Commons Digester example source code file (SubstituteTransform.java)

This example Commons Digester source code file (SubstituteTransform.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Digester tags/keywords

string, string, stringbuffer, stringbuffer, substitutetransform, substitutetransform, transform, transform

The Commons Digester SubstituteTransform.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 

import org.apache.commons.digester.Digester;

/**
 * An implementation of the Transform interface which replaces all occurrences
 * of a specified string with a different string.
 * <p>
 * Because this class wishes to configure instances via nested "from" and
 * "to" tags, it needs to define an addRules method to add rules to the
 * Digester dynamically. Note that there are different ways of defining the
 * rules though; for example they can be defined in a separate
 * SubstituteTransformRuleInfo class.
 */
 
public class SubstituteTransform implements Transform {
    private String from;
    private String to;
    
    public void setFrom(String from) {
        this.from = from;
    }
    
    public void setTo(String to) {
        this.to = to;
    }
    
    public String transform(String s) {
        StringBuffer buf = new StringBuffer(s);
        while (true) {
            int idx = buf.indexOf(from);
            if (idx == -1)
                break;
            
            StringBuffer buf2 = buf.replace(idx, idx+from.length(), to);
        }
        return buf.toString();
    }
    
    public static void addRules(Digester d, String patternPrefix) {
        d.addCallMethod(patternPrefix+"/from", "setFrom", 0);
        d.addCallMethod(patternPrefix+"/to", "setTo", 0);
    }
}