1 package net.sf.logdistiller.util;
2
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
17 import java.util.Map;
18
19 /**
20 * A small utility to replace properties within strings (syntax: <code>${<i>name</i>}</code>).
21 */
22 public class PropertiesReplacer
23 {
24 private final String beginMark;
25
26 private final String endMark;
27
28 private final Map<String, String> properties;
29
30 public PropertiesReplacer( Map<String, String> properties, String beginMark, String endMark )
31 {
32 this.properties = properties;
33 this.beginMark = beginMark;
34 this.endMark = endMark;
35 }
36
37 public PropertiesReplacer( Map<String, String> properties )
38 {
39 this( properties, "${", "}" );
40 }
41
42 /**
43 * Replace <code>${<i>name</i>}</code> by the value of the property.
44 *
45 * @param source String the string to interpret (or <code>null</code>)
46 * @return String the transformed string
47 * @throws IllegalArgumentException if the source string references an inexistent property
48 */
49 public String replaceProperties( String source )
50 {
51 if ( source == null )
52 {
53 return null;
54 }
55 int index = 0;
56 int nextBegin, nextEnd;
57 StringBuffer buff = new StringBuffer();
58 while ( ( ( nextBegin = source.indexOf( beginMark, index ) ) >= 0 )
59 && ( ( nextEnd = source.indexOf( endMark, nextBegin ) ) >= 0 ) )
60 {
61 String name = source.substring( nextBegin + 2, nextEnd );
62 String value = properties.get( name );
63 if ( value == null )
64 {
65 throw new IllegalArgumentException( "unknown property '" + name + "'" );
66 }
67 buff.append( source.substring( index, nextBegin ) );
68 buff.append( value );
69 index = nextEnd + 1;
70 }
71 if ( index == 0 )
72 {
73 // little optimization...
74 return source;
75 }
76 buff.append( source.substring( index ) );
77 return buff.toString();
78 }
79 }