org.opencms.search.documents
Class CmsHighlightFinder

java.lang.Object
  org.opencms.search.documents.CmsHighlightFinder

public final class CmsHighlightFinder
extends Object

Adapted from Maik Schreiber's LuceneTools.java,v 1.5 2001/10/16 07:25:55. Alterations include: + Changed to support Lucene 1.3 release (requires no change to Lucene code base but consequently no longer supports MultiTermQuery, RangeQuery and PrefixQuery highlighting currently) + Performance enhancement - CmsHighlightExtractor caches m_query m_terms and can therefore be called repeatedly to highlight multiple results more efficently + New feature: can extract the most relevant parts of large bodies of text - with user defined size of extracts

Author:

Maik Schreiber

Constructor Summary

CmsHighlightFinder(I_CmsTermHighlighter highlighter, Query query, Analyzer analyzer)

Method Summary

String[]	getBestFragments(String text, int fragmentSize, int maxNumFragments) Highlights a text in accordance to the given m_query, extracting the most relevant sections.
String	getBestFragments(String text, int fragmentSize, int maxNumFragments, String separator) Highlights a text in accordance to the given m_query and extracting the most relevant sections.
static void	getTerms(Query query, HashSet terms, boolean prohibited) Extracts all term texts of a given Query.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CmsHighlightFinder

public CmsHighlightFinder(I_CmsTermHighlighter highlighter,
                          Query query,
                          Analyzer analyzer)
                   throws IOException

Parameters:

highlighter - I_TermHighlighter to use to highlight m_terms in the text

query - Query which contains the m_terms to be highlighted in the text

analyzer - Analyzer used to construct the Query

Throws:

IOException - if something goes wrong

Method Detail

getTerms

public static void getTerms(Query query,
                            HashSet terms,
                            boolean prohibited)
                     throws IOException

Extracts all term texts of a given Query. Term texts will be returned in lower-case.

Parameters:

query - Query to extract term texts from

terms - HashSet where extracted term texts should be put into (Elements: String)

prohibited - true to extract "prohibited" m_terms, too

Throws:

IOException - if something goes wrong

getBestFragments

public String[] getBestFragments(String text,
                                 int fragmentSize,
                                 int maxNumFragments)
                          throws IOException

Highlights a text in accordance to the given m_query, extracting the most relevant sections. The document text is analysed in fragmentSize chunks to record hit statistics across the document. After accumulating stats, the fragments with the highest scores are returned as an array of strings in order of m_score.

Parameters:

text - text to highlight m_terms in

fragmentSize - the size in bytes of each fragment to be returned

maxNumFragments - the maximum number of fragments.

Returns:

highlighted text fragments (between 0 and maxNumFragments number of fragments)

Throws:

IOException - if something goes wrong

getBestFragments

public String getBestFragments(String text,
                               int fragmentSize,
                               int maxNumFragments,
                               String separator)
                        throws IOException

Highlights a text in accordance to the given m_query and extracting the most relevant sections. The document text is analysed in fragmentSize chunks to record hit statistics across the document. After accumulating stats, the fragments with the highest scores are returned in order as "separator" delimited strings.

Parameters:

text - text to highlight m_terms in

fragmentSize - the size in bytes of each fragment to be returned

maxNumFragments - the maximum number of fragments.

separator - the separator used to intersperse the document fragments (typically " ... ")

Returns:

highlighted text

Throws:

IOException - if something goes wrong