Package org.apache.jackrabbit.core.query.lucene

Class DefaultHighlighter

java.lang.Object

org.apache.jackrabbit.core.query.lucene.DefaultHighlighter

Direct Known Subclasses:

WeightedHighlighter

public class DefaultHighlighter
extends Object

This is an adapted version of the FulltextHighlighter posted in issue: LUCENE-644.

Important: for this highlighter to function properly, field must be stored with token offsets.
Use Field constructor Field(String, String, Field.Store, Field.Index, Field.TermVector) where the last argument is either Field.TermVector.WITH_POSITIONS_OFFSETS or Field.TermVector.WITH_OFFSETS

See Also:

TermPositionVector, TermFreqVector

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAXFRAGMENTS	A default value of 3
static int	DEFAULT_SURROUND	A default value of 75
static String	END_EXCERPT
static String	END_FRAGMENT_SEPARATOR
static String	END_HIGHLIGHT
static String	START_EXCERPT
static String	START_FRAGMENT_SEPARATOR
static String	START_HIGHLIGHT

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DefaultHighlighter()

Method Summary

Modifier and Type	Method	Description
protected String	createDefaultExcerpt(String text, String excerptStart, String excerptEnd, String fragmentStart, String fragmentEnd, int maxLength)	Creates a default excerpt with the given text.
protected String	doHighlight(TermPositionVector tvec, Set<Term[]> queryTerms, String text, String excerptStart, String excerptEnd, String fragmentStart, String fragmentEnd, String hlStart, String hlEnd, int maxFragments, int surround)
protected String	escape(String input)	Escapes input text suitable for the output format.
static String	highlight(TermPositionVector tvec, Set<Term[]> queryTerms, String text, int maxFragments, int surround)
static String	highlight(TermPositionVector tvec, Set<Term[]> queryTerms, String text, String excerptStart, String excerptEnd, String fragmentStart, String fragmentEnd, String hlStart, String hlEnd, int maxFragments, int surround)
protected String	mergeFragments(TermVectorOffsetInfo[] offsets, String text, String excerptStart, String excerptEnd, String fragmentStart, String fragmentEnd, String hlStart, String hlEnd, int maxFragments, int surround)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAXFRAGMENTS

public static final int DEFAULT_MAXFRAGMENTS

A default value of 3

See Also:

Constant Field Values

DEFAULT_SURROUND

public static final int DEFAULT_SURROUND

A default value of 75

See Also:

Constant Field Values

START_EXCERPT

public static final String START_EXCERPT

See Also:

Constant Field Values

END_EXCERPT

public static final String END_EXCERPT

See Also:

Constant Field Values

START_FRAGMENT_SEPARATOR

public static final String START_FRAGMENT_SEPARATOR

See Also:

Constant Field Values

END_FRAGMENT_SEPARATOR

public static final String END_FRAGMENT_SEPARATOR

See Also:

Constant Field Values

START_HIGHLIGHT

public static final String START_HIGHLIGHT

See Also:

Constant Field Values

END_HIGHLIGHT

public static final String END_HIGHLIGHT

See Also:

Constant Field Values

Constructor Detail

DefaultHighlighter

protected DefaultHighlighter()

Method Detail

highlight

public static String highlight(TermPositionVector tvec,
                               Set<Term[]> queryTerms,
                               String text,
                               String excerptStart,
                               String excerptEnd,
                               String fragmentStart,
                               String fragmentEnd,
                               String hlStart,
                               String hlEnd,
                               int maxFragments,
                               int surround)
                        throws IOException

Parameters:

tvec - the term position vector for this hit

queryTerms - the query terms.

text - the original text that was used to create the tokens.

excerptStart - this string is prepended to the excerpt

excerptEnd - this string is appended to the excerpt

fragmentStart - this string is prepended to every fragment

fragmentEnd - this string is appended to the end of every fragement.

hlStart - the string used to prepend a highlighted token, for example "<b>"

hlEnd - the string used to append a highlighted token, for example "</b>"

maxFragments - the maximum number of fragments

surround - the maximum number of chars surrounding a highlighted token

Returns:

a String with text fragments where tokens from the query are highlighted

Throws:

IOException

highlight

public static String highlight(TermPositionVector tvec,
                               Set<Term[]> queryTerms,
                               String text,
                               int maxFragments,
                               int surround)
                        throws IOException

Parameters:

tvec - the term position vector for this hit

queryTerms - the query terms.

text - the original text that was used to create the tokens.

maxFragments - the maximum number of fragments

surround - the maximum number of chars surrounding a highlighted token

Returns:

a String with text fragments where tokens from the query are highlighted

Throws:

IOException

doHighlight

protected String doHighlight(TermPositionVector tvec,
                             Set<Term[]> queryTerms,
                             String text,
                             String excerptStart,
                             String excerptEnd,
                             String fragmentStart,
                             String fragmentEnd,
                             String hlStart,
                             String hlEnd,
                             int maxFragments,
                             int surround)
                      throws IOException

Throws:

IOException

See Also:

highlight(TermPositionVector, Set, String, String, String, String, String, String, String, int, int)

mergeFragments

protected String mergeFragments(TermVectorOffsetInfo[] offsets,
                                String text,
                                String excerptStart,
                                String excerptEnd,
                                String fragmentStart,
                                String fragmentEnd,
                                String hlStart,
                                String hlEnd,
                                int maxFragments,
                                int surround)
                         throws IOException

Throws:

IOException

createDefaultExcerpt

protected String createDefaultExcerpt(String text,
                                      String excerptStart,
                                      String excerptEnd,
                                      String fragmentStart,
                                      String fragmentEnd,
                                      int maxLength)
                               throws IOException

Creates a default excerpt with the given text.

Parameters:

text - the text.

excerptStart - the excerpt start.

excerptEnd - the excerpt end.

fragmentStart - the fragment start.

fragmentEnd - the fragment end.

maxLength - the maximum length of the fragment.

Returns:

a default excerpt.

Throws:

IOException - if an error occurs while reading from the text.

escape

protected String escape(String input)

Escapes input text suitable for the output format.

By default does XML-escaping. Can be overridden for other formats.

Parameters:

input - raw text.

Returns:

text suitably escaped.