org.geotools.filter.function
Class Collection_MaxFunction

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

All Implemented Interfaces:

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

public class Collection_MaxFunction

extends FunctionExpressionImpl

implements FunctionExpression

Calculates the maximum value of an attribute for a given FeatureCollection and Expression.

Since:

2.2M2

Author:

Cory Horner

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

Collection_MaxFunction()
Creates a new instance of Collection_MaxFunction

Method Summary

static CalcResult	calculateMax(FeatureCollection collection, Expression expression) Calculate maximum (using FeatureCalc) - only one parameter is used.
java.lang.Object	evaluate(Feature feature) Evaluates the expression against an instance of Feature.
int	getArgCount() Returns the number of arguments this requires.
Expression[]	getArgs() Should be an xPath of the form: featureMembers/asterisk/NAME
java.lang.String	getName() Gets the name of this function.
void	setArgs(Expression[] args) The provided arguments are evaulated with respect to the FeatureCollection.
void	setExpression(Expression e)
java.lang.String	toString() Return this function as a string.

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, 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

Collection_MaxFunction

public Collection_MaxFunction()

Creates a new instance of Collection_MaxFunction

Method Detail

getName

public 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.

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.

calculateMax

public static CalcResult calculateMax(FeatureCollection collection,
                                      Expression expression)
                               throws IllegalFilterException,
                                      java.io.IOException

Calculate maximum (using FeatureCalc) - only one parameter is used.

Parameters:

collection - collection to calculate the maximum

expression - Single Expression argument

Returns:

An object containing the maximum value of the attributes

Throws:

IllegalFilterException

java.io.IOException

setArgs

public void setArgs(Expression[] args)

The provided arguments are evaulated with respect to the FeatureCollection.

For an aggregate function (like max) please use the WFS mandated XPath syntax to refer to featureMember content.

To refer to all 'X': featureMember/asterisk/X

Specified by:

setArgs in interface FunctionExpression

Overrides:

setArgs in class FunctionExpressionImpl

Parameters:

args - DOCUMENT ME!

Throws:

java.lang.IllegalArgumentException - DOCUMENT ME!

evaluate

public 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.

setExpression

public void setExpression(Expression e)

getArgs

public Expression[] getArgs()

Should be an xPath of the form: featureMembers/asterisk/NAME

Specified by:

getArgs in interface FunctionExpression

Overrides:

getArgs in class FunctionExpressionImpl

Returns:

toString

public java.lang.String toString()

Return this function as a string.

Returns:

String representation of this max function.