/*
* 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.tools.ant.filters;
import java.io.IOException;
import java.io.Reader;
import java.util.Properties;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.PropertyHelper;
import org.apache.tools.ant.property.GetProperty;
import org.apache.tools.ant.property.ParseProperties;
import org.apache.tools.ant.types.PropertySet;
/**
* Expands Ant properties, if any, in the data.
* <p>
* Example:<br>
* <pre><expandproperties/></pre>
* Or:
* <pre><filterreader
* classname="org.apache.tools.ant.filters.ExpandProperties"/></pre>
*
*/
public final class ExpandProperties
extends BaseFilterReader
implements ChainableReader {
private static final int EOF = -1;
private char[] buffer;
private int index;
private PropertySet propertySet;
/**
* Constructor for "dummy" instances.
*
* @see BaseFilterReader#BaseFilterReader()
*/
public ExpandProperties() {
super();
}
/**
* Creates a new filtered reader.
*
* @param in A Reader object providing the underlying stream.
* Must not be <code>null</code>.
*/
public ExpandProperties(final Reader in) {
super(in);
}
/**
* Restrict the expanded properties using a PropertySet.
* @param propertySet replacement lookup
*/
public void add(PropertySet propertySet) {
if (this.propertySet != null) {
throw new BuildException("expandproperties filter accepts only one propertyset");
}
this.propertySet = propertySet;
}
/**
* Returns the next character in the filtered stream. The original
* stream is first read in fully, and the Ant properties are expanded.
* The results of this expansion are then queued so they can be read
* character-by-character.
*
* @return the next character in the resulting stream, or -1
* if the end of the resulting stream has been reached
*
* @exception IOException if the underlying stream throws an IOException
* during reading
*/
public int read() throws IOException {
if (index > EOF) {
if (buffer == null) {
String data = readFully();
Project project = getProject();
GetProperty getProperty;
if (propertySet == null) {
getProperty = PropertyHelper.getPropertyHelper(project);
} else {
final Properties props = propertySet.getProperties();
getProperty = new GetProperty() {
public Object getProperty(String name) {
return props.getProperty(name);
}
};
}
buffer = new ParseProperties(project, PropertyHelper.getPropertyHelper(project)
.getExpanders(), getProperty).parseProperties(data).toString()
.toCharArray();
}
if (index < buffer.length) {
return buffer[index++];
}
index = EOF;
}
return EOF;
}
/**
* Creates a new ExpandProperties filter using the passed in
* Reader for instantiation.
*
* @param rdr A Reader object providing the underlying stream.
* Must not be <code>null</code>.
*
* @return a new filter based on this configuration, but filtering
* the specified reader
*/
public Reader chain(final Reader rdr) {
ExpandProperties newFilter = new ExpandProperties(rdr);
newFilter.setProject(getProject());
newFilter.add(propertySet);
return newFilter;
}
}