yass.state
Class StateTransition<T extends State>

java.lang.Object
  yass.state.StateTransition<T>

All Implemented Interfaces:

java.lang.Comparable

public class StateTransition<T extends State>
extends java.lang.Object
implements java.lang.Comparable

Encapsulates a generic state transition

Field Summary

private T	from The previous state
private double	timestamp The state transition timestamp
private T	to The new state

Constructor Summary

StateTransition(T from, T to, double timestamp)
Constructs a new instance of StateTransition

Method Summary

int	compareTo(java.lang.Object object) Compares an arbitrary object to this StateTransition, and calculates their relationship in accordance with the natural ordering of StateTransition objects.
boolean	equals(java.lang.Object o) Determines if a supplied object is equal to this StateTransition.
T	getFromState() Obtains the previous state
double	getTimestamp() Obtains the state transition timestamp
T	getToState() Obtains the new state
int	hashCode() Obtains a hashcode value
java.lang.String	toString() Obtains a textual representation of the state transition

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

from

private T extends State from

The previous state

to

private T extends State to

The new state

timestamp

private double timestamp

The state transition timestamp

Constructor Detail

StateTransition

public StateTransition(T from,
                       T to,
                       double timestamp)

Constructs a new instance of StateTransition

Parameters:

timestamp - the state transition timestamp

from - the previous state

to - the new state

Method Detail

toString

public java.lang.String toString()

Obtains a textual representation of the state transition

Overrides:

toString in class java.lang.Object

Returns:

a textual representation of the state transition

hashCode

public int hashCode()

Obtains a hashcode value

Overrides:

hashCode in class java.lang.Object

Returns:

a hashcode value

equals

public boolean equals(java.lang.Object o)

Determines if a supplied object is equal to this StateTransition. Only the identity of the pre/post transition states are considered; the timestamp is ignored.

Overrides:

equals in class java.lang.Object

Parameters:

o - the object to compare

Returns:

true if the supplied object is equal to this StateTransition, otherwise false

compareTo

public int compareTo(java.lang.Object object)

Compares an arbitrary object to this StateTransition, and calculates their relationship in accordance with the natural ordering of StateTransition objects. This natural ordering is based mainly on timestamp. However, if two timestamps are exactly equal, tie-breaking will use state hashcodes to ensure that compareTo() results are consistent with equals() results. Tie-breaking will first compare the "from" state hashcodes, and then the "to" state hashcodes if the "from" state hashcodes were also equal. If all three of the timestamp, "from" state, and "to" state, are all equal, then both state transitions are equal. Note that the specified arbitrary object will be cast as a StateTransition which will generate a runtime exception if it is not actually a StateTransition. This is necessary because the current release of Java has an implementation of generic classes which cannot cope with this class implementing Comparable>.

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

object - the object to compare

Returns:

-ve if this StateTransition is less than the arbitrary object, 0 if this StateTransition is equal to the arbitrary object, or +ve if this StateTransition is greater than the arbitrary object

getFromState

public T getFromState()

Obtains the previous state

Returns:

the previous state

getToState

public T getToState()

Obtains the new state

Returns:

the new state

getTimestamp

public double getTimestamp()

Obtains the state transition timestamp

Returns:

the state transition timestamp