Package weka.core.expressionlanguage.common

Class JavaMacro

java.lang.Object

weka.core.expressionlanguage.common.JavaMacro

All Implemented Interfaces:

Macro, MacroDeclarations

public class JavaMacro
extends Object
implements MacroDeclarations, Macro

A macro declarations that exposes the java macro to a program.

The java macro can be used as follows
java(class, signature, arguments)

Where class is the name of class, signature is the signature of the function and arguments is a list of arguments passed to the java function.

The signature follows the pattern:
type name '(' [ type [ ',' type ]* ] ')'
where type is one of 'boolean', 'double' or 'String' and name must be a valid java identifier.

Examples:

• java('java.lang.Math', 'double sqrt(double)', 4.0)
• java('java.lang.String', 'String valueOf(double)', 2^30)

Version:

$Revision: 1000 $

Author:

Benjamin Weber ( benweber at student dot ethz dot ch )

Constructor Summary

Constructors

Constructor	Description
JavaMacro()

Method Summary

Modifier and Type	Method	Description
Node	evaluate(Node... nodes)	Evaluates the java macro on the given arguments
Macro	getMacro(String name)	Tries to fetch the macro
boolean	hasMacro(String name)	Whether the macro declarations contains the macro

Methods inherited from class java.lang.Object

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

Constructor Details

JavaMacro

public JavaMacro()

Method Details

evaluate

public Node evaluate(Node... nodes)
              throws SemanticException

Evaluates the java macro on the given arguments

Specified by:

evaluate in interface Macro

Parameters:

nodes - the arguments to the java macro

Returns:

an AST node returned by the macro

Throws:

SemanticException

hasMacro

public boolean hasMacro(String name)

Whether the macro declarations contains the macro

Specified by:

hasMacro in interface MacroDeclarations

Parameters:

name - name of the macro

Returns:

whether the macro is declared

getMacro

public Macro getMacro(String name)

Description copied from interface: MacroDeclarations

Tries to fetch the macro

Before a macro is fetched it shold be checked whether it is declared through MacroDeclarations.hasMacro(String)

Specified by:

getMacro in interface MacroDeclarations

Returns: