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Java > Open Source Codes > org > apache > commons > betwixt > io > read > MappingAction


1 /*
2  * Copyright 2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.betwixt.io.read;
17
18 import org.apache.commons.betwixt.AttributeDescriptor;
19 import org.apache.commons.betwixt.ElementDescriptor;
20 import org.xml.sax.Attributes JavaDoc;
21
22 /**
23  * Executes mapping action for a subgraph.
24  * It is intended that most MappingAction's will not need to maintain state.
25  *
26  * @author <a HREF='http://jakarta.apache.org/'>Jakarta Commons Team</a>
27  * @version $Revision: 1.2 $
28  */
29 public abstract class MappingAction {
30
31        
32     public abstract MappingAction next(
33         String JavaDoc namespace,
34         String JavaDoc name,
35         Attributes JavaDoc attributes,
36         ReadContext context)
37         throws Exception JavaDoc;
38
39     /**
40      * Executes mapping action on new element.
41      * @param namespace
42      * @param name
43      * @param attributes Attributes not null
44      * @param context Context not null
45      * @return the MappingAction to be used to map the sub-graph
46      * under this element
47      * @throws Exception
48      */
49     public abstract MappingAction begin(
50         String JavaDoc namespace,
51         String JavaDoc name,
52         Attributes JavaDoc attributes,
53         ReadContext context)
54         throws Exception JavaDoc;
55
56     /**
57      * Executes mapping action for element body text
58      * @param text
59      * @param context
60      * @throws Exception
61      */
62     public abstract void body(String JavaDoc text, ReadContext context)
63         throws Exception JavaDoc;
64
65     /**
66      * Executes mapping action one element ends
67      * @param context
68      * @throws Exception
69      */
70     public abstract void end(ReadContext context) throws Exception JavaDoc;
71
72     public static final MappingAction EMPTY = new MappingAction.Base();
73
74     public static final MappingAction IGNORE = new MappingAction.Ignore();
75     
76     private static final class Ignore extends MappingAction {
77
78         public MappingAction next(String JavaDoc namespace, String JavaDoc name, Attributes JavaDoc attributes, ReadContext context) throws Exception JavaDoc {
79             return this;
80         }
81
82         public MappingAction begin(String JavaDoc namespace, String JavaDoc name, Attributes JavaDoc attributes, ReadContext context) throws Exception JavaDoc {
83             return this;
84         }
85
86         public void body(String JavaDoc text, ReadContext context) throws Exception JavaDoc {
87             // do nothing
88 }
89
90         public void end(ReadContext context) throws Exception JavaDoc {
91             // do nothing
92 }
93         
94     }
95
96     /**
97      * Basic action.
98      *
99      * @author <a HREF='http://jakarta.apache.org/'>Jakarta Commons Team</a>
100      * @version $Revision: 1.2 $
101      */
102     public static class Base extends MappingAction {
103         
104         public MappingAction next(
105             String JavaDoc namespace,
106             String JavaDoc name,
107             Attributes JavaDoc attributes,
108             ReadContext context)
109             throws Exception JavaDoc {
110         
111             return context.getActionMappingStrategy().getMappingAction(namespace, name, attributes, context);
112         }
113         
114         /* (non-Javadoc)
115          * @see org.apache.commons.betwixt.io.read.MappingAction#begin(java.lang.String, java.lang.String, org.xml.sax.Attributes, org.apache.commons.betwixt.io.read.ReadContext, org.apache.commons.betwixt.XMLIntrospector)
116          */
117         public MappingAction begin(
118             String JavaDoc namespace,
119             String JavaDoc name,
120             Attributes JavaDoc attributes,
121             ReadContext context)
122             throws Exception JavaDoc {
123             // TODO: i'm not too sure about this part of the design
124 // i'm not sure whether base should give base behaviour or if it should give standard behaviour
125 // i'm hoping that things will become clearer once the descriptor logic has been cleared
126 ElementDescriptor descriptor = context.getCurrentDescriptor();
127             if (descriptor != null) {
128
129                 AttributeDescriptor[] attributeDescriptors =
130                     descriptor.getAttributeDescriptors();
131                 context.populateAttributes(attributeDescriptors, attributes);
132             }
133             return this;
134         }
135
136         /* (non-Javadoc)
137          * @see org.apache.commons.betwixt.io.read.MappingAction#body(java.lang.String, org.apache.commons.betwixt.io.read.ReadContext, org.apache.commons.betwixt.XMLIntrospector)
138          */
139         public void body(String JavaDoc text, ReadContext context) throws Exception JavaDoc {
140             // do nothing
141 }
142
143         /* (non-Javadoc)
144          * @see org.apache.commons.betwixt.io.read.MappingAction#end(org.apache.commons.betwixt.io.read.ReadContext, org.apache.commons.digester.Digester, org.apache.commons.betwixt.XMLIntrospector)
145          */
146         public void end(ReadContext context) throws Exception JavaDoc {
147             // do nothing
148 // TODO: this is a temporary refactoring
149 // it would be better to do this in the rule
150 // need to move more logic into the context and out of the rule
151 context.popElement();
152         }
153
154     }
155 }
156
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