javax.swing
Interface BoundedRangeModel

All Known Implementing Classes:

DefaultBoundedRangeModel

public interface BoundedRangeModel

Defines the data model used by components like Sliders and ProgressBars. Defines four interrelated integer properties: minimum, maximum, extent and value. These four integers define two nested ranges like this:

 minimum <= value="value" <="value+extent" <="maximum" 
 The outer range is minimum,maximum and the inner
 range is value,value+extent.  The inner range
 must lie within the outer one, i.e. value must be 
 less than or equal to maximum and value+extent
 must greater than or equal to minimum, and maximum
 must be greater than or equal to minimum.
 There are a few features of this model that one might find a little 
 surprising.  These quirks exist for the convenience of the
 Swing BoundedRangeModel clients, such as Slider and
 ScrollBar.
 

 
 
   The minimum and maximum set methods "correct" the other 
   three properties to accommodate their new value argument.  For 
   example setting the model's minimum may change its maximum, value,
   and extent properties (in that order), to maintain the constraints
   specified above.  
 
 

   The value and extent set methods "correct" their argument to 
   fit within the limits defined by the other three properties.  
   For example if value == maximum, setExtent(10)
   would change the extent (back) to zero.
 
 
 
   The four BoundedRangeModel values are defined as Java Beans properties
   however Swing ChangeEvents are used to notify clients of changes rather
   than PropertyChangeEvents. This was done to keep the overhead of monitoring
   a BoundedRangeModel low. Changes are often reported at MouseDragged rates. 
 

 

 
 For an example of specifying custom bounded range models used by sliders,
 see The Anatomy of a Swing-Based Program
 in The Java Tutorial.




See Also:
DefaultBoundedRangeModel







Method Summary




 void
addChangeListener(ChangeListener x)



          Adds a ChangeListener to the model's listener list.



 int
getExtent()



          Returns the model's extent, the length of the inner range that
 begins at the model's value.



 int
getMaximum()



          Returns the model's maximum.



 int
getMinimum()



          Returns the minimum acceptable value.



 int
getValue()



          Returns the model's current value.



 boolean
getValueIsAdjusting()



          Returns true if the current changes to the value property are part 
 of a series of changes.



 void
removeChangeListener(ChangeListener x)



          Removes a ChangeListener from the model's listener list.



 void
setExtent(int newExtent)



          Sets the model's extent.



 void
setMaximum(int newMaximum)



          Sets the model's maximum to newMaximum.



 void
setMinimum(int newMinimum)



          Sets the model's minimum to newMinimum.



 void
setRangeProperties(int value,
                   int extent,
                   int min,
                   int max,
                   boolean adjusting)



          This method sets all of the model's data with a single method call.



 void
setValue(int newValue)



          Sets the model's current value to newValue if newValue
 satisfies the model's constraints.



 void
setValueIsAdjusting(boolean b)



          This attribute indicates that any upcoming changes to the value
 of the model should be considered a single event.


 





Method Detail



getMinimum
int getMinimum()

Returns the minimum acceptable value.



Returns:
the value of the minimum property
See Also:
setMinimum(int)





setMinimum
void setMinimum(int newMinimum)

Sets the model's minimum to newMinimum.   The 
 other three properties may be changed as well, to ensure 
 that:
 
 minimum <= value="value" <="value+extent" <="maximum" 
 

 Notifies any listeners if the model changes.


Parameters:
newMinimum - the model's new minimum
See Also:
getMinimum(), 
addChangeListener(javax.swing.event.ChangeListener)





getMaximum
int getMaximum()

Returns the model's maximum.  Note that the upper
 limit on the model's value is (maximum - extent).



Returns:
the value of the maximum property.
See Also:
setMaximum(int), 
setExtent(int)





setMaximum
void setMaximum(int newMaximum)

Sets the model's maximum to newMaximum. The other 
 three properties may be changed as well, to ensure that
 
 minimum <= value="value" <="value+extent" <="maximum" 
 

 Notifies any listeners if the model changes.


Parameters:
newMaximum - the model's new maximum
See Also:
getMaximum(), 
addChangeListener(javax.swing.event.ChangeListener)





getValue
int getValue()

Returns the model's current value.  Note that the upper
 limit on the model's value is maximum - extent 
 and the lower limit is minimum.



Returns:
the model's value
See Also:
setValue(int)





setValue
void setValue(int newValue)

Sets the model's current value to newValue if newValue
 satisfies the model's constraints. Those constraints are:
 
 minimum <= value="value" <="value+extent" <="maximum" 
 Otherwise, if newValue is less than minimum 
 it's set to minimum, if its greater than 
 maximum then it's set to maximum, and 
 if it's greater than value+extent then it's set to 
 value+extent.
 

 When a BoundedRange model is used with a scrollbar the value
 specifies the origin of the scrollbar knob (aka the "thumb" or
 "elevator").  The value usually represents the origin of the 
 visible part of the object being scrolled.
 

 Notifies any listeners if the model changes.


Parameters:
newValue - the model's new value
See Also:
getValue()





setValueIsAdjusting
void setValueIsAdjusting(boolean b)

This attribute indicates that any upcoming changes to the value
 of the model should be considered a single event. This attribute
 will be set to true at the start of a series of changes to the value,
 and will be set to false when the value has finished changing.  Normally
 this allows a listener to only take action when the final value change in
 committed, instead of having to do updates for all intermediate values.
 

 Sliders and scrollbars use this property when a drag is underway.


Parameters:
b - true if the upcoming changes to the value property are part of a series





getValueIsAdjusting
boolean getValueIsAdjusting()

Returns true if the current changes to the value property are part 
 of a series of changes.



Returns:
the valueIsAdjustingProperty.
See Also:
setValueIsAdjusting(boolean)





getExtent
int getExtent()

Returns the model's extent, the length of the inner range that
 begins at the model's value.



Returns:
the value of the model's extent property
See Also:
setExtent(int), 
setValue(int)





setExtent
void setExtent(int newExtent)

Sets the model's extent.  The newExtent is forced to 
 be greater than or equal to zero and less than or equal to
 maximum - value.   
 

 When a BoundedRange model is used with a scrollbar the extent
 defines the length of the scrollbar knob (aka the "thumb" or
 "elevator").  The extent usually represents how much of the 
 object being scrolled is visible. When used with a slider,
 the extent determines how much the value can "jump", for
 example when the user presses PgUp or PgDn.
 

 Notifies any listeners if the model changes.


Parameters:
newExtent - the model's new extent
See Also:
getExtent(), 
setValue(int)





setRangeProperties
void setRangeProperties(int value,
                        int extent,
                        int min,
                        int max,
                        boolean adjusting)

This method sets all of the model's data with a single method call.
 The method results in a single change event being generated. This is
 convenient when you need to adjust all the model data simultaneously and
 do not want individual change events to occur.


Parameters:
value - an int giving the current value
extent - an int giving the amount by which the value can "jump"
min - an int giving the minimum value
max - an int giving the maximum value
adjusting - a boolean, true if a series of changes are in
                    progress
See Also:
setValue(int), 
setExtent(int), 
setMinimum(int), 
setMaximum(int), 
setValueIsAdjusting(boolean)





addChangeListener
void addChangeListener(ChangeListener x)

Adds a ChangeListener to the model's listener list.


Parameters:
x - the ChangeListener to add
See Also:
removeChangeListener(javax.swing.event.ChangeListener)





removeChangeListener
void removeChangeListener(ChangeListener x)

Removes a ChangeListener from the model's listener list.


Parameters:
x - the ChangeListener to remove
See Also:
addChangeListener(javax.swing.event.ChangeListener)