1 package org.apache.commons.digester3.examples.plugins.pipeline;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership.
7 * The ASF licenses this file to You under the Apache License, Version 2.0
8 * (the "License"); you may not use this file except in compliance with
9 * the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19
20 import org.apache.commons.digester3.Digester;
21
22 /**
23 * An implementation of the Transform interface which replaces all occurrences
24 * of a specified string with a different string.
25 * <p>
26 * Because this class wishes to configure instances via nested "from" and
27 * "to" tags, it needs to define an addRules method to add rules to the
28 * Digester dynamically. Note that there are different ways of defining the
29 * rules though; for example they can be defined in a separate
30 * SubstituteTransformRuleInfo class.
31 */
32 public class SubstituteTransform
33 implements Transform
34 {
35
36 private String from;
37
38 private String to;
39
40 public void setFrom( String from )
41 {
42 this.from = from;
43 }
44
45 public void setTo( String to )
46 {
47 this.to = to;
48 }
49
50 public String transform( String s )
51 {
52 StringBuilder buf = new StringBuilder( s );
53 while ( true )
54 {
55 int idx = buf.indexOf( from );
56 if ( idx == -1 )
57 {
58 break;
59 }
60
61 buf.replace( idx, idx + from.length(), to );
62 }
63 return buf.toString();
64 }
65
66 public static void addRules( Digester d, String patternPrefix )
67 {
68 d.addCallMethod( patternPrefix + "/from", "setFrom", 0 );
69 d.addCallMethod( patternPrefix + "/to", "setTo", 0 );
70 }
71
72 }