BoundedRangeModel (Java SE 14 & JDK 14)
Description: declaration: module: java.desktop, package: javax.swing, interface: BoundedRangeModel
Keywords: javax.swing.BoundedRangeModel interface

Module java.desktop
Package javax.swing

# Interface BoundedRangeModel

All Known Implementing Classes:
  `DefaultBoundedRangeModel`

    public interface BoundedRangeModel

Defines the data model used by components like `Slider`s and `ProgressBar`s. 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 Separable model architecture in A Swing Architecture Overview.

Since:
  1.2
See Also:
  `DefaultBoundedRangeModel`

- ## Method Summary

  Modifier and Type | Method | Description
  --- | --- | ---
  `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 Details

  - ### 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+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+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+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)`