1 package org.apache.commons.digester3;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.xml.sax.Attributes;
23
24 /**
25 * <p>
26 * (Logical) Interface for substitution strategies. (It happens to be implemented as a Java abstract class to allow
27 * future additions to be made without breaking backwards compatibility.)
28 * </p>
29 * <p>
30 * Usage: When {@link Digester#setSubstitutor} is set, <code>Digester</code> calls the methods in this interface to
31 * create substitute values which will be passed into the Rule implementations. Of course, it is perfectly acceptable
32 * for implementations not to make substitutions and simply return the inputs.
33 * </p>
34 * <p>
35 * Different strategies are supported for attributes and body text.
36 * </p>
37 *
38 * @since 1.6
39 */
40 public abstract class Substitutor
41 {
42
43 /**
44 * <p>
45 * Substitutes the attributes (before they are passed to the <code>Rule</code> implementations's).
46 * </p>
47 * <p>
48 * <code>Digester</code> will only call this method a second time once the original <code>Attributes</code> instance
49 * can be safely reused. The implementation is therefore free to reuse the same <code>Attributes</code> instance for
50 * all calls.
51 * </p>
52 *
53 * @param attributes the <code>Attributes</code> passed into <code>Digester</code> by the SAX parser, not null (but
54 * may be empty)
55 * @return <code>Attributes</code> to be passed to the <code>Rule</code> implementations. This method may pass back
56 * the Attributes passed in. Not null but possibly empty.
57 */
58 public abstract Attributes substitute( Attributes attributes );
59
60 /**
61 * Substitutes for the body text. This method may substitute values into the body text of the elements that Digester
62 * parses.
63 *
64 * @param bodyText the body text (as passed to <code>Digester</code>)
65 * @return the body text to be passed to the <code>Rule</code> implementations
66 */
67 public abstract String substitute( String bodyText );
68
69 }