# Interface ListSelectionModel

All Known Implementing Classes:
  `DefaultListSelectionModel`

public interface ListSelectionModel
This interface represents the current state of the selection for any of the components that display a list of values with stable indices. The selection is modeled as a set of intervals, each interval represents a contiguous range of selected list elements. The methods for modifying the set of selected intervals all take a pair of indices, index0 and index1, that represent a closed interval, i.e. the interval includes both index0 and index1.

Since:
  1.2
See Also:
  - `DefaultListSelectionModel`

## Field Summary

Fields
Modifier and Type
Field
Description
`static final int`
`MULTIPLE_INTERVAL_SELECTION`
A value for the selectionMode property: select one or more contiguous ranges of indices at a time.
`static final int`
`SINGLE_INTERVAL_SELECTION`
A value for the selectionMode property: select one contiguous range of indices at a time.
`static final int`
`SINGLE_SELECTION`
A value for the selectionMode property: select one list index at a time.

## Method Summary

Modifier and Type
Method
Description
`void`
`addListSelectionListener(ListSelectionListener x)`
Add a listener to the list that's notified each time a change to the selection occurs.
`void`
`addSelectionInterval(int index0, int index1)`
Changes the selection to be the set union of the current selection and the indices between `index0` and `index1` inclusive.
`void`
`clearSelection()`
Change the selection to the empty set.
`int`
`getAnchorSelectionIndex()`
Return the first index argument from the most recent call to setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().
`int`
`getLeadSelectionIndex()`
Return the second index argument from the most recent call to setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().
`int`
`getMaxSelectionIndex()`
Returns the last selected index or -1 if the selection is empty.
`int`
`getMinSelectionIndex()`
Returns the first selected index or -1 if the selection is empty.
`default int[]`
`getSelectedIndices()`
Returns an array of all of the selected indices in the selection model, in increasing order.
`default int`
`getSelectedItemsCount()`
Returns the number of selected items.
`int`
`getSelectionMode()`
Returns the current selection mode.
`boolean`
`getValueIsAdjusting()`
Returns `true` if the selection is undergoing a series of changes.
`void`
`insertIndexInterval(int index, int length, boolean before)`
Insert `length` indices beginning before/after `index`.
`boolean`
`isSelectedIndex(int index)`
Returns true if the specified index is selected.
`boolean`
`isSelectionEmpty()`
Returns true if no indices are selected.
`void`
`removeIndexInterval(int index0, int index1)`
Remove the indices in the interval `index0,index1` (inclusive) from the selection model.
`void`
`removeListSelectionListener(ListSelectionListener x)`
Remove a listener from the list that's notified each time a change to the selection occurs.
`void`
`removeSelectionInterval(int index0, int index1)`
Changes the selection to be the set difference of the current selection and the indices between `index0` and `index1` inclusive.
`void`
`setAnchorSelectionIndex(int index)`
Set the anchor selection index.
`void`
`setLeadSelectionIndex(int index)`
Set the lead selection index.
`void`
`setSelectionInterval(int index0, int index1)`
Changes the selection to be between `index0` and `index1` inclusive.
`void`
`setSelectionMode(int selectionMode)`
Sets the selection mode.
`void`
`setValueIsAdjusting(boolean valueIsAdjusting)`
Sets the `valueIsAdjusting` property, which indicates whether or not upcoming selection changes should be considered part of a single change.

## Field Details

### SINGLE_SELECTION

static final int SINGLE_SELECTION
A value for the selectionMode property: select one list index at a time.

See Also:
  - `setSelectionMode(int)`
  - Constant Field Values

### SINGLE_INTERVAL_SELECTION

static final int SINGLE_INTERVAL_SELECTION
A value for the selectionMode property: select one contiguous range of indices at a time.

See Also:
  - `setSelectionMode(int)`
  - Constant Field Values

### MULTIPLE_INTERVAL_SELECTION

static final int MULTIPLE_INTERVAL_SELECTION
A value for the selectionMode property: select one or more contiguous ranges of indices at a time.

See Also:
  - `setSelectionMode(int)`
  - Constant Field Values

## Method Details

### setSelectionInterval

void setSelectionInterval(int index0, int index1)
Changes the selection to be between `index0` and `index1` inclusive. `index0` doesn't have to be less than or equal to `index1`.

In `SINGLE_SELECTION` selection mode, only the second index is used.

