| /* |
| * 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.lucene.analysis.miscellaneous; |
| |
| import org.apache.lucene.analysis.TokenFilter; |
| import org.apache.lucene.analysis.TokenStream; |
| import org.apache.lucene.analysis.tokenattributes.CharTermAttribute; |
| |
| import java.io.IOException; |
| |
| /** |
| * Trims leading and trailing whitespace from Tokens in the stream. |
| */ |
| public final class TrimFilter extends TokenFilter { |
| |
| private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class); |
| |
| /** |
| * Create a new {@link TrimFilter}. |
| * @param in the stream to consume |
| */ |
| public TrimFilter(TokenStream in) { |
| super(in); |
| } |
| |
| @Override |
| public boolean incrementToken() throws IOException { |
| if (!input.incrementToken()) return false; |
| |
| char[] termBuffer = termAtt.buffer(); |
| int len = termAtt.length(); |
| //TODO: Is this the right behavior or should we return false? Currently, " ", returns true, so I think this should |
| //also return true |
| if (len == 0){ |
| return true; |
| } |
| int start = 0; |
| int end = 0; |
| |
| // eat the first characters |
| for (start = 0; start < len && Character.isWhitespace(termBuffer[start]); start++) { |
| } |
| // eat the end characters |
| for (end = len; end >= start && Character.isWhitespace(termBuffer[end - 1]); end--) { |
| } |
| if (start > 0 || end < len) { |
| if (start < end) { |
| termAtt.copyBuffer(termBuffer, start, (end - start)); |
| } else { |
| termAtt.setEmpty(); |
| } |
| } |
| |
| return true; |
| } |
| } |