org.apache.commons.scxml
Interface Evaluator

All Known Implementing Classes:

ELEvaluator, JexlEvaluator

public interface Evaluator

Interface for a component that may be used by the SCXML engines to evaluate the expressions within the SCXML document.

Method Summary

Object	eval(Context ctx, String expr) Evaluate an expression.
Boolean	evalCond(Context ctx, String expr) Evaluate a condition.
Node	evalLocation(Context ctx, String expr) Evaluate a location that returns a Node within an XML data tree.
Context	newContext(Context parent) Create a new child context.

Method Detail

eval

Object eval(Context ctx,
            String expr)
            throws SCXMLExpressionException

Evaluate an expression.

Parameters:

ctx - variable context

expr - expression

Returns:

a result of the evaluation

Throws:

SCXMLExpressionException - A malformed exception

evalCond

Boolean evalCond(Context ctx,
                 String expr)
                 throws SCXMLExpressionException

Evaluate a condition. Manifests as "cond" attributes of <transition>, <if> and <elseif> elements.

Parameters:

ctx - variable context

expr - expression

Returns:

true/false

Throws:

SCXMLExpressionException - A malformed exception

evalLocation

Node evalLocation(Context ctx,
                  String expr)
                  throws SCXMLExpressionException

Evaluate a location that returns a Node within an XML data tree. Manifests as "location" attributes of <assign> element.

Parameters:

ctx - variable context

expr - expression

Returns:

The location node.

Throws:

SCXMLExpressionException - A malformed exception

newContext

Context newContext(Context parent)

Create a new child context.

Parameters:

parent - parent context

Returns:

new child context