nextgrid.api.pom
Class Expression

java.lang.Object
  nextgrid.api.pom.Expression

All Implemented Interfaces:

java.io.Serializable

public abstract class Expression
extends java.lang.Object
implements java.io.Serializable

Expression wrapper. Each subclass is responsible of implementing a specific language syntax.

Expressions are immutable objects. Their contents cannot be changed after construction, and a new instance must be created if a modification is required.

Author:

Rodrigo Ruiz

See Also:

Serialized Form

Constructor Summary

protected

Expression(java.lang.String lang, java.lang.String text) Creates a new instance.

Method Summary

abstract boolean	boolEval(ProcessEnvironment env, java.lang.Object o) Evaluate this XPath expression as a boolean.
java.lang.String	getLang() Gets the language of this expression.
java.lang.String	getText() Gets the text value.
abstract void	validate() Checks that the expression is valid.

Methods inherited from class java.lang.Object

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

Constructor Detail

Expression

protected Expression(java.lang.String lang,
                     java.lang.String text)
              throws ExpressionException

Creates a new instance.

Parameters:

lang - The expression language

text - The expression text

Throws:

ExpressionException - If an error occurs

Method Detail

getLang

public final java.lang.String getLang()

Gets the language of this expression.

Returns:

The language name for this expression

getText

public final java.lang.String getText()

Gets the text value.

Returns:

The text

validate

public abstract void validate()
                       throws ExpressionException

Checks that the expression is valid.

Throws:

ExpressionException - If the validation fails

boolEval

public abstract boolean boolEval(ProcessEnvironment env,
                                 java.lang.Object o)
                          throws ExpressionException

Evaluate this XPath expression as a boolean.

Parameters:

env - Environment for global configuration

o - The node set where the expression is to be evaluated

Returns:

The evaluation result

Throws:

ExpressionException - If an error occurs