/// <summary>
/// a constructor. A <see cref="IFragListBuilder"/> and a <see cref="IFragmentsBuilder"/> can be specified (plugins).
/// </summary>
/// <param name="phraseHighlight">true of false for phrase highlighting</param>
/// <param name="fieldMatch">true of false for field matching</param>
/// <param name="fragListBuilder">an instance of <see cref="IFragmentsBuilder"/></param>
/// <param name="fragmentsBuilder">an instance of <see cref="IFragmentsBuilder"/></param>
public FastVectorHighlighter(bool phraseHighlight, bool fieldMatch,
IFragListBuilder fragListBuilder, IFragmentsBuilder fragmentsBuilder)
{
this.phraseHighlight = phraseHighlight;
this.fieldMatch = fieldMatch;
this.fragListBuilder = fragListBuilder;
this.fragmentsBuilder = fragmentsBuilder;
}
/// <summary>
/// return the best fragment.
/// </summary>
/// <param name="fieldQuery"><see cref="FieldQuery"/> object</param>
/// <param name="reader"><see cref="IndexReader"/> of the index</param>
/// <param name="docId">document id to be highlighted</param>
/// <param name="fieldName">field of the document to be highlighted</param>
/// <param name="fragCharSize">the length (number of chars) of a fragment</param>
/// <param name="fragListBuilder"><see cref="IFragListBuilder"/> object</param>
/// <param name="fragmentsBuilder"><see cref="IFragmentsBuilder"/> object</param>
/// <param name="preTags">pre-tags to be used to highlight terms</param>
/// <param name="postTags">post-tags to be used to highlight terms</param>
/// <param name="encoder">an encoder that generates encoded text</param>
/// <returns>the best fragment (snippet) string</returns>
/// <exception cref="IOException">If there is a low-level I/O error</exception>
public string GetBestFragment(FieldQuery fieldQuery, IndexReader reader, int docId,
string fieldName, int fragCharSize,
IFragListBuilder fragListBuilder, IFragmentsBuilder fragmentsBuilder,
string[] preTags, string[] postTags, IEncoder encoder)
{
FieldFragList fieldFragList = GetFieldFragList(fragListBuilder, fieldQuery, reader, docId, fieldName, fragCharSize);
return(fragmentsBuilder.CreateFragment(reader, docId, fieldName, fieldFragList, preTags, postTags, encoder));
}
/// <summary>
/// Return the best fragments. Matches are scanned from <paramref name="matchedFields"/> and turned into fragments against
/// <paramref name="storedField"/>. The highlighting may not make sense if <paramref name="matchedFields"/> has matches with offsets that don't
/// correspond features in <paramref name="storedField"/>. It will outright throw a <see cref="IndexOutOfRangeException"/>
/// if <paramref name="matchedFields"/> produces offsets outside of <paramref name="storedField"/>. As such it is advisable that all
/// <paramref name="matchedFields"/> share the same source as <paramref name="storedField"/> or are at least a prefix of it.
/// </summary>
/// <param name="fieldQuery"><see cref="FieldQuery"/> object</param>
/// <param name="reader"><see cref="IndexReader"/> of the index</param>
/// <param name="docId">document id to be highlighted</param>
/// <param name="storedField">field of the document that stores the text</param>
/// <param name="matchedFields">fields of the document to scan for matches</param>
/// <param name="fragCharSize">the length (number of chars) of a fragment</param>
/// <param name="maxNumFragments">maximum number of fragments</param>
/// <param name="fragListBuilder"><see cref="IFragListBuilder"/> object</param>
/// <param name="fragmentsBuilder"><see cref="IFragmentsBuilder"/> object</param>
/// <param name="preTags">pre-tags to be used to highlight terms</param>
/// <param name="postTags">post-tags to be used to highlight terms</param>
/// <param name="encoder">an encoder that generates encoded text</param>
/// <returns>
/// created fragments or null when no fragments created.
/// size of the array can be less than <paramref name="maxNumFragments"/>
/// </returns>
/// <exception cref="IOException">If there is a low-level I/O error</exception>
public string[] GetBestFragments(FieldQuery fieldQuery, IndexReader reader, int docId,
string storedField, ISet <string> matchedFields, int fragCharSize, int maxNumFragments,
IFragListBuilder fragListBuilder, IFragmentsBuilder fragmentsBuilder,
string[] preTags, string[] postTags, IEncoder encoder)
{
FieldFragList fieldFragList =
GetFieldFragList(fragListBuilder, fieldQuery, reader, docId, matchedFields, fragCharSize);
return(fragmentsBuilder.CreateFragments(reader, docId, storedField, fieldFragList, maxNumFragments,
preTags, postTags, encoder));
}
