com.saxonica.functions.extfn
Class GeneralFilterFunction

java.lang.Object
  net.sf.saxon.lib.ExtensionFunctionDefinition
      com.saxonica.functions.extfn.GeneralFilterFunction

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

Highest, Leading, Lowest, Sort

public abstract class GeneralFilterFunction
extends ExtensionFunctionDefinition

This class provides an abstract framework for a collection of extension functions that have the same general characteristics: (a) the first argument is a sequence, (b) the result is a subset/rearrangement of that sequence, (d) the second argument is a single argument function that is applied to the members of the sequence, (e) the default function if the second argument is omitted is fn:data(), (e) the processing may depend on the default collation.

See Also:

Serialized Form

Nested Class Summary

static class

GeneralFilterFunction.GeneralFilterFunctionCall

Constructor Summary

GeneralFilterFunction()

Method Summary

SequenceType[]	getArgumentTypes() Get the required types for the arguments of this function, counting from zero
int	getMaximumNumberOfArguments() Get the maximum number of arguments allowed by the function
int	getMinimumNumberOfArguments() Get the minimum number of arguments required by the function
SequenceType	getResultType(SequenceType[] suppliedArgumentTypes) Get the type of the result of the function

Methods inherited from class net.sf.saxon.lib.ExtensionFunctionDefinition

dependsOnFocus, getCompilerForJava, getFunctionQName, hasSideEffects, makeCallExpression, trustResultType

Methods inherited from class java.lang.Object

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

Constructor Detail

GeneralFilterFunction

public GeneralFilterFunction()

Method Detail

getMinimumNumberOfArguments

public int getMinimumNumberOfArguments()

Get the minimum number of arguments required by the function

Overrides:

getMinimumNumberOfArguments in class ExtensionFunctionDefinition

Returns:

the minimum number of arguments that must be supplied in a call to this function

getMaximumNumberOfArguments

public int getMaximumNumberOfArguments()

Get the maximum number of arguments allowed by the function

Overrides:

getMaximumNumberOfArguments in class ExtensionFunctionDefinition

Returns:

the maximum number of arguments that may be supplied in a call to this function

getArgumentTypes

public SequenceType[] getArgumentTypes()

Get the required types for the arguments of this function, counting from zero

Specified by:

getArgumentTypes in class ExtensionFunctionDefinition

Returns:

the required types of the argument, as defined by the function signature. Normally this should be an array of size getMaximumNumberOfArguments(); however for functions that allow a variable number of arguments, the array can be smaller than this, with the last entry in the array providing the required type for all the remaining arguments.

getResultType

public SequenceType getResultType(SequenceType[] suppliedArgumentTypes)

Get the type of the result of the function

Specified by:

getResultType in class ExtensionFunctionDefinition

Parameters:

suppliedArgumentTypes - the static types of the arguments to the function. This is provided so that a more precise result type can be returned in the common case where the type of the result depends on the type of the first argument. The value will be null if the function call has no arguments.

Returns:

the return type of the function, as defined by its function signature