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Java > Open Source Codes > org > apache > commons > el > VariableResolverImpl


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55
56 package org.apache.commons.el;
57
58 import javax.servlet.jsp.PageContext JavaDoc;
59 import javax.servlet.jsp.el.VariableResolver JavaDoc;
60 import javax.servlet.jsp.el.ELException JavaDoc;
61
62 /**
63  *
64  * <p>This is the JSTL-specific implementation of VariableResolver.
65  * It looks up variable references in the PageContext, and also
66  * recognizes references to implicit objects.
67  *
68  * @author Nathan Abramson - Art Technology Group
69  * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
70  **/

71
72 public class VariableResolverImpl
73   implements VariableResolver JavaDoc
74 {
75   //-------------------------------------
76
// Member variables
77
//-------------------------------------
78

79   private PageContext JavaDoc mCtx;
80
81   //-------------------------------------
82
/**
83    *
84    * Constructor
85    **/

86   public VariableResolverImpl (PageContext JavaDoc pCtx)
87   {
88     mCtx = pCtx;
89   }
90   
91   //-------------------------------------
92
/**
93    *
94    * Resolves the specified variable within the given context.
95    * Returns null if the variable is not found.
96    **/

97   public Object JavaDoc resolveVariable (String JavaDoc pName)
98     throws ELException JavaDoc
99   {
100     // Check for implicit objects
101
if ("pageContext".equals (pName)) {
102       return mCtx;
103     }
104     else if ("pageScope".equals (pName)) {
105       return ImplicitObjects.
106     getImplicitObjects (mCtx).
107     getPageScopeMap ();
108     }
109     else if ("requestScope".equals (pName)) {
110       return ImplicitObjects.
111     getImplicitObjects (mCtx).
112     getRequestScopeMap ();
113     }
114     else if ("sessionScope".equals (pName)) {
115       return ImplicitObjects.
116     getImplicitObjects (mCtx).
117     getSessionScopeMap ();
118     }
119     else if ("applicationScope".equals (pName)) {
120       return ImplicitObjects.
121     getImplicitObjects (mCtx).
122     getApplicationScopeMap ();
123     }
124     else if ("param".equals (pName)) {
125       return ImplicitObjects.
126     getImplicitObjects (mCtx).
127     getParamMap ();
128     }
129     else if ("paramValues".equals (pName)) {
130       return ImplicitObjects.
131     getImplicitObjects (mCtx).
132     getParamsMap ();
133     }
134     else if ("header".equals (pName)) {
135       return ImplicitObjects.
136     getImplicitObjects (mCtx).
137     getHeaderMap ();
138     }
139     else if ("headerValues".equals (pName)) {
140       return ImplicitObjects.
141     getImplicitObjects (mCtx).
142     getHeadersMap ();
143     }
144     else if ("initParam".equals (pName)) {
145       return ImplicitObjects.
146     getImplicitObjects (mCtx).
147     getInitParamMap ();
148     }
149     else if ("cookie".equals (pName)) {
150       return ImplicitObjects.
151     getImplicitObjects (mCtx).
152     getCookieMap ();
153     }
154
155     // Otherwise, just look it up in the page context
156
else {
157       return mCtx.findAttribute (pName);
158     }
159   }
160                     
161   //-------------------------------------
162
}
163
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