mondrian.spi

Interface UserDefinedFunction

All Known Implementing Classes:

CurrentDateMemberExactUdf, CurrentDateMemberUdf, CurrentDateStringUdf, InUdf, InverseNormalUdf, LastNonEmptyUdf, MatchesUdf, NullValueUdf, ValUdf

public interface UserDefinedFunction

Definition of a user-defined function.

The class must have a public, zero-arguments constructor, be on Mondrian's runtime class-path, and be referenced from the schema file:

<Schema>
....
<UserDefinedFunction name="MyFun" class="com.acme.MyFun">
</Schema>

Author:

jhyde

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	UserDefinedFunction.Argument

Method Summary

Modifier and Type	Method and Description
Object	execute(Evaluator evaluator, UserDefinedFunction.Argument[] arguments) Applies this function to a set of arguments, and returns a result.
String	getDescription() Returns a description of the user-defined function.
String	getName() Returns the name with which the user-defined function will be used from within MDX expressions.
Type[]	getParameterTypes() Returns an array of the types of the parameters of this function.
String[]	getReservedWords() Returns a list of reserved words used by this function.
Type	getReturnType(Type[] parameterTypes) Returns the return-type of this function.
Syntax	getSyntax() Returns the syntactic type of the user-defined function.

Method Detail

getName

String getName()

Returns the name with which the user-defined function will be used from within MDX expressions.

getDescription

String getDescription()

Returns a description of the user-defined function.

getSyntax

Syntax getSyntax()

Returns the syntactic type of the user-defined function. Usually Syntax.Function.

getParameterTypes

Type[] getParameterTypes()

Returns an array of the types of the parameters of this function.

getReturnType

Type getReturnType(Type[] parameterTypes)

Returns the return-type of this function.

Parameters:

parameterTypes - Parameter types

Returns:

Return type

execute

Object execute(Evaluator evaluator,
               UserDefinedFunction.Argument[] arguments)

Applies this function to a set of arguments, and returns a result.

Parameters:

evaluator - Evaluator containts the runtime context, in particular the current member of each dimension.

arguments - Expressions which yield the arguments of this function. Most user-defined functions will evaluate all arguments before using them. Functions such as IIf do not evaluate all arguments; this technique is called lazy evaluation.

Returns:

The result value.

getReservedWords

String[] getReservedWords()

Returns a list of reserved words used by this function. May return an empty array or null if this function does not require any reserved words.