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.io.IOException;
  
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.search.highlight.Encoder;
  
  /**
   * {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder} is an interface for fragments (snippets) builder classes.
   * A {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder} class can be plugged in to
   * {@link org.apache.lucene.search.vectorhighlight.FastVectorHighlighter}.
   */
  public interface FragmentsBuilder {
  
    /**
     * create a fragment.
     * 
     * @param reader IndexReader of the index
     * @param docId document id to be highlighted
     * @param fieldName field of the document to be highlighted
     * @param fieldFragList FieldFragList object
     * @return a created fragment or null when no fragment created
     * @throws IOException
     */
    public String createFragment( IndexReader reader, int docId, String fieldName,
        FieldFragList fieldFragList ) throws IOException;
  
    /**
     * create multiple fragments.
     * 
     * @param reader IndexReader of the index
     * @param docId document id to be highlighter
     * @param fieldName field of the document to be highlighted
     * @param fieldFragList FieldFragList object
     * @param maxNumFragments maximum number of fragments
     * @return created fragments or null when no fragments created.
     *         size of the array can be less than maxNumFragments
     * @throws IOException
     */
    public String[] createFragments( IndexReader reader, int docId, String fieldName,
        FieldFragList fieldFragList, int maxNumFragments ) throws IOException;
  
    /**
     * create a fragment.
     * 
     * @param reader IndexReader of the index
     * @param docId document id to be highlighted
     * @param fieldName field of the document to be highlighted
     * @param fieldFragList FieldFragList object
     * @param preTags pre-tags to be used to highlight terms
     * @param postTags post-tags to be used to highlight terms
     * @param encoder an encoder that generates encoded text
     * @return a created fragment or null when no fragment created
     * @throws IOException
     */
    public String createFragment( IndexReader reader, int docId, String fieldName,
        FieldFragList fieldFragList, String[] preTags, String[] postTags,
        Encoder encoder ) throws IOException;
  
    /**
     * create multiple fragments.
     * 
     * @param reader IndexReader of the index
     * @param docId document id to be highlighter
     * @param fieldName field of the document to be highlighted
     * @param fieldFragList FieldFragList object
     * @param maxNumFragments maximum number of fragments
     * @param preTags pre-tags to be used to highlight terms
     * @param postTags post-tags to be used to highlight terms
     * @param encoder an encoder that generates encoded text
     * @return created fragments or null when no fragments created.
     *         size of the array can be less than maxNumFragments
     * @throws IOException
     */
    public String[] createFragments( IndexReader reader, int docId, String fieldName,
        FieldFragList fieldFragList, int maxNumFragments, String[] preTags, String[] postTags,
        Encoder encoder ) throws IOException;
  }
  