FileDocCategorySizeDatePackage
BoundedRangeModel.javaAPI DocJava SE 6 API8409Tue Jun 10 00:26:34 BST 2008javax.swing

BoundedRangeModel

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+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.

version
1.30 03/01/06
author
Hans Muller
see
DefaultBoundedRangeModel

Fields Summary
Constructors Summary
Methods Summary
public voidaddChangeListener(javax.swing.event.ChangeListener x)
Adds a ChangeListener to the model's listener list.

param
x the ChangeListener to add
see
#removeChangeListener

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

return
the value of the model's extent property
see
#setExtent
see
#setValue

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

return
the value of the maximum property.
see
#setMaximum
see
#setExtent

public intgetMinimum()
Returns the minimum acceptable value.

return
the value of the minimum property
see
#setMinimum

public intgetValue()
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.

return
the model's value
see
#setValue

public booleangetValueIsAdjusting()
Returns true if the current changes to the value property are part of a series of changes.

return
the valueIsAdjustingProperty.
see
#setValueIsAdjusting

public voidremoveChangeListener(javax.swing.event.ChangeListener x)
Removes a ChangeListener from the model's listener list.

param
x the ChangeListener to remove
see
#addChangeListener

public voidsetExtent(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.

param
newExtent the model's new extent
see
#getExtent
see
#setValue

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

Notifies any listeners if the model changes.

param
newMaximum the model's new maximum
see
#getMaximum
see
#addChangeListener

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

Notifies any listeners if the model changes.

param
newMinimum the model's new minimum
see
#getMinimum
see
#addChangeListener

public voidsetRangeProperties(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.

param
value an int giving the current value
param
extent an int giving the amount by which the value can "jump"
param
min an int giving the minimum value
param
max an int giving the maximum value
param
adjusting a boolean, true if a series of changes are in progress
see
#setValue
see
#setExtent
see
#setMinimum
see
#setMaximum
see
#setValueIsAdjusting

public voidsetValue(int newValue)
Sets the model's current value to newValue if newValue satisfies the model's constraints. Those constraints are:
minimum <= 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.

param
newValue the model's new value
see
#getValue

public voidsetValueIsAdjusting(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.

param
b true if the upcoming changes to the value property are part of a series