uk.ac.sheffield.vtts.model

Class Alphabet

java.lang.Object

uk.ac.sheffield.vtts.model.Element

uk.ac.sheffield.vtts.model.Alphabet

public class Alphabet
extends Element

Alphabet represents the complete set of events recognised by a machine. The Alphabet of a Machine is created by exploring all the Transitions of a Machine and including an Event for each labelled Transition. The Alphabet is used to construct Languages of different lengths, the basis for sequences presented to a Machine. The Alphabet of a Protocol is calculated by exploring all the Operations and Scenarios in the Protocol and including an Event for each labelled Scenario. Alphabets may be compared, to see whether the Machine and the Protocol handle the same set of Events.

Version:

Broker@Cloud 1.0

Author:

Anthony J H Simons

Constructor Summary

Constructors

Constructor and Description
Alphabet() Creates an empty Alphabet.

Method Summary

Methods

Modifier and Type	Method and Description
Alphabet	addEvent(Event event) Adds an event to this alphabet.
java.util.Set<Event>	getEvents() Returns the set of events in this alphabet.
boolean	isEmpty() Reports whether this Alphabet is empty.
int	size() Returns the size of this alphabet.
Alphabet	subtract(Alphabet other) Computes the difference between this and the other Alphabet.

Methods inherited from class uk.ac.sheffield.vtts.model.Element

safeEquals, safeHashCode, semanticError

Methods inherited from class java.lang.Object

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

Constructor Detail

Alphabet

public Alphabet()

Creates an empty Alphabet.

Method Detail

isEmpty

public boolean isEmpty()

Reports whether this Alphabet is empty.

Returns:

true if this Alphabet is empty.

size

public int size()

Returns the size of this alphabet.

Returns:

the number of distinct events.

addEvent

public Alphabet addEvent(Event event)

Adds an event to this alphabet. If this alphabet does not already contain an event equal to the added event, it includes the new event in its set of events.

Parameters:

event - the event.

Returns:

this alphabet.

getEvents

public java.util.Set<Event> getEvents()

Returns the set of events in this alphabet.

Returns:

the set of events.

subtract

public Alphabet subtract(Alphabet other)

Computes the difference between this and the other Alphabet. This is used when comparing two Alphabets for consistency. The result is a new Alphabet, containing the Events from this Alphabet that were not found in the other Alphabet.

Parameters:

other - the other Alphabet.

Returns:

the Alphabet representing the difference.