com.saxonica.functions.extfn
Class ForEachGroupFunction

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

All Implemented Interfaces:

Serializable

public class ForEachGroupFunction
extends ExtensionFunctionDefinition

This class implements the extension function saxon:for-each-group(). This is a higher order function that provides grouping capability. Its effect is similar to the XSLT 2.0 for-each-group instruction, but it works also in XQuery. The first argument is the population to be grouped; the second argument is a function that calculates the grouping key; the third argument is the action to be performed on each group: it gets the members of the group as its argument.

See Also:

Serialized Form

Constructor Summary

ForEachGroupFunction()

Method Summary

SequenceType[]	getArgumentTypes() Get the required types for the arguments of this function, counting from zero
StructuredQName	getFunctionQName() Get the function name, as a QName
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
ExtensionFunctionCall	makeCallExpression() Create a call on this function.

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

dependsOnFocus, hasSideEffects, trustResultType

Methods inherited from class java.lang.Object

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

Constructor Detail

ForEachGroupFunction

public ForEachGroupFunction()

Method Detail

getFunctionQName

public StructuredQName getFunctionQName()

Get the function name, as a QName

Specified by:

getFunctionQName in class ExtensionFunctionDefinition

Returns:

the QName of the function

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

makeCallExpression

public ExtensionFunctionCall makeCallExpression()

Create a call on this function. This method is called by the compiler when it identifies a function call that calls this function.

Specified by:

makeCallExpression in class ExtensionFunctionDefinition

Returns:

an expression representing a call of this extension function