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Java > Open Source Codes > org > apache > commons > digester > Substitutor


1 /* $Id: Substitutor.java 155412 2005-02-26 12:58:36Z dirkv $
2  *
3  * Copyright 2003-2004 The Apache Software Foundation.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 package org.apache.commons.digester;
19
20 import org.xml.sax.Attributes JavaDoc;
21
22 /**
23  * <p>(Logical) Interface for substitution strategies.
24  * (It happens to be implemented as a Java abstract class to allow
25  * future additions to be made without breaking backwards compatibility.)
26  * </p>
27  * <p>
28  * Usage: When {@link Digester#setSubstitutor} is set, <code>Digester</code>
29  * calls the methods in this interface to create substitute values which will
30  * be passed into the Rule implementations.
31  * Of course, it is perfectly acceptable for implementations not to make
32  * substitutions and simply return the inputs.
33  * </p>
34  * <p>Different strategies are supported for attributes and body text.</p>
35  *
36  * @since 1.6
37  */
38 public abstract class Substitutor {
39     
40     /**
41      * <p>Substitutes the attributes (before they are passed to the
42      * <code>Rule</code> implementations's).</p>
43      *
44      * <p><code>Digester</code> will only call this method a second time
45      * once the original <code>Attributes</code> instance can be safely reused.
46      * The implementation is therefore free to reuse the same <code>Attributes</code> instance
47      * for all calls.</p>
48      *
49      * @param attributes the <code>Attributes</code> passed into <code>Digester</code> by the SAX parser,
50      * not null (but may be empty)
51      * @return <code>Attributes</code> to be passed to the <code>Rule</code> implementations.
52      * This method may pass back the Attributes passed in.
53      * Not null but possibly empty.
54      */
55     public abstract Attributes JavaDoc substitute(Attributes JavaDoc attributes);
56     
57     /**
58      * Substitutes for the body text.
59      * This method may substitute values into the body text of the
60      * elements that Digester parses.
61      *
62      * @param bodyText the body text (as passed to <code>Digester</code>)
63      * @return the body text to be passed to the <code>Rule</code> implementations
64      */
65     public abstract String JavaDoc substitute(String JavaDoc bodyText);
66 }
67
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