If this represents a change to the current selection, then each `ListSelectionListener` is notified of the change.

Parameters:
  `index0` - one end of the interval.
  `index1` - other end of the interval
See Also:
  - `addListSelectionListener(ListSelectionListener)`

### addSelectionInterval

void addSelectionInterval(int index0, int index1)
Changes the selection to be the set union of the current selection and the indices between `index0` and `index1` inclusive. `index0` doesn't have to be less than or equal to `index1`.

In `SINGLE_SELECTION` selection mode, this is equivalent to calling `setSelectionInterval`, and only the second index is used. In `SINGLE_INTERVAL_SELECTION` selection mode, this method behaves like `setSelectionInterval`, unless the given interval is immediately adjacent to or overlaps the existing selection, and can therefore be used to grow the selection.

If this represents a change to the current selection, then each `ListSelectionListener` is notified of the change.

Parameters:
  `index0` - one end of the interval.
  `index1` - other end of the interval
See Also:
  - `addListSelectionListener(ListSelectionListener)`
  - `setSelectionInterval(int, int)`

### removeSelectionInterval

void removeSelectionInterval(int index0, int index1)
Changes the selection to be the set difference of the current selection and the indices between `index0` and `index1` inclusive. `index0` doesn't have to be less than or equal to `index1`.

In `SINGLE_INTERVAL_SELECTION` selection mode, if the removal would produce two disjoint selections, the removal is extended through the greater end of the selection. For example, if the selection is `0-10` and you supply indices `5,6` (in any order) the resulting selection is `0-4`.

If this represents a change to the current selection, then each `ListSelectionListener` is notified of the change.

Parameters:
  `index0` - one end of the interval.
  `index1` - other end of the interval
See Also:
  - `addListSelectionListener(ListSelectionListener)`

### getMinSelectionIndex

int getMinSelectionIndex()
Returns the first selected index or -1 if the selection is empty.

Returns:
  the first selected index or -1 if the selection is empty.

### getMaxSelectionIndex

int getMaxSelectionIndex()
Returns the last selected index or -1 if the selection is empty.

Returns:
  the last selected index or -1 if the selection is empty.

### isSelectedIndex

boolean isSelectedIndex(int index)
Returns true if the specified index is selected.

Parameters:
  `index` - an index
Returns:
  `true` if the specified index is selected

### getAnchorSelectionIndex

int getAnchorSelectionIndex()
Return the first index argument from the most recent call to setSelectionInterval(), addSelectionInterval() or removeSelectionInterval(). The most recent index0 is considered the "anchor" and the most recent index1 is considered the "lead". Some interfaces display these indices specially, e.g. Windows95 displays the lead index with a dotted yellow outline.

Returns:
  the anchor selection index
See Also:
  - `getLeadSelectionIndex()`
  - `setSelectionInterval(int, int)`
  - `addSelectionInterval(int, int)`

### setAnchorSelectionIndex

void setAnchorSelectionIndex(int index)
Set the anchor selection index.

Parameters:
  `index` - the anchor selection index
See Also:
  - `getAnchorSelectionIndex()`

### getLeadSelectionIndex

int getLeadSelectionIndex()
Return the second index argument from the most recent call to setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().

Returns:
  the lead selection index.
See Also:
  - `getAnchorSelectionIndex()`
  - `setSelectionInterval(int, int)`
  - `addSelectionInterval(int, int)`

### setLeadSelectionIndex

void setLeadSelectionIndex(int index)
Set the lead selection index.

Parameters:
  `index` - the lead selection index
See Also:
  - `getLeadSelectionIndex()`

### clearSelection

void clearSelection()
Change the selection to the empty set. If this represents a change to the current selection then notify each ListSelectionListener.

See Also:
  - `addListSelectionListener(ListSelectionListener)`

### isSelectionEmpty

boolean isSelectionEmpty()
Returns true if no indices are selected.

Returns:
  `true` if no indices are selected.

### insertIndexInterval

void insertIndexInterval(int index, int length, boolean before)
Insert `length` indices beginning before/after `index`. This is typically called to sync the selection model with a corresponding change in the data model.

Parameters:
  `index` - the beginning of the interval
  `length` - the length of the interval
  `before` - if `true`, interval inserts before the `index`, otherwise, interval inserts after the `index`

### removeIndexInterval

void removeIndexInterval(int index0, int index1)
Remove the indices in the interval `index0,index1` (inclusive) from the selection model. This is typically called to sync the selection model width a corresponding change in the data model.

Parameters:
  `index0` - the beginning of the interval
  `index1` - the end of the interval

### setValueIsAdjusting

void setValueIsAdjusting(boolean valueIsAdjusting)
Sets the `valueIsAdjusting` property, which indicates whether or not upcoming selection changes should be considered part of a single change. The value of this property is used to initialize the `valueIsAdjusting` property of the `ListSelectionEvent`s that are generated.

For example, if the selection is being updated in response to a user drag, this property can be set to `true` when the drag is initiated and set to `false` when the drag is finished. During the drag, listeners receive events with a `valueIsAdjusting` property set to `true`. At the end of the drag, when the change is finalized, listeners receive an event with the value set to `false`. Listeners can use this pattern if they wish to update only when a change has been finalized.

Setting this property to `true` begins a series of changes that is to be considered part of a single change. When the property is changed back to `false`, an event is sent out characterizing the entire selection change (if there was one), with the event's `valueIsAdjusting` property set to `false`.

Parameters:
  `valueIsAdjusting` - the new value of the property
See Also:
  - `getValueIsAdjusting()`
  - `ListSelectionEvent.getValueIsAdjusting()`

### getValueIsAdjusting

boolean getValueIsAdjusting()
Returns `true` if the selection is undergoing a series of changes.

Returns:
  true if the selection is undergoing a series of changes
See Also:
  - `setValueIsAdjusting(boolean)`

### setSelectionMode

void setSelectionMode(int selectionMode)
Sets the selection mode. The following list describes the accepted selection modes:

- `ListSelectionModel.SINGLE_SELECTION` - Only one list index can be selected at a time. In this mode, `setSelectionInterval` and `addSelectionInterval` are equivalent, both replacing the current selection with the index represented by the second argument (the "lead").
- `ListSelectionModel.SINGLE_INTERVAL_SELECTION` - Only one contiguous interval can be selected at a time. In this mode, `addSelectionInterval` behaves like `setSelectionInterval` (replacing the current selection), unless the given interval is immediately adjacent to or overlaps the existing selection, and can therefore be used to grow it.
- `ListSelectionModel.MULTIPLE_INTERVAL_SELECTION` - In this mode, there's no restriction on what can be selected.

Parameters:
  `selectionMode` - the selection mode
Throws:
  `IllegalArgumentException` - if the selection mode isn't one of those allowed
See Also:
  - `getSelectionMode()`

### getSelectionMode

int getSelectionMode()
Returns the current selection mode.

Returns:
  the current selection mode
See Also:
  - `setSelectionMode(int)`

### addListSelectionListener

void addListSelectionListener(ListSelectionListener x)
Add a listener to the list that's notified each time a change to the selection occurs.

Parameters:
  `x` - the ListSelectionListener
See Also:
  - `removeListSelectionListener(ListSelectionListener)`
  - `setSelectionInterval(int, int)`
  - `addSelectionInterval(int, int)`
  - `removeSelectionInterval(int, int)`
  - `clearSelection()`
  - `insertIndexInterval(int, int, boolean)`
  - `removeIndexInterval(int, int)`

### removeListSelectionListener

void removeListSelectionListener(ListSelectionListener x)
Remove a listener from the list that's notified each time a change to the selection occurs.

Parameters:
  `x` - the ListSelectionListener
See Also:
  - `addListSelectionListener(ListSelectionListener)`

### getSelectedIndices

default int[] getSelectedIndices()
Returns an array of all of the selected indices in the selection model, in increasing order.

Implementation Requirements:
  The default implementation iterates from minimum selected index `getMinSelectionIndex()` to maximum selected index `getMaxSelectionIndex()` and returns the selected indices `isSelectedIndex(int)` in a newly allocated int array.
Returns:
  all of the selected indices, in increasing order, or an empty array if nothing is selected
Since:
  11
See Also:
  - `removeSelectionInterval(int, int)`
  - `addListSelectionListener(ListSelectionListener)`

### getSelectedItemsCount

default int getSelectedItemsCount()
Returns the number of selected items.

Implementation Requirements:
  The default implementation iterates from minimum selected index `getMinSelectionIndex()` to maximum selected index `getMaxSelectionIndex()` and returns the number of selected indices `isSelectedIndex(int)`
Returns:
  the number of selected items, 0 if no items are selected
Since:
  11