Analytical Perspectives in Game Design

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Class bvyy.smf.DiscreteLinearStateModel

java.lang.Object
   |
   +----bvyy.smf.StateMachine
           |
           +----bvyy.smf.DiscreteLinearStateModel

public class DiscreteLinearStateModel

extends StateMachine

Make a state machine in the manner of a linked list. This is a flyweight pattern.

Intent

To implement a state machine for linear models. (For exampe a numeric list, where you can move along the list by n items.)

Motivation

To reduce the number of classes required for this specific type of state machine and hence improve performance. State is recorded as an interger rather than a series of state classes.

Version:

1.0.2 24 May 1998

Author:

(c) 1998 Brian Voon Yee Yap

See Also:

ContinuousLinearStateModel

DiscreteLinearStateModel()

DiscreteLinearStateModel(String)

Construct a state machine.

fireStateChange(ModifiableChangeEvent)

Change the state from the current state to a new state.

getDefaultValue()

Get the default value.

getDownVerb()

Gets the down verb.

getMax()

Get maximum value

getMin()

Get minimum value

getState()

Returns the current state of the state machine in a StringTokenizer.

getStateTransitions()

Gets the states that can be reached from the current state.

getUpVerb()

Gets the up verb.

setDefaultValue(int)

Set the default value.

setDownVerb(String)

Sets the down verb.

setMax(int)

Set maximum value.

setMin(int)

Set minimum value.

If the current value, or default values are less than the new minimum they will be set to the new minimum.

setUpVerb(String)

Sets the up verb.

 public DiscreteLinearStateModel()

 public DiscreteLinearStateModel(String spec)

Construct a state machine.

This method is synchronised to prevent conflicts from other clients who might want to update the state of this machine. They will have to wait until after the object is created.

Parameters:

spec - The format of the input token shall be:

• LSM,[major version],[minor version]
• name
• defaultvalue
• maxValue
• minvalue
• upVerb
• downVerb

The delimeter is |.

 public void fireStateChange(ModifiableChangeEvent newState) throws PropertyVetoException

Change the state from the current state to a new state. If the state request is not possible then no transition happens. This might happen in a multi-user game where another user has acted just before this user.

Modifiers are not implemented in this version.

Parameters:

newState - is a property change event. The old and new value objects should be string objects.

Throws: PropertyVetoException

thrown if a vetoable listener vetoes the change.

Overrides:

fireStateChange in class StateMachine

 public String getState()

Returns the current state of the state machine in a StringTokenizer.

The format of the StringTokenizer is:

• myName,[major version],[minor version]
• myvalue

Overrides:

getState in class StateMachine

 public String getStateTransitions()

Gets the states that can be reached from the current state. A StringTokenizer of new states is returned.

The format of the StringTokenizer is:

• LSM,[major version],[minor version]
• name
• currentvalue
• maxValue
• minvalue
• upVerb
• downVerb

The delimeter is "|".

Overrides:

getStateTransitions in class StateMachine

 public void setDefaultValue(int newDefault)

Set the default value.

Parameters:

newDefault - The default is set to this value unless it is outside the maximum or minimum value. The it is set to the maximum or minimum value.

 public int getDefaultValue()

Get the default value.

 public void setMax(int newMax)

Set maximum value.

If the current value, or default values are greater than the new maximum they will be set to the new maximum. This in turn will fire any necessary validations. If this change is voided, then nothing is done.

If the maxvalue is below the minimum value then the maximum value will be set to the minimum value.

Parameters:

newMax - The new maximum value.

 public int getMax()

Get maximum value

 public void setMin(int newMin)

Set minimum value.

If the current value, or default values are less than the new minimum they will be set to the new minimum. This in turn will fire any necessary validations. If this change is voided, then nothing is done.

If you attempt to set the minimum above the maximum, it will be set to the maximum.

Parameters:

newMin - The new minimum value.

 public int getMin()

Get minimum value

 public void setUpVerb(String newUpVerb)

Sets the up verb.

Parameters:

newUpVerb - the new verb.

 public String getUpVerb()

Gets the up verb.

 public void setDownVerb(String newDownVerb)

Sets the down verb.

Parameters:

newDownVerb - the new verb.

 public String getDownVerb()

Gets the down verb.

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22/11/99

See also: [Role Playing Games] [Game Engine]
© 1998, 1999 Brian Yap. These pages are available under the GNU licence.