info.ephyra.patternlearning
Class PatternExtractor

java.lang.Object
  info.ephyra.patternlearning.PatternExtractor

public class PatternExtractor
extends java.lang.Object

Extracts answer patterns from text passages and adds them to the AnswerPatternFilter.

Version:

2006-04-04

Author:

Nico Schlaefer

Field Summary

private static int

MAX_TAGS Maximum number of NE and CONTEXT tags in a pattern (for time performance).

Constructor Summary

PatternExtractor()

Method Summary

static void	extract(Result result, java.lang.String as) Extracts answer patterns from the answer string of a Result object and adds them to the AnswerPatternFilter.
private static java.lang.String[]	extractPatterns(java.lang.String sentence) Extract basic answer patterns from the sentence.
private static java.lang.String[]	generalizePatterns(java.lang.String[] patterns, java.lang.String prop) Generates more generic patterns from the initial patterns.
private static java.lang.String	prepSentence(java.lang.String sentence, java.lang.String to, java.lang.String[] cos, java.lang.String po, java.lang.String[][] nes) Prepares a sentence for pattern extraction.
private static java.lang.String	replaceContext(java.lang.String sentence, java.lang.String[] cos, java.lang.String[][] nes) Replaces all CONTEXT objects in the sentence.
private static java.lang.String	replaceNes(java.lang.String sentence, java.lang.String[][] nes) Replaces all NEs in the sentence.
private static java.lang.String	replaceProperty(java.lang.String sentence, java.lang.String as, java.lang.String[][] nes) Replaces all PROPERTY objects in the sentence.
private static java.lang.String	replaceTarget(java.lang.String sentence, java.lang.String to, java.lang.String[][] nes) Replaces all TARGET objects in the sentence.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_TAGS

private static final int MAX_TAGS

Maximum number of NE and CONTEXT tags in a pattern (for time performance).

See Also:

Constant Field Values

Constructor Detail

PatternExtractor

public PatternExtractor()

Method Detail

replaceTarget

private static java.lang.String replaceTarget(java.lang.String sentence,
                                              java.lang.String to,
                                              java.lang.String[][] nes)

Replaces all TARGET objects in the sentence.

Parameters:

sentence - input sentence

to - the TARGET object of the question

nes - the NEs in the sentence

Returns:

sentence with TARGET tags or null, if the sentence does not contain the TARGET

replaceProperty

private static java.lang.String replaceProperty(java.lang.String sentence,
                                                java.lang.String as,
                                                java.lang.String[][] nes)

Replaces all PROPERTY objects in the sentence.

Parameters:

sentence - input sentence

as - the answer to the question

nes - the NEs in the sentence

Returns:

sentence with PROPERTY tags or null, if the sentence does not contain the answer

replaceContext

private static java.lang.String replaceContext(java.lang.String sentence,
                                               java.lang.String[] cos,
                                               java.lang.String[][] nes)

Replaces all CONTEXT objects in the sentence.

Parameters:

sentence - input sentence

cos - the CONTEXT objects of the question

nes - the NEs in the sentence

Returns:

sentence with CONTEXT tags

replaceNes

private static java.lang.String replaceNes(java.lang.String sentence,
                                           java.lang.String[][] nes)

Replaces all NEs in the sentence.

Parameters:

sentence - input sentence

nes - the NEs in the sentence

Returns:

sentence with NE tags

prepSentence

private static java.lang.String prepSentence(java.lang.String sentence,
                                             java.lang.String to,
                                             java.lang.String[] cos,
                                             java.lang.String po,
                                             java.lang.String[][] nes)

Prepares a sentence for pattern extraction.

Parameters:

sentence - input sentence

to - the TARGET object of the question

cos - the CONTEXT objects of the question

po - the answer to the question

nes - the NEs in the sentence

Returns:

sentence ready for pattern extraction or null, if there is no TARGET or PROPERTY object in the input sentence

extractPatterns

private static java.lang.String[] extractPatterns(java.lang.String sentence)

Extract basic answer patterns from the sentence.

Parameters:

sentence - input sentence

Returns:

basic answer patterns

generalizePatterns

private static java.lang.String[] generalizePatterns(java.lang.String[] patterns,
                                                     java.lang.String prop)

Generates more generic patterns from the initial patterns.

Parameters:

patterns - initial patterns

prop - PROPERTY that the patterns extract

Returns:

more generic patterns

extract

public static void extract(Result result,
                           java.lang.String as)

Extracts answer patterns from the answer string of a Result object and adds them to the AnswerPatternFilter.

Parameters:

result - Result object

as - the answer to the question