content: package org.apache.lucene.search.vectorhighlight;
  
  /**
   * 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.
   */
  
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Set;
  
  public class SimpleBoundaryScanner implements BoundaryScanner {
    
    public static final int DEFAULT_MAX_SCAN = 20;
    public static final Character[] DEFAULT_BOUNDARY_CHARS = {'.', ',', '!', '?', ' ', '\t', '\n'};
  
    protected int maxScan;
    protected Set<Character> boundaryChars;
    
    public SimpleBoundaryScanner(){
      this( DEFAULT_MAX_SCAN, DEFAULT_BOUNDARY_CHARS );
    }
    
    public SimpleBoundaryScanner( int maxScan ){
      this( maxScan, DEFAULT_BOUNDARY_CHARS );
    }
    
    public SimpleBoundaryScanner( Character[] boundaryChars ){
      this( DEFAULT_MAX_SCAN, boundaryChars );
    }
    
    public SimpleBoundaryScanner( int maxScan, Character[] boundaryChars ){
      this.maxScan = maxScan;
      this.boundaryChars = new HashSet<Character>();
      this.boundaryChars.addAll(Arrays.asList(boundaryChars));
    }
    
    public SimpleBoundaryScanner( int maxScan, Set<Character> boundaryChars ){
      this.maxScan = maxScan;
      this.boundaryChars = boundaryChars;
    }
  
    public int findStartOffset(StringBuilder buffer, int start) {
      // avoid illegal start offset
      if( start > buffer.length() || start < 1 ) return start;
      int offset, count = maxScan;
      for( offset = start; offset > 0 && count > 0; count-- ){
        // found?
        if( boundaryChars.contains( buffer.charAt( offset - 1 ) ) ) return offset;
        offset--;
      }
      // not found
      return start;
    }
  
    public int findEndOffset(StringBuilder buffer, int start) {
      // avoid illegal start offset
      if( start > buffer.length() || start < 0 ) return start;
      int offset, count = maxScan;
      //for( offset = start; offset <= buffer.length() && count > 0; count-- ){
      for( offset = start; offset < buffer.length() && count > 0; count-- ){
        // found?
        if( boundaryChars.contains( buffer.charAt( offset ) ) ) return offset;
        offset++;
      }
      // not found
      return start;
    }
  }
  