/* * 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 org.apache.tools.ant.types.Parameter; /** * Attaches a prefix to every line. * * Example: *
<prefixlines prefix="Foo"/>* * Or: * *
<filterreader classname="org.apache.tools.ant.filters.PrefixLines"> * <param name="prefix" value="Foo"/> * </filterreader>* */ public final class PrefixLines extends BaseParamFilterReader implements ChainableReader { /** Parameter name for the prefix. */ private static final String PREFIX_KEY = "prefix"; /** The prefix to be used. */ private String prefix = null; /** Data that must be read from, if not null. */ private String queuedData = null; /** * Constructor for "dummy" instances. * * @see BaseFilterReader#BaseFilterReader() */ public PrefixLines() { super(); } /** * Creates a new filtered reader. * * @param in A Reader object providing the underlying stream. * Must not be
null
.
*/
public PrefixLines(final Reader in) {
super(in);
}
/**
* Returns the next character in the filtered stream. One line is read
* from the original input, and the prefix added. The resulting
* line is then used until it ends, at which point the next original line
* is read, etc.
*
* @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 (!getInitialized()) {
initialize();
setInitialized(true);
}
int ch = -1;
if (queuedData != null && queuedData.length() == 0) {
queuedData = null;
}
if (queuedData != null) {
ch = queuedData.charAt(0);
queuedData = queuedData.substring(1);
if (queuedData.length() == 0) {
queuedData = null;
}
} else {
queuedData = readLine();
if (queuedData == null) {
ch = -1;
} else {
if (prefix != null) {
queuedData = prefix + queuedData;
}
return read();
}
}
return ch;
}
/**
* Sets the prefix to add at the start of each input line.
*
* @param prefix The prefix to add at the start of each input line.
* May be null
, in which case no prefix
* is added.
*/
public void setPrefix(final String prefix) {
this.prefix = prefix;
}
/**
* Returns the prefix which will be added at the start of each input line.
*
* @return the prefix which will be added at the start of each input line
*/
private String getPrefix() {
return prefix;
}
/**
* Creates a new PrefixLines filter using the passed in
* Reader for instantiation.
*
* @param rdr A Reader object providing the underlying stream.
* Must not be null
.
*
* @return a new filter based on this configuration, but filtering
* the specified reader
*/
public Reader chain(final Reader rdr) {
PrefixLines newFilter = new PrefixLines(rdr);
newFilter.setPrefix(getPrefix());
newFilter.setInitialized(true);
return newFilter;
}
/**
* Initializes the prefix if it is available from the parameters.
*/
private void initialize() {
Parameter[] params = getParameters();
if (params != null) {
for (int i = 0; i < params.length; i++) {
if (PREFIX_KEY.equals(params[i].getName())) {
prefix = params[i].getValue();
break;
}
}
}
}
}