weka.core.expressionlanguage.common

Class VariableDeclarationsCompositor

java.lang.Object

weka.core.expressionlanguage.common.VariableDeclarationsCompositor

All Implemented Interfaces:

java.io.Serializable, VariableDeclarations

public class VariableDeclarationsCompositor
extends java.lang.Object
implements VariableDeclarations

A helper class that allows to combine several variable declarations together.

It can be thought of as layering several scopes over one another.

It will delegate the hasVariable(String) and getVariable(String) methods to other variable declarations.

Each variable declaration combined is checked in sequential order.

No checks for conflicts are done. Thus shadowing is possible.

Version:

$Revision: 1000 $

Author:

Benjamin Weber ( benweber at student dot ethz dot ch )

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
VariableDeclarationsCompositor(VariableDeclarations... declarations) Constructs a VariableDeclarationsCompositor containing the provided declarations

Method Summary

Modifier and Type	Method and Description
Node	getVariable(java.lang.String name) Tries to fetch a variable from one of the combined declarations.
boolean	hasVariable(java.lang.String name) Whether the variable is contained in one of the combined declarations.

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableDeclarationsCompositor

public VariableDeclarationsCompositor(VariableDeclarations... declarations)

Constructs a VariableDeclarationsCompositor containing the provided declarations

The order of the declarations will determine the order of checking the declarations for variables.

Parameters:

declarations - the declarations being combined

Method Detail

hasVariable

public boolean hasVariable(java.lang.String name)

Whether the variable is contained in one of the combined declarations.

Specified by:

hasVariable in interface VariableDeclarations

Parameters:

name - name of the variable

Returns:

whether the variable is contained in one of the combined declarations

getVariable

public Node getVariable(java.lang.String name)

Tries to fetch a variable from one of the combined declarations.

The same invariant of VariableDeclarations applies here too.

Specified by:

getVariable in interface VariableDeclarations

Parameters:

name - the name of the variable to be fetched

Returns:

an AST (abstract syntax tree) node representing the variable