org.geotools.filter.function
Class ClassificationFunction

java.lang.Object
  org.geotools.filter.expression.ExpressionAbstract
      org.geotools.filter.DefaultExpression
          org.geotools.filter.FunctionExpressionImpl
              org.geotools.filter.function.ClassificationFunction

All Implemented Interfaces:

org.opengis.filter.expression.Expression, Expression, ExpressionType, Factory, org.opengis.filter.expression.Function, FunctionExpression

Direct Known Subclasses:

CustomClassifierFunction, ExplicitClassificationFunction, RangedClassificationFunction

public abstract class ClassificationFunction

extends FunctionExpressionImpl

implements FunctionExpression

Parent for classifiers which break a feature collection into the specified number of classes.

Author:

James Macgill, Cory Horner, Refractions Research Inc.

Field Summary

Fields inherited from class org.geotools.filter.DefaultExpression

expressionType, permissiveConstruction

Fields inherited from interface org.geotools.filter.expression.ExpressionType

ATTRIBUTE, ATTRIBUTE_DOUBLE, ATTRIBUTE_GEOMETRY, ATTRIBUTE_INTEGER, ATTRIBUTE_STRING, ATTRIBUTE_UNDECLARED, FUNCTION, LITERAL_DOUBLE, LITERAL_GEOMETRY, LITERAL_INTEGER, LITERAL_STRING, MATH_ADD, MATH_DIVIDE, MATH_MULTIPLY, MATH_SUBTRACT

Constructor Summary

ClassificationFunction()
Creates a new instance of ClassificationFunction

Method Summary

protected int	decimalPlaces(double slotWidth) Determines the number of decimal places to truncate the interval at (public for testing purposes only).
abstract java.lang.Object	evaluate(Feature feature) Evaluates the expression against an instance of Feature.
protected double	fixRound(double value, int decimalPlaces, boolean up) Corrects a round off operation by incrementing or decrementing the decimal place (preferably the smallest one).
int	getArgCount() Returns the number of arguments this requires.
Expression[]	getArgs() Gets the arguments to be evaluated by this function.
FeatureCollection	getCollection()
Expression	getExpression()
abstract java.lang.String	getName() Gets the name of this function.
int	getNumberOfClasses()
ProgressListener	getProgressListener()
java.lang.Object	getValue(int index)
protected double	round(double value, int decimalPlaces) Truncates a double to a certain number of decimals places.
void	setArgs(Expression[] args) Sets the arguments to be evaluated by this function.
void	setCollection(FeatureCollection fc)
void	setExpression(Expression e)
void	setNumberOfClasses(int i)
void	setProgressListener(ProgressListener progress)

Methods inherited from class org.geotools.filter.FunctionExpressionImpl

accept, getImplementationHints, getParameters, getType, setName, setParameters

Methods inherited from class org.geotools.filter.DefaultExpression

accept, evaluate, getValue, isAttributeExpression, isExpression, isGeometryExpression, isLiteralExpression, isMathExpression, isMathExpression

Methods inherited from class org.geotools.filter.expression.ExpressionAbstract

eval

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.geotools.filter.expression.FunctionExpression

getType

Methods inherited from interface org.geotools.filter.expression.Expression

accept, getValue

Methods inherited from interface org.opengis.filter.expression.Expression

accept, evaluate

Methods inherited from interface org.geotools.factory.Factory

getImplementationHints

Methods inherited from interface org.opengis.filter.expression.Function

getParameters, setName, setParameters

Constructor Detail

ClassificationFunction

public ClassificationFunction()

Creates a new instance of ClassificationFunction

Method Detail

getArgCount

public int getArgCount()

Description copied from interface: FunctionExpression

Returns the number of arguments this requires. For example [arg1][arg2]. This function must have EXACTLY 2 arguments, so this function would return 2. The parser might use this information to ensure validity, and its also for reporting capabilities. NOTE: this was previously javadoc-ed incorrectly, please note the new definition. NOTE: you cannot have a function with a variable number of arguments.

Specified by:

getArgCount in interface FunctionExpression

Specified by:

getArgCount in class FunctionExpressionImpl

Returns:

the number of args.

getNumberOfClasses

public int getNumberOfClasses()

setNumberOfClasses

public void setNumberOfClasses(int i)

getCollection

public FeatureCollection getCollection()

setCollection

public void setCollection(FeatureCollection fc)

getExpression

public Expression getExpression()

setExpression

public void setExpression(Expression e)

getProgressListener

public ProgressListener getProgressListener()

setProgressListener

public void setProgressListener(ProgressListener progress)

getArgs

public Expression[] getArgs()

Description copied from interface: FunctionExpression

Gets the arguments to be evaluated by this function.

Specified by:

getArgs in interface FunctionExpression

Overrides:

getArgs in class FunctionExpressionImpl

getName

public abstract java.lang.String getName()

Description copied from interface: FunctionExpression

Gets the name of this function.

Specified by:

getName in interface FunctionExpression

Overrides:

getName in class FunctionExpressionImpl

Returns:

the name of the function.

setArgs

public void setArgs(Expression[] args)

Description copied from interface: FunctionExpression

Sets the arguments to be evaluated by this function.

Specified by:

setArgs in interface FunctionExpression

Overrides:

setArgs in class FunctionExpressionImpl

evaluate

public abstract java.lang.Object evaluate(Feature feature)

Description copied from interface: Expression

Evaluates the expression against an instance of Feature.

Specified by:

evaluate in interface Expression

Overrides:

evaluate in class DefaultExpression

Parameters:

feature - Specified feature to use when returning value.

Returns:

The value of this expression based on the feature.

getValue

public java.lang.Object getValue(int index)

decimalPlaces

protected int decimalPlaces(double slotWidth)

Determines the number of decimal places to truncate the interval at (public for testing purposes only).

Parameters:

slotWidth -

Returns:

round

protected double round(double value,
                       int decimalPlaces)

Truncates a double to a certain number of decimals places. Note: truncation at zero decimal places will still show up as x.0, since we're using the double type.

Parameters:

value - number to round-off

decimalPlaces - number of decimal places to leave

Returns:

the rounded value

fixRound

protected double fixRound(double value,
                          int decimalPlaces,
                          boolean up)

Corrects a round off operation by incrementing or decrementing the decimal place (preferably the smallest one). This should usually be used to adjust the bounds to include a value. Example: 0.31-->0.44 where 0.44 is the maximum value and end of the range. We could just make the , round(0.31, 1)=0.3; round(0.44 max value = 0.49

Parameters:

value -

decimalPlaces -

up -

Returns: