com.rubecula.util
Class Symbol

java.lang.Object
  com.rubecula.util.Symbol

All Implemented Interfaces:

Presentable

Direct Known Subclasses:

Operator

public class Symbol

extends java.lang.Object

implements Presentable

Symbol Class. This class is used to model non-numerical objects which appear in expressions, such as operators, variable references, parentheses, etc.

Copyright: Copyright (c) 2003

Company: Rubecula Software

Since:

V_0_3

Version:

$Revision: 1.3 $

Author:

Robin Hillyard

Field Summary

protected java.lang.String

_S

Constructor Summary

Symbol(java.lang.String s)

Method Summary

java.lang.String	getType() This method is primarily for development purposes: it yields the name of the class of the presentable object or, in some cases, the class of the presentable object indirectly referenced.
Presentable	makePresentableInstance(Presentation presentation) Instance method to convert a Presentation into a Presentable.
Presentation	present(AttrMap attributes) Convert this Presentable object into a Presentation, according to the set of attributes provided.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

_S

protected final java.lang.String _S

Constructor Detail

Symbol

public Symbol(java.lang.String s)

Method Detail

toString

public java.lang.String toString()

present

public Presentation present(AttrMap attributes)
                     throws PresentationException

Description copied from interface: Presentable

Convert this Presentable object into a Presentation, according to the set of attributes provided.

Specified by:

present in interface Presentable

Parameters:

attributes - a map of the attributes desired for the construction of the new presentation (may be empty).

Returns:

an appropriate instance of Presentation.

Throws:

PresentationException - in case of parsing error.

getType

public java.lang.String getType()

This method is primarily for development purposes: it yields the name of the class of the presentable object or, in some cases, the class of the presentable object indirectly referenced. The text returned is canonical class name (subclasses may choose to override this).

Specified by:

getType in interface Presentable

Returns:

a representation of the effective class of this object.

makePresentableInstance

public Presentable makePresentableInstance(Presentation presentation)
                                    throws PresentationException

Description copied from interface: Presentable

Instance method to convert a Presentation into a Presentable. Ideally, this would be a class method, but such a method cannot be defined in an interface. Nor can it be defined in an abstract class with the intention of overriding it in a subclass. Polymorphism just doesn't work that way.
Therefore, the present value (as in fields) of the instance is essentially ignored - only the methods are important.

Specified by:

makePresentableInstance in interface Presentable

Parameters:

presentation - of a number to be converted into a Presentable number.

Returns:

a number in the form of a Presentable.

Throws:

PresentationException - in case of parsing error.