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Java > Open Source Codes > org > apache > velocity > context > InternalContextBase


1 package org.apache.velocity.context;
2
3 /*
4  * Copyright 2001,2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import java.util.HashMap JavaDoc;
20 import java.util.Stack JavaDoc;
21 import java.io.Serializable JavaDoc;
22
23 import org.apache.velocity.util.introspection.IntrospectionCacheData;
24
25 import org.apache.velocity.app.event.EventCartridge;
26 import org.apache.velocity.runtime.resource.Resource;
27
28 /**
29  * class to encapsulate the 'stuff' for internal operation of velocity.
30  * We use the context as a thread-safe storage : we take advantage of the
31  * fact that it's a visitor of sorts to all nodes (that matter) of the
32  * AST during init() and render().
33  * Currently, it carries the template name for namespace
34  * support, as well as node-local context data introspection caching.
35  *
36  * Note that this is not a public class. It is for package access only to
37  * keep application code from accessing the internals, as AbstractContext
38  * is derived from this.
39  *
40  * @author <a HREF="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
41  * @version $Id: InternalContextBase.java,v 1.8.12.1 2004/03/03 23:22:54 geirm Exp $
42  */
43 class InternalContextBase implements InternalHousekeepingContext, InternalEventContext, Serializable JavaDoc
44 {
45     /**
46      * cache for node/context specific introspection information
47      */
48     private HashMap JavaDoc introspectionCache = new HashMap JavaDoc(33);
49     
50     /**
51      * Template name stack. The stack top contains the current template name.
52      */
53     private Stack JavaDoc templateNameStack = new Stack JavaDoc();
54
55     /**
56      * EventCartridge we are to carry. Set by application
57      */
58     private EventCartridge eventCartridge = null;
59
60     /**
61      * Current resource - used for carrying encoding and other
62      * information down into the rendering process
63      */
64     private Resource currentResource = null;
65
66     /**
67      * set the current template name on top of stack
68      *
69      * @param s current template name
70      */
71     public void pushCurrentTemplateName( String JavaDoc s )
72     {
73         templateNameStack.push(s);
74         return;
75     }
76
77     /**
78      * remove the current template name from stack
79      */
80     public void popCurrentTemplateName()
81     {
82         templateNameStack.pop();
83         return;
84     }
85      
86     /**
87      * get the current template name
88      *
89      * @return String current template name
90      */
91     public String JavaDoc getCurrentTemplateName()
92     {
93         if ( templateNameStack.empty() )
94             return "<undef>";
95         else
96             return (String JavaDoc) templateNameStack.peek();
97     }
98
99     /**
100      * get the current template name stack
101      *
102      * @return Object[] with the template name stack contents.
103      */
104     public Object JavaDoc[] getTemplateNameStack()
105     {
106         return templateNameStack.toArray();
107     }
108
109     /**
110      * returns an IntrospectionCache Data (@see IntrospectionCacheData)
111      * object if exists for the key
112      *
113      * @param key key to find in cache
114      * @return cache object
115      */
116     public IntrospectionCacheData icacheGet( Object JavaDoc key )
117     {
118         return ( IntrospectionCacheData ) introspectionCache.get( key );
119     }
120      
121     /**
122      * places an IntrospectionCache Data (@see IntrospectionCacheData)
123      * element in the cache for specified key
124      *
125      * @param key key
126      * @param o IntrospectionCacheData object to place in cache
127      */
128     public void icachePut( Object JavaDoc key, IntrospectionCacheData o )
129     {
130         introspectionCache.put( key, o );
131     }
132
133     public void setCurrentResource( Resource r )
134     {
135         currentResource = r;
136     }
137
138     public Resource getCurrentResource()
139     {
140         return currentResource;
141     }
142
143     public EventCartridge attachEventCartridge( EventCartridge ec )
144     {
145         EventCartridge temp = eventCartridge;
146
147         eventCartridge = ec;
148         
149         return temp;
150     }
151
152     public EventCartridge getEventCartridge()
153     {
154         return eventCartridge;
155     }
156 }
157
158
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