org.apache.commons.digester.substitution.MultiVariableExpander Maven / Gradle / Ivy
/* $Id: MultiVariableExpander.java 729129 2008-12-23 21:27:42Z rahul $
*
* 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.
*/
package org.apache.commons.digester.substitution;
import java.util.Map;
import java.util.ArrayList;
/**
* Expands variable references from multiple sources.
*
* @since 1.6
*/
public class MultiVariableExpander implements VariableExpander {
private int nEntries = 0;
private ArrayList markers = new ArrayList(2);
private ArrayList> sources = new ArrayList>(2);
public MultiVariableExpander() {
}
public void addSource(String marker, Map source) {
++nEntries;
markers.add(marker);
sources.add(source);
}
/*
* Expands any variable declarations using any of the known
* variable marker strings.
*
* @throws IllegalArgumentException if the input param references
* a variable which is not known to the specified source.
*/
public String expand(String param) {
for(int i=0; i
* Commonly, the variable marker is "$", in which case variables
* are indicated by ${key} in the string.
*
* Returns the string after performing all substitutions.
*
* If no substitutions were made, the input string object is
* returned (not a copy).
*
* @throws IllegalArgumentException if the input param references
* a variable which is not known to the specified source.
*/
public String expand(String str, String marker, Map source) {
String startMark = marker + "{";
int markLen = startMark.length();
int index = 0;
for(;;)
{
index = str.indexOf(startMark, index);
if (index == -1)
{
return str;
}
int startIndex = index + markLen;
if (startIndex > str.length())
{
throw new IllegalArgumentException(
"var expression starts at end of string");
}
int endIndex = str.indexOf("}", index + markLen);
if (endIndex == -1)
{
throw new IllegalArgumentException(
"var expression starts but does not end");
}
String key = str.substring(index+markLen, endIndex);
Object value = source.get(key);
if (value == null) {
throw new IllegalArgumentException(
"parameter [" + key + "] is not defined.");
}
String varValue = value.toString();
str = str.substring(0, index) + varValue + str.substring(endIndex+1);
index += varValue.length();
}
}
}