com.hp.hpl.jena.graph.query
Class Expression.Base

java.lang.Object
  com.hp.hpl.jena.graph.query.Expression.Base

All Implemented Interfaces:

Expression

Direct Known Subclasses:

Expression.Application, Expression.BoolConstant, Expression.Constant, Expression.Variable

Enclosing interface:

Expression

public abstract static class Expression.Base
extends Object
implements Expression

An abstract base class for Expressions; over-ride as appropriate. The sub-classes may be more useful.

Nested Class Summary

Nested classes/interfaces inherited from interface com.hp.hpl.jena.graph.query.Expression

Expression.Application, Expression.Base, Expression.BoolConstant, Expression.Constant, Expression.Fixed, Expression.Util, Expression.Valof, Expression.Variable

Field Summary

Fields inherited from interface com.hp.hpl.jena.graph.query.Expression

FALSE, TRUE

Constructor Summary

Expression.Base()

Method Summary

int	argCount() If this Expression is an application, answer the number of arguments that it has.
boolean	equals(Object other)
Expression	getArg(int i) If this Expression is an application, and 0 <= i < argCount(), answer the ith argument.
String	getFun() If this Expression is an application, return the string identifying the function, which should be a URI.
String	getName() If this Expression is a variable, answer a [non-null] String which is its name.
Object	getValue() If this Expression is a literal, answer the value of that literal.
boolean	isApply() Answer true iff this Expression represents the application of some function [or operator] to some arguments [or operands].
boolean	isConstant() Answer true iff this Expression represents a literal [Java object] value.
boolean	isVariable() Answer true iff this Expression represents a variable.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.hp.hpl.jena.graph.query.Expression

prepare

Constructor Detail

Expression.Base

public Expression.Base()

Method Detail

isVariable

public boolean isVariable()

Description copied from interface: Expression

Answer true iff this Expression represents a variable.

Specified by:

isVariable in interface Expression

isApply

public boolean isApply()

Description copied from interface: Expression

Answer true iff this Expression represents the application of some function [or operator] to some arguments [or operands].

Specified by:

isApply in interface Expression

isConstant

public boolean isConstant()

Description copied from interface: Expression

Answer true iff this Expression represents a literal [Java object] value.

Specified by:

isConstant in interface Expression

getName

public String getName()

Description copied from interface: Expression

If this Expression is a variable, answer a [non-null] String which is its name. Otherwise the behaviour is unspecified.

Specified by:

getName in interface Expression

getValue

public Object getValue()

Description copied from interface: Expression

If this Expression is a literal, answer the value of that literal. Otherwise the behaviour is unspecified.

Specified by:

getValue in interface Expression

argCount

public int argCount()

Description copied from interface: Expression

If this Expression is an application, answer the number of arguments that it has. Otherwise the behaviour is unspecified.

Specified by:

argCount in interface Expression

getFun

public String getFun()

Description copied from interface: Expression

If this Expression is an application, return the string identifying the function, which should be a URI. Otherwise the behaviour is unspecified.

Specified by:

getFun in interface Expression

getArg

public Expression getArg(int i)

Description copied from interface: Expression

If this Expression is an application, and 0 <= i < argCount(), answer the ith argument. Otherwise the behaviour is unspecified.

Specified by:

getArg in interface Expression

equals

public boolean equals(Object other)

Overrides:

equals in class Object