org.deegree.model.filterencoding
Class Expression

java.lang.Object
  org.deegree.model.filterencoding.Expression

Direct Known Subclasses:

ArithmeticExpression, Function, Literal, PropertyName

public abstract class Expression
extends Object

Abstract superclass representing expr-entities (as defined in the Expression DTD).

Version:

$Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $

Author:

Markus Schneider, last edited by: $Author: mschneider $

Field Summary

protected int

id The underlying expression's id.

Constructor Summary

Expression()

Method Summary

static Expression	buildFromDOM(Element element) Given a DOM-fragment, a corresponding Expression-object is built.
abstract Object	evaluate(Feature feature) Calculates the Expression's value based on the certain property values of the given feature.
int	getExpressionId()
String	getExpressionName()
abstract StringBuffer	toXML() Produces an XML representation of this object.

Methods inherited from class java.lang.Object

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

Field Detail

id

protected int id

The underlying expression's id.

See Also:

ExpressionDefines

Constructor Detail

Expression

public Expression()

Method Detail

buildFromDOM

public static Expression buildFromDOM(Element element)
                               throws FilterConstructionException

Given a DOM-fragment, a corresponding Expression-object is built. This method recursively calls other buildFromDOM () - methods to validate the structure of the DOM-fragment.

Parameters:

element -

Returns:

the Bean of the DOM

Throws:

FilterConstructionException - if the structure of the DOM-fragment is invalid

getExpressionName

public String getExpressionName()

Returns:

the name of the expression.

getExpressionId

public int getExpressionId()

Returns:

the expression's id.

See Also:

ExpressionDefines

evaluate

public abstract Object evaluate(Feature feature)
                         throws FilterEvaluationException

Calculates the Expression's value based on the certain property values of the given feature.

Parameters:

feature - that determines the values of PropertyNames in the expression

Returns:

the resulting Object

Throws:

FilterEvaluationException - if the evaluation fails

toXML

public abstract StringBuffer toXML()

Produces an XML representation of this object.

Returns:

an XML representation of this object