/*
* 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;
/**
* Like the Unix uniq(1) command, only returns tokens that are
* different from their ancestor token.
*
* <p>This filter is probably most useful if used together with a
* sortfilter.</p>
*
* @since Ant 1.8.0
*/
public class UniqFilter extends TokenFilter.ChainableReaderFilter {
private String lastLine = null;
public String filter(String string) {
if (lastLine == null || !lastLine.equals(string)) {
lastLine = string;
return lastLine;
}
return null;
}
}