org.terrier.querying
Class Decorate

java.lang.Object
  org.terrier.querying.Decorate

All Implemented Interfaces:

PostFilter, PostProcess, Process

public class Decorate
extends java.lang.Object
implements PostProcess, PostFilter

This class decorates a result set with metadata. This metadata can be highlighted, can have a query biased summary created, and also be escaped for display in another format. Controls: <ul>

summaries - comma or semicolon delimited list of the key names for which a query biased summary should be created. e.g. summaries:snippet

emphasis - comma or semicolon delimited list of they key names that should have boldened for occurrences of the query terms. e.g. emphasis:title;snippet

earlyDecorate - comma or semicolon delimited list of the key names that should be decorated early, e.g. to support another PostProcess using them.

escape - comma or semicolon delimited list of the key names that should be escaped e.g. escape:title;snippet;url

. Currently, per-key type escaping is not supported. The default escape type is defined using the property decorate.escape. </li> Properties:

• decorate.escape - default escape type for metadata. Default is html. See StringTools.ESCAPE for more information.

Since:

3.0

Author:

Craig Macdonald, Vassilis Plachouras, Ben He

Field Summary

protected static java.lang.String[]	CONTROL_VALUE_DELIMS delimiters for breaking down the values of controls further
protected static java.util.regex.Pattern	controlNonVisibleCharacters
protected java.util.regex.Matcher	controlNonVisibleCharactersMatcher
protected static StringTools.ESCAPE	defaultEscape what is the default escape sequence
protected java.util.regex.Pattern	highlight highlighting pattern for the current query
protected LRUMap<java.lang.Integer,java.lang.String[]>	metaCache The cache used for the meta data.
protected MetaIndex	metaIndex The meta index server.
protected java.lang.String[]	qTerms query terms of the current query

Fields inherited from interface org.terrier.querying.PostFilter

FILTER_ADJUSTED, FILTER_OK, FILTER_REMOVE

Constructor Summary

Decorate()

Method Summary

protected boolean	checkControl(java.lang.String control_name, SearchRequest srq)
byte	filter(Manager m, SearchRequest q, ResultSet rs, int rank, int docid) Called for each result in the resultset, used to filter out unwanted results.
protected java.util.regex.Pattern	generateEmphasisPattern(java.lang.String[] _qTerms) Creates a regular expression pattern to highlight query terms metadata.
protected java.lang.String	generateQueryBiasedSummary(java.lang.String extract, java.lang.String[] _qTerms)
java.lang.String	getInfo() Returns the name of the post processor.
protected java.lang.String[]	getMetadata(java.lang.String[] metaKeys, int docid)
protected java.lang.String[][]	getMetadata(java.lang.String[] metaKeys, int[] docids)
void	new_query(Manager m, SearchRequest q, ResultSet rs) Called before the processing of a resultset using this PostFilter is applied.
void	process(Manager manager, SearchRequest q) decoration at the postprocess stage.

Methods inherited from class java.lang.Object

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

Field Detail

CONTROL_VALUE_DELIMS

protected static final java.lang.String[] CONTROL_VALUE_DELIMS

delimiters for breaking down the values of controls further

metaCache

protected LRUMap<java.lang.Integer,java.lang.String[]> metaCache

The cache used for the meta data. Implements a Least-Recently-Used policy for retaining the most recently accessed metadata.

metaIndex

protected MetaIndex metaIndex

The meta index server. It is provided by the manager.

controlNonVisibleCharacters

protected static final java.util.regex.Pattern controlNonVisibleCharacters

defaultEscape

protected static final StringTools.ESCAPE defaultEscape

what is the default escape sequence

controlNonVisibleCharactersMatcher

protected java.util.regex.Matcher controlNonVisibleCharactersMatcher

highlight

protected java.util.regex.Pattern highlight

highlighting pattern for the current query

qTerms

protected java.lang.String[] qTerms

query terms of the current query

Constructor Detail

Decorate

public Decorate()

Method Detail

new_query

public void new_query(Manager m,
                      SearchRequest q,
                      ResultSet rs)

Called before the processing of a resultset using this PostFilter is applied. Can be used to save information for the duration of the query.

Specified by:

new_query in interface PostFilter

Parameters:

m - The manager controlling this query

q - The search request being processed

rs - the resultset that is being iterated through

filter

public byte filter(Manager m,
                   SearchRequest q,
                   ResultSet rs,
                   int rank,
                   int docid)

Called for each result in the resultset, used to filter out unwanted results.

Specified by:

filter in interface PostFilter

Parameters:

m - The manager controlling this query

q - The search request being processed

rank - which array index in the resultset have we reached

docid - The document number of the currently being procesed result.

process

public void process(Manager manager,
                    SearchRequest q)

decoration at the postprocess stage. only decorate if required for future postfilter or postprocesses.

Specified by:

process in interface Process

Parameters:

manager - The manager instance handling this search session.

q - the current query being processed

getMetadata

protected java.lang.String[] getMetadata(java.lang.String[] metaKeys,
                                         int docid)

getMetadata

protected java.lang.String[][] getMetadata(java.lang.String[] metaKeys,
                                           int[] docids)

generateQueryBiasedSummary

protected java.lang.String generateQueryBiasedSummary(java.lang.String extract,
                                                      java.lang.String[] _qTerms)

generateEmphasisPattern

protected java.util.regex.Pattern generateEmphasisPattern(java.lang.String[] _qTerms)

Creates a regular expression pattern to highlight query terms metadata.

Parameters:

_qTerms - query terms

Returns:

Pattern to apply

checkControl

protected boolean checkControl(java.lang.String control_name,
                               SearchRequest srq)

getInfo

public java.lang.String getInfo()

Returns the name of the post processor.

Specified by:

getInfo in interface Process

Returns:

String the name of the post processor.