prajna.entity

Class DateTimeVerifier

java.lang.Object

prajna.entity.EntityExtractor

prajna.entity.DateTimeVerifier

All Implemented Interfaces:

EntityVerifier, RecordReasoner

public class DateTimeVerifier
extends EntityExtractor
implements EntityVerifier

Simple implementation of an EntityVerifier using a set of SimpleDateFormats. This verifier only accepts Date_Time entities, and tries to use the SimpleDateFormat objects to both extract the entities and whether they are valid. The DateTimeVerifier also uses a particular format to normalize date-time objects. By default, this is the standard W3C date-time format.

Author:

Edward Swing

Constructor Summary

Constructors

Constructor and Description
DateTimeVerifier() Create a new DateTimeVerifier, with the normalized form specified by the W3C.
DateTimeVerifier(java.lang.String normalizedForm) Create a new DateTimeVerifier using the specified format as the normalized form for date-time objects

Method Summary

Methods

Modifier and Type	Method and Description
EntityType	determineType(java.lang.String term) Determine the entity type for a particular term.
protected void	extractEntities(java.lang.String text, java.util.Map<java.lang.String,EntityTag> tokenMap) Extract date-time entities.
java.util.Map<java.lang.String,java.lang.String>	extractEntityRawTypes(java.lang.String text) Retrieve the entities and the raw types for this entity extractor.
java.lang.String	getModel() Return the model for this verifier.
java.util.Set<EntityType>	getSupportedTypes() Get the supported types for this verifier.
java.lang.String	normalize(java.lang.String term, EntityType type) Convert this term to a normalized date form.
java.util.Date	normalizeDate(java.lang.String term) Convert this term to a normalized date object.
void	setModel(java.lang.String model) Sets the model for this Verifier.
void	setNormalizedForm(java.lang.String pattern) Set the normalized form to write date-time entities.
void	setRelativeReference(java.util.Date referenceDate, RelativeDateFormat.RelativeType type) Set relative reference information for inexact parsing
void	setUseRelative(boolean flag) Set the flag indicating whether this verifier will allow relative dates.
boolean	verifyType(java.lang.String term, EntityType type) Verify if the term matches the entity type.

Methods inherited from class prajna.entity.EntityExtractor

addTagFieldMapping, addTextField, augmentRecord, extract, extract, extract, extract, getDefaultTagField, isDebug, setDebug, setDefaultTagField

Methods inherited from class java.lang.Object

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

Constructor Detail

DateTimeVerifier

public DateTimeVerifier()

Create a new DateTimeVerifier, with the normalized form specified by the W3C.

DateTimeVerifier

public DateTimeVerifier(java.lang.String normalizedForm)

Create a new DateTimeVerifier using the specified format as the normalized form for date-time objects

Parameters:

normalizedForm - the format that date-time objects are normalized into

Method Detail

determineType

public EntityType determineType(java.lang.String term)

Determine the entity type for a particular term. This method returns either EntityType.DATE_TIME or null, depending on whether the term can be parsed as a date-time object or not.

Specified by:

determineType in interface EntityVerifier

Parameters:

term - the term to check. This is the extracted entity

Returns:

the entity type for the term.

extractEntities

protected void extractEntities(java.lang.String text,
                   java.util.Map<java.lang.String,EntityTag> tokenMap)

Extract date-time entities. This method matches all internal formats against the string, and attempts to parse any date format substrings. It returns a map of those substrings, mapped to EntityType.DATE_TIME.

Specified by:

extractEntities in class EntityExtractor

Parameters:

text - the text to extract

tokenMap - the map to contain the tokens in.

extractEntityRawTypes

public java.util.Map<java.lang.String,java.lang.String> extractEntityRawTypes(java.lang.String text)

Retrieve the entities and the raw types for this entity extractor. This method runs the extraction process on the text, and generates a map that identifies each entity with a type. The DateTimeVerifier returns a map with all date-time entities mapped to "Date_Time", "Date", "Time", or "Period".

Specified by:

extractEntityRawTypes in class EntityExtractor

Parameters:

text - the text to parse for entities

Returns:

the raw entity types

getModel

public java.lang.String getModel()

Return the model for this verifier. This call returns the normalized form

Specified by:

getModel in interface EntityVerifier

Overrides:

getModel in class EntityExtractor

Returns:

the normalized form

getSupportedTypes

public java.util.Set<EntityType> getSupportedTypes()

Get the supported types for this verifier. The GeoNamesVerifier only supports EntityType.DATE_TIME types

Specified by:

getSupportedTypes in interface EntityVerifier

Returns:

a set with a single element, EntityType.DATE_TIME

normalize

public java.lang.String normalize(java.lang.String term,
                         EntityType type)

Convert this term to a normalized date form. If the term cannot be parsed, null is returned.

Specified by:

normalize in interface EntityVerifier

Parameters:

term - The term to normalize

type - the entity type, which should be EntityType.DATE_TIME

Returns:

a normalized form for the Date-time specified by the term, or null if it cannot be parsed.

normalizeDate

public java.util.Date normalizeDate(java.lang.String term)

Convert this term to a normalized date object. If the term cannot be parsed, null is returned.

Parameters:

term - The term to normalize

Returns:

a Date object for the Date-time specified by the term, or null if it cannot be parsed.

setModel

public void setModel(java.lang.String model)

Sets the model for this Verifier. This call simply sets the normalized form.

Specified by:

setModel in interface EntityVerifier

Overrides:

setModel in class EntityExtractor

Parameters:

model - the new model

setNormalizedForm

public void setNormalizedForm(java.lang.String pattern)

Set the normalized form to write date-time entities. By default, the normalized form is the form specified by the W3C.

Parameters:

pattern - the pattern for the date-time. This should conform to the SimpleDateFormat pattern

setRelativeReference

public void setRelativeReference(java.util.Date referenceDate,
                        RelativeDateFormat.RelativeType type)

Set relative reference information for inexact parsing

Parameters:

referenceDate - the reference date to use when parsing inexact terms

type - the default relation type

setUseRelative

public void setUseRelative(boolean flag)

Set the flag indicating whether this verifier will allow relative dates. By default, the flag is true, enabling relative dates. Relative dates are those specified without a year reference (e.g., March 17).

Parameters:

flag - whether to allow relative dates or not.

verifyType

public boolean verifyType(java.lang.String term,
                 EntityType type)

Verify if the term matches the entity type. If the type is EntityType.DATE_TIME, and this verifier could resolve it, then the term is valid. Otherwise, this returns false.

Specified by:

verifyType in interface EntityVerifier

Parameters:

term - the term to check

type - the entity type

Returns:

true if the type is EntityType.DATE_TIME, and the term can be parsed. False otherwise.