nsme) {
91              logger.error("ActionHandler-call", nsme);
92              throw new NullPointerException  ();
93  
94          } catch(IllegalAccessException   iae) {
95              logger.error("ActionHandler-call", iae);
96              throw new NullPointerException  ();
97  
98          } catch(InvocationTargetException   ite) {
99              logger.error("Target exception", ite.getTargetException());
100             logger.error("ActionHandler-call", ite);
101 
102             throw new NullPointerException  ();
103         }
104     }
105 
106 
107     /**
108      * Calls the appropriate method given the action.
109      *
110      * @param action     the action that triggers the method to call
111      * @param request    the request parameter for the method
112      * @param response   the response parameter for the method
113      */
114     public Object   call( Object   instanceOfClass, String   action, HttpServletRequest   request, HttpServletResponse   response) throws NullPointerException   {
115 
116         String   theMethod = methods.getProperty(action);
117         if (theMethod == null) { //method not found in list
118             logger.error("No method found for action " + action);
119             throw new NullPointerException  ();
120         }
121         try {
122             Class   theParams[] = {Class.forName("javax.servlet.http.HttpServletRequest"),Class.forName("javax.servlet.http.HttpServletResponse")};
123             Method   thisMethod = actionClass.getDeclaredMethod(theMethod, theParams);
124             Object   args[] = {request,response};
125 
126             return thisMethod.invoke(instanceOfClass, args);
127 
128         } catch(ClassNotFoundException   cnfe) {
129             logger.error("Class not found", cnfe);
130             throw new NullPointerException  ();
131 
132         } catch(NoSuchMethodException   nsme) {
133             logger.error("No such method", nsme);
134             throw new NullPointerException  ();
135 
136         } catch(IllegalAccessException   iae) {
137             logger.error("Illegal access exception", iae);
138             throw new NullPointerException  ();
139 
140         } catch(InvocationTargetException   ite) {
141             logger.error("Invocation error", ite);
142             if (ite.getTargetException() != null) {
143                 logger.error("Root cause", ite.getTargetException());
144             }
145             throw new NullPointerException  ();
146         }
147     }
148 
149 }
150
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