net.sf.classifier4J
Interface IClassifier

All Known Subinterfaces:

ICategorisedClassifier, ITrainableClassifier

All Known Implementing Classes:

AbstractCategorizedTrainableClassifier, AbstractClassifier, SimpleClassifier

public interface IClassifier

Defines an interface for the classification of Strings.

Use the isMatch method if you want true/false matching, or use the classify method if you match probability.

The isMatch method will return a boolean representing if a string matches whatever criteria the implmentation is matching on. In the default implemnetation this is done by calling classify and checking if the returned match probability is greater than or equal to DEFAULT_CUTOFF.

The classify method will return a double value representing the likelyhood that the string passed to it is a match on whatever criteria the implmentation is matching on.

When implementing this class, it is recommended that the classify method should not return the values 1 or 0 except in the cases there the classifier can guarentee that the string is a match doe does not match. For non-absolute matching algorithms LOWER_BOUND and UPPER_BOUND should be used.

Author:

Nick Lothian, Peter Leschev

See Also:

AbstractClassifier

Field Summary

static double	DEFAULT_CUTOFF Default cutoff value used by defautl implmentation of isMatch.
static double	LOWER_BOUND The minimum likelyhood that a string matches
static double	NEUTRAL_PROBABILITY Default value to use if the implementation cannot work out how well a string matches.
static double	UPPER_BOUND The maximum likelyhood that a string matches

Method Summary

double	classify(java.lang.String input) Function to determine the probability string matches a criteria.
boolean	isMatch(double matchProbability) Convenience method which takes a match probability (calculated by classify(java.lang.String)) and checks if it would be classified as a match or not
boolean	isMatch(java.lang.String input) Function to determine if a string matches a criteria.
void	setMatchCutoff(double cutoff) Sets the cutoff below which the input is not considered a match

Field Detail

NEUTRAL_PROBABILITY

public static final double NEUTRAL_PROBABILITY

Default value to use if the implementation cannot work out how well a string matches.

See Also:

Constant Field Values

LOWER_BOUND

public static final double LOWER_BOUND

The minimum likelyhood that a string matches

See Also:

Constant Field Values

UPPER_BOUND

public static final double UPPER_BOUND

The maximum likelyhood that a string matches

See Also:

Constant Field Values

DEFAULT_CUTOFF

public static final double DEFAULT_CUTOFF

Default cutoff value used by defautl implmentation of isMatch. Any match probability greater than or equal to this value will be classified as a match. The value is 0.9d

See Also:

Constant Field Values

Method Detail

setMatchCutoff

public void setMatchCutoff(double cutoff)

Sets the cutoff below which the input is not considered a match

Parameters:

cutoff - the level below which isMatch will return false. Should be between 0 and 1.

classify

public double classify(java.lang.String input)
                throws ClassifierException

Function to determine the probability string matches a criteria.

Parameters:

input - the string to classify

Returns:

the likelyhood that this string is a match for this net.sf.classifier4J. 1 means 100% likely.

Throws:

ClassifierException - If a non-recoverable problem occurs

isMatch

public boolean isMatch(java.lang.String input)
                throws ClassifierException

Function to determine if a string matches a criteria.

Parameters:

input - the string to classify

Returns:

true if the input string has a probability >= the cutoff probability of matching

Throws:

ClassifierException - If a non-recoverable problem occurs

isMatch

public boolean isMatch(double matchProbability)

Convenience method which takes a match probability (calculated by classify(java.lang.String)) and checks if it would be classified as a match or not

Parameters:

matchProbability -

Returns:

true if match, false otherwise