com.hp.hpl.jena.graph.query
Class Dyadic

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

All Implemented Interfaces:

Expression

Direct Known Subclasses:

Rewrite.DyadicLiteral

public abstract class Dyadic
extends Expression.Application

A base class for dyadic expressions with a built-in Valuator; subclasses must define an evalObject or evalBool method which will be supplied with the evaluated operands.

Author:

kers

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

Dyadic(Expression L, String F, Expression R)

Method Summary

static Expression	and(Expression L, Expression R)
int	argCount() If this Expression is an application, answer the number of arguments that it has.
boolean	evalBool(Object l, Object r) Answer the boolean result of evaluating this dyadic expression with the given arguments l and r.
Object	evalObject(Object l, Object r) Answer the Object result of evaluating this dyadic expression with the given arguments l and r.
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.
Valuator	prepare(VariableIndexes vi) Answer a Valuator which, when run with a set of index-to-value bindings, evaluates this expression in the light of the given variable-to-index bindings [ie as though the variables were bound to the corresponding values]
String	toString()

Methods inherited from class com.hp.hpl.jena.graph.query.Expression.Application

isApply

Methods inherited from class com.hp.hpl.jena.graph.query.Expression.Base

equals, getName, getValue, isConstant, isVariable

Methods inherited from class java.lang.Object

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

Constructor Detail

Dyadic

public Dyadic(Expression L,
              String F,
              Expression R)

Method Detail

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

Specified by:

argCount in class Expression.Application

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

Specified by:

getArg in class Expression.Application

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

Specified by:

getFun in class Expression.Application

evalObject

public Object evalObject(Object l,
                         Object r)

Answer the Object result of evaluating this dyadic expression with the given arguments l and r. Either this method or evalBool must be over-ridden in concrete sub-classes.

evalBool

public boolean evalBool(Object l,
                        Object r)

Answer the boolean result of evaluating this dyadic expression with the given arguments l and r. Either this method or evalObject must be over-ridden in concrete sub-classes.

prepare

public Valuator prepare(VariableIndexes vi)

Description copied from interface: Expression

Answer a Valuator which, when run with a set of index-to-value bindings, evaluates this expression in the light of the given variable-to-index bindings [ie as though the variables were bound to the corresponding values]

toString

public String toString()

Overrides:

toString in class Object

and

public static Expression and(Expression L,
                             Expression R)