de.fu_berlin.ties.context
Class Representation

java.lang.Object
  extended by de.fu_berlin.ties.context.Representation
Direct Known Subclasses:
AbstractRepresentation

public abstract class Representation
extends Object

Abstract class that manages context representations for entity recognition and information extraction. Subclasses must implement the buildContext(Element, String, String, String, PriorRecognitions, Map, String) method for building representations.

Version:
$Revision: 1.13 $, $Date: 2004/11/04 15:26:51 $, $Author: siefkes $
Author:
Christian Siefkes

Constructor Summary
Representation(int recogNum)
          Creates a new instance.
 
Method Summary
 FeatureVector buildContext(Document document, PriorRecognitions priorRecognitions, Map<Element,List<LocalFeature>> featureCache, String logPurpose)
          Builds the context representation of a document.
 FeatureVector buildContext(Element element, PriorRecognitions priorRecognitions, Map<Element,List<LocalFeature>> featureCache, String logPurpose)
          Builds the context representation of an element.
abstract  FeatureVector buildContext(Element element, String leftText, String mainText, String rightText, PriorRecognitions priorRecognitions, Map<Element,List<LocalFeature>> featureCache, String logPurpose)
          Builds the context representation of text in an element.
 PriorRecognitions createRecognitionBuffer()
          Creates a buffer to be filled with prior Recognitions and passed as argument to the buildContext(Element, String, String, String, PriorRecognitions, Map, String) method.
 int getRecognitionNumber()
          Returns the number of preceding recognitions to represent.
 String toString()
          Returns a string representation of this object.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Representation

public Representation(int recogNum)
Creates a new instance.

Parameters:
recogNum - the number of preceding recognitions to represent
Method Detail

buildContext

public FeatureVector buildContext(Document document,
                                  PriorRecognitions priorRecognitions,
                                  Map<Element,List<LocalFeature>> featureCache,
                                  String logPurpose)
                           throws ClassCastException
Builds the context representation of a document. The default implementation delegates to the buildContext(Element, PriorRecognitions, Map, String) method, using the root element of the document.

Parameters:
document - the XML document whose context should be represented
priorRecognitions - a buffer of the last Recognitions from the document, created by calling createRecognitionBuffer(); might be null
featureCache - a cache of (local) feature, should be re-used between all calls for the nodes in a single document (but must not be re-used when building the context of nodes in different documents!)
logPurpose - the type of contexts of main interest to the caller (e.g. "Token" or "Sentence"), used for logging
Returns:
a vector of features considered relevant for representation
Throws:
ClassCastException - if the priorRecognitions buffer contains objects that aren't Recognitions

buildContext

public FeatureVector buildContext(Element element,
                                  PriorRecognitions priorRecognitions,
                                  Map<Element,List<LocalFeature>> featureCache,
                                  String logPurpose)
                           throws ClassCastException
Builds the context representation of an element. The default implementation delegates to the buildContext(Element, String, String, String, PriorRecognitions, Map, String) method, using the full textual content of the element as mainText and empty strings as leftText and rightText.

Parameters:
element - the element whose context should be represented
priorRecognitions - a buffer of the last Recognitions from the document, created by calling createRecognitionBuffer(); might be null
featureCache - a cache of (local) feature, should be re-used between all calls for the nodes in a single document (but must not be re-used when building the context of nodes in different documents!)
logPurpose - the type of contexts of main interest to the caller (e.g. "Token" or "Sentence"), used for logging
Returns:
a vector of features considered relevant for representation
Throws:
ClassCastException - if the priorRecognitions buffer contains objects that aren't Recognitions

buildContext

public abstract FeatureVector buildContext(Element element,
                                           String leftText,
                                           String mainText,
                                           String rightText,
                                           PriorRecognitions priorRecognitions,
                                           Map<Element,List<LocalFeature>> featureCache,
                                           String logPurpose)
                                    throws ClassCastException
Builds the context representation of text in an element. Returns a feature vector of all context features considered relevant for representation.

Parameters:
element - the element whose context should be represented
leftText - textual content to the left of (preceding) mainText, might be empty
mainText - the main textual content to represent, might be empty
rightText - textual content to the right of (following) mainText, might be empty
priorRecognitions - a buffer of the last Recognitions from the document, created by calling createRecognitionBuffer(); might be null
featureCache - a cache of (local) feature, should be re-used between all calls for the nodes in a single document (but must not be re-used when building the context of nodes in different documents!)
logPurpose - the type of contexts of main interest to the caller (e.g. "Token" or "Sentence"), used for logging
Returns:
a vector of features considered relevant for representation
Throws:
ClassCastException - if the priorRecognitions buffer contains objects that aren't Recognitions

createRecognitionBuffer

public PriorRecognitions createRecognitionBuffer()
Creates a buffer to be filled with prior Recognitions and passed as argument to the buildContext(Element, String, String, String, PriorRecognitions, Map, String) method. The caller must PriorRecognitions.add(Recognition)new recognitions to the buffer but it is not necessary to remove them -- the buffer will automatically delete the oldest recognitions when appropriate.

Returns:
a buffer to be used for collecting prior Recognitions

getRecognitionNumber

public int getRecognitionNumber()
Returns the number of preceding recognitions to represent.

Returns:
the value of the attibute

toString

public String toString()
Returns a string representation of this object.

Overrides:
toString in class Object
Returns:
a textual representation


Copyright © 2003-2004 Christian Siefkes. All Rights Reserved.