content: /**
   * 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.solr.analysis;
  
  import org.apache.lucene.analysis.TokenFilter;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
  
  import java.io.IOException;
  
  /**
   * Trims leading and trailing whitespace from Tokens in the stream.
   *
   * @version $Id:$
   */
  public final class TrimFilter extends TokenFilter {
  
    final boolean updateOffsets;
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
  
  
    public TrimFilter(TokenStream in, boolean updateOffsets) {
      super(in);
      this.updateOffsets = updateOffsets;
    }
  
    @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;
      int endOff = 0;
  
      // eat the first characters
      //QUESTION: Should we use Character.isWhitespace() instead?
      for (start = 0; start < len && termBuffer[start] <= ' '; start++) {
      }
      // eat the end characters
      for (end = len; end >= start && termBuffer[end - 1] <= ' '; end--) {
        endOff++;
      }
      if (start > 0 || end < len) {
        if (start < end) {
          termAtt.copyBuffer(termBuffer, start, (end - start));
        } else {
          termAtt.setEmpty();
        }
        if (updateOffsets) {
          int newStart = offsetAtt.startOffset()+start;
          int newEnd = offsetAtt.endOffset() - (start<end ? endOff:0);
          offsetAtt.setOffset(newStart, newEnd);
        }
      }
  
      return true;
    }
  }
  