E
- the type of the list elements and the selectionpublic final class SelectionInList<E> extends IndirectListModel<E> implements ValueModel
The SelectionInList uses three ValueModels to hold the list, the selection and selection index and provides bound bean properties for these models. You can access, observe and replace these ValueModels. This is useful to connect a SelectionInList with other ValueModels; for example you can use the SelectionInList's selection holder as bean channel for a PresentationModel. Since the SelectionInList is a ValueModel, it is often used as bean channel. See the Binding tutorial classes for examples on how to connect a SelectionInList with a PresentationModel.
This class also implements the ListModel
interface that allows
API users to observe fine grained changes in the structure and contents
of the list. Hence instances of this class can be used directly as model of
a JList. If you want to use a SelectionInList with a JComboBox or JTable,
you can convert the SelectionInList to the associated component model
interfaces using the adapter classes
ComboBoxAdapter
and AbstractTableAdapter
respectively.
These classes are part of the Binding library too.
The SelectionInList supports two list types as content of its list holder:
List
and ListModel
. The two modes differ in how
precise this class can fire events about changes to the content and structure
of the list. If you use a List, this class can only report
that the list changes completely; this is done by firing
a PropertyChangeEvent for the list property.
Also, a ListDataEvent
is fired that reports a complete change.
In contrast, if you use a ListModel it will report the same
PropertyChangeEvent. But fine grained changes in the list
model will be fired by this class to notify observes about changes in
the content, added and removed elements.
If the list content doesn't change at all, or if it always changes completely, you can work well with both List content and ListModel content. But if the list structure or content changes, the ListModel reports more fine grained events to registered ListDataListeners, which in turn allows list views to chooser better user interface gestures: for example, a table with scroll pane may retain the current selection and scroll offset.
An example for using a ListModel in a SelectionInList is the asynchronous transport of list elements from a server to a client. Let's say you transport the list elements in portions of 10 elements to improve the application's responsiveness. The user can then select and work with the SelectionInList as soon as the ListModel gets populated. If at a later time more elements are added to the list model, the SelectionInList can retain the selection index (and selection) and will just report a ListDataEvent about the interval added. JList, JTable and JComboBox will then just add the new elements at the end of the list presentation.
If you want to combine List operations and the ListModel change reports,
you may consider using an implementation that combines these two interfaces,
for example com.jgoodies.common.collect.ArrayListModel
or com.jgoodies.common.collect.LinkedListModel
.
Important Note: If you change the ListModel instance,
either by calling #setListModel(ListModel)
or by setting
a new value to the underlying list holder, you must ensure that
the list holder throws a PropertyChangeEvent whenever the instance changes.
This event is used to remove a ListDataListener from the old ListModel
instance and is later used to add it to the new ListModel instance.
It is easy to violate this constraint, just because Java's standard
PropertyChangeSupport helper class that is used by many beans, checks
a changed property value via #equals
, not ==
.
For example, if you change the SelectionInList's list model from an empty
list L1
to another empty list instance L2
,
the PropertyChangeSupport won't generate a PropertyChangeEvent,
and so, the SelectionInList won't know about the change, which
may lead to unexpected behavior.
This binding library provides some help for firing PropertyChangeEvents
if the old ListModel and new ListModel are equal but not the same.
Class ExtendedPropertyChangeSupport
allows to permanently or individually check the identity (using
==
) instead of checking the equity (using #equals
).
Class Model
uses this extended
property change support. And class ValueHolder
uses it too
and can be configured to always test the identity.
Since version 1.0.2 this class provides public convenience methods
for firing ListDataEvents, see the methods #fireContentsChanged
,
#fireIntervalAdded
, and #fireIntervalRemoved
.
These are automatically invoked if the list holder holds a ListModel
that fires these events. If on the other hand the underlying List or
ListModel does not fire a required ListDataEvent, you can use these
methods to notify presentations about a change. It is recommended
to avoid sending duplicate ListDataEvents; hence check if the underlying
ListModel fires the necessary events or not. Typically an underlying
ListModel will fire the add and remove events; but often it'll lack
an event if the (selected) contents has changed. A convenient way to
indicate that change is #fireSelectedContentsChanged
. See
the tutorial's AlbumManagerModel for an example how to use this feature.
The SelectionInList is partially defined for Lists and ListModels
that contain null
. Setting the selection to null
on a SelectionInList that contains null
won't set the selection index
to the index of the first null
element. For details see the
setSelection(Object)
JavaDocs. This is because the current
implementation interprets a null
selection as unspecified,
which maps better to a cleared selection than to a concrete selection index.
Anyway, as long as you work with the selection index and selection index
holder, such a SelectionInList will work fine. This is the case if you bind
a SelectionInList to a JList or JTable. Binding such a SelectionInList
to a JComboBox won't synchronize the selection index if null
is selected.
Constraints: The list holder holds instances of List
or ListModel
, the selection holder values of type E
and the selection index holder of type Integer
. The selection
index holder must hold non-null index values; however, when firing
an index value change event, both the old and new value may be null.
If the ListModel changes, the underlying ValueModel must fire
a PropertyChangeEvent.
ValueModel
,
List
,
ListModel
,
ComboBoxAdapter
,
AbstractTableAdapter
,
ExtendedPropertyChangeSupport
,
Model
,
ValueHolder
Modifier and Type | Field and Description |
---|---|
static java.lang.String |
PROPERTYNAME_SELECTION
The name of the bound read-write selection property.
|
static java.lang.String |
PROPERTYNAME_SELECTION_EMPTY
The name of the bound read-only selectionEmpty property.
|
static java.lang.String |
PROPERTYNAME_SELECTION_HOLDER
The name of the bound read-write selection holder property.
|
static java.lang.String |
PROPERTYNAME_SELECTION_INDEX
The name of the bound read-write selectionIndex property.
|
static java.lang.String |
PROPERTYNAME_SELECTION_INDEX_HOLDER
The name of the bound read-write selection index holder property.
|
static java.lang.String |
PROPERTYNAME_VALUE
The name of the bound read-write value property.
|
PROPERTYNAME_LIST, PROPERTYNAME_LIST_HOLDER
Constructor and Description |
---|
SelectionInList()
Constructs a SelectionInList with an empty initial
ArrayListModel using defaults for the selection holder
and selection index holder. |
SelectionInList(E[] listItems)
Constructs a SelectionInList on the given item array
using defaults for the selection holder and selection index holder.
|
SelectionInList(E[] listItems,
ValueModel selectionHolder)
Constructs a SelectionInList on the given item array and
selection holder using a default selection index holder.
|
SelectionInList(E[] listItems,
ValueModel selectionHolder,
ValueModel selectionIndexHolder)
Constructs a SelectionInList on the given item array and
selection holder using a default selection index holder.
|
SelectionInList(java.util.List<E> list)
Constructs a SelectionInList on the given list
using defaults for the selection holder and selection index holder.
|
SelectionInList(java.util.List<E> list,
ValueModel selectionHolder)
Constructs a SelectionInList on the given list and
selection holder using a default selection index holder.
|
SelectionInList(java.util.List<E> list,
ValueModel selectionHolder,
ValueModel selectionIndexHolder)
Constructs a SelectionInList on the given list,
selection holder, and selection index holder.
|
SelectionInList(javax.swing.ListModel listModel)
Constructs a SelectionInList on the given list model
using defaults for the selection holder and selection index holder.
|
SelectionInList(javax.swing.ListModel listModel,
ValueModel selectionHolder)
Constructs a SelectionInList on the given list model
and selection holder using a default selection index holder.
|
SelectionInList(javax.swing.ListModel listModel,
ValueModel selectionHolder,
ValueModel selectionIndexHolder)
Constructs a SelectionInList on the given list model,
selection holder, and selection index holder.
|
SelectionInList(ValueModel listHolder)
Constructs a SelectionInList on the given list holder
using defaults for the selection holder and selection index holder.
|
SelectionInList(ValueModel listHolder,
ValueModel selectionHolder)
Constructs a SelectionInList on the given list holder,
selection holder and selection index holder.
|
SelectionInList(ValueModel listHolder,
ValueModel selectionHolder,
ValueModel selectionIndexHolder)
Constructs a SelectionInList on the given list holder,
selection holder and selection index holder.
|
Modifier and Type | Method and Description |
---|---|
void |
addValueChangeListener(java.beans.PropertyChangeListener l)
Registers the given PropertyChangeListener with this model.
|
void |
clearSelection()
Clears the selection of this SelectionInList - if any.
|
protected javax.swing.event.ListDataListener |
createListDataChangeHandler()
Creates and returns the ListDataListener used to observe
changes in the underlying ListModel.
|
void |
fireSelectedContentsChanged()
Notifies all registered ListDataListeners that the contents
of the selected list item - if any - has changed.
|
E |
getSelection()
Looks up and returns the current selection using
the current selection index.
|
ValueModel |
getSelectionHolder()
Returns the selection holder.
|
int |
getSelectionIndex()
Returns the selection index.
|
ValueModel |
getSelectionIndexHolder()
Returns the selection index holder.
|
E |
getValue()
Returns the current selection,
null if the selection index
does not represent a selection in the list. |
boolean |
hasSelection()
Checks and answers if an element is selected.
|
boolean |
isSelectionEmpty()
Checks and answers whether the selection is empty or not.
|
void |
release()
Removes the internal listeners from the list holder, selection holder,
selection index holder.
|
void |
removeValueChangeListener(java.beans.PropertyChangeListener l)
Removes the given PropertyChangeListener from the model.
|
void |
setSelection(E newSelection)
Sets the selection index to the index of the first list element
that equals
newSelection . |
void |
setSelectionHolder(ValueModel newSelectionHolder)
Sets a new selection holder.
|
void |
setSelectionIndex(int newSelectionIndex)
Sets a new selection index.
|
void |
setSelectionIndexHolder(ValueModel newSelectionIndexHolder)
Sets a new selection index holder.
|
void |
setValue(java.lang.Object newValue)
Sets the selection index to the index of the first list element
that equals
newValue . |
protected void |
updateList(java.lang.Object oldList,
int oldSize,
java.lang.Object newList)
Removes the list data change handler from the old list in case
it is a
ListModel and adds it to new one in case
it is a ListModel . |
addListDataListener, fireContentsChanged, fireIntervalAdded, fireIntervalRemoved, fireListChanged, getElementAt, getList, getListDataListeners, getListHolder, getListModel, getSize, getSize, isEmpty, removeListDataListener, setList, setListHolder, setListModel
createPropertyChangeSupport, firePropertyChange
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
addPropertyChangeListener, removePropertyChangeListener
public static final java.lang.String PROPERTYNAME_SELECTION
public static final java.lang.String PROPERTYNAME_SELECTION_EMPTY
public static final java.lang.String PROPERTYNAME_SELECTION_HOLDER
public static final java.lang.String PROPERTYNAME_SELECTION_INDEX
public static final java.lang.String PROPERTYNAME_SELECTION_INDEX_HOLDER
public static final java.lang.String PROPERTYNAME_VALUE
public SelectionInList()
ArrayListModel
using defaults for the selection holder
and selection index holder.public SelectionInList(E[] listItems)
Changes to the list "write through" to the array, and changes to the array contents will be reflected in the list.
listItems
- the array of initial itemsjava.lang.NullPointerException
- if listItems
is null
public SelectionInList(E[] listItems, ValueModel selectionHolder)
Changes to the list "write through" to the array, and changes to the array contents will be reflected in the list.
listItems
- the array of initial itemsselectionHolder
- holds the selectionjava.lang.NullPointerException
- if listItems
or
selectionHolder
is null
public SelectionInList(E[] listItems, ValueModel selectionHolder, ValueModel selectionIndexHolder)
Changes to the list "write through" to the array, and changes to the array contents will be reflected in the list.
listItems
- the array of initial itemsselectionHolder
- holds the selectionselectionIndexHolder
- holds the selection indexjava.lang.NullPointerException
- if listItems
,
selectionHolder
, or selectionIndexHolder
is null
public SelectionInList(java.util.List<E> list)
Note: Favor ListModel
over
List
when working with the SelectionInList.
Why? The SelectionInList can work with both types. What's the
difference? ListModel provides all list access features
required by the SelectionInList's. In addition it reports more
fine grained change events, instances of ListDataEvents
.
In contrast developer often create Lists and operate on them
and the ListModel may be inconvenient for these operations.
A convenient solution for this situation is to use the
ArrayListModel
and LinkedListModel
classes.
These implement both List and ListModel, offer the standard List
operations and report the fine grained ListDataEvents.
list
- the initial listpublic SelectionInList(java.util.List<E> list, ValueModel selectionHolder)
Note: Favor ListModel
over
List
when working with the SelectionInList.
Why? The SelectionInList can work with both types. What's the
difference? ListModel provides all list access features
required by the SelectionInList's. In addition it reports more
fine grained change events, instances of ListDataEvents
.
In contrast developer often create Lists and operate on them
and the ListModel may be inconvenient for these operations.
A convenient solution for this situation is to use the
ArrayListModel
and LinkedListModel
classes.
These implement both List and ListModel, offer the standard List
operations and report the fine grained ListDataEvents.
list
- the initial listselectionHolder
- holds the selectionjava.lang.NullPointerException
- if selectionHolder
is null
public SelectionInList(java.util.List<E> list, ValueModel selectionHolder, ValueModel selectionIndexHolder)
Note: Favor ListModel
over
List
when working with the SelectionInList.
Why? The SelectionInList can work with both types. What's the
difference? ListModel provides all list access features
required by the SelectionInList's. In addition it reports more
fine grained change events, instances of ListDataEvents
.
In contrast developer often create Lists and operate on them
and the ListModel may be inconvenient for these operations.
A convenient solution for this situation is to use the
ArrayListModel
and LinkedListModel
classes.
These implement both List and ListModel, offer the standard List
operations and report the fine grained ListDataEvents.
list
- the initial listselectionHolder
- holds the selectionselectionIndexHolder
- holds the selection indexjava.lang.NullPointerException
- if selectionHolder
,
or selectionIndexHolder
is null
public SelectionInList(javax.swing.ListModel listModel)
listModel
- the initial list modelpublic SelectionInList(javax.swing.ListModel listModel, ValueModel selectionHolder)
listModel
- the initial list modelselectionHolder
- holds the selectionjava.lang.NullPointerException
- if selectionHolder