jlibs.xml.sax.dog.expr

Class Expression

java.lang.Object

jlibs.xml.sax.dog.expr.Expression

Direct Known Subclasses:

FunctionCall, Literal, LocationExpression, PathExpression, PathExpression.HitExpression, Positional, Variable

public abstract class Expression
extends Object

The root interface in expression hierarchy.

Author:

Santhosh Kumar T

Field Summary

Fields

Modifier and Type	Field and Description
int	id Only doc scope expression have this filed set.
DataType	resultType
protected int	scope
boolean	storeResult tells whether Event should store the result of this expression Note: this is used only for doc scope expression
protected String	xpath only user given have xpath set.

Constructor Summary

Constructors

Constructor and Description
Expression(int scope, DataType resultType)

Method Summary

Modifier and Type	Method and Description
abstract Object	getResult() This method is called only glocal scope expression
abstract Object	getResult(Event event) This method is called only non-glocal scope expression.
String	getXPath()
int	scope()
void	setXPath(String xpath)
Expression	simplify() returns simplified expression which peforms better.

Methods inherited from class java.lang.Object

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

Field Detail

id

public int id

Only doc scope expression have this filed set. All doc level expression in a xmldog instance are assigned unique number sequentially.

See Also:

assigns unique sequential id. this id used by:, array to manage listeners for expression, array to manage result for expression

resultType

public final DataType resultType

scope

protected int scope

storeResult

public boolean storeResult

tells whether Event should store the result of this expression Note: this is used only for doc scope expression

xpath

protected String xpath

only user given have xpath set.

Constructor Detail

Expression

public Expression(int scope,
                  DataType resultType)

Method Detail

scope

public final int scope()

See Also:

Scope

getResult

public abstract Object getResult()

This method is called only glocal scope expression

getResult

public abstract Object getResult(Event event)

This method is called only non-glocal scope expression. it can return the result if it is possible, otherwize returns Evaluation object.

simplify

public Expression simplify()

returns simplified expression which peforms better. if no simpliciation possible it simply returns current expression. default implementation promotes global-scoped expressions to literal

setXPath

public final void setXPath(String xpath)

getXPath

public final String getXPath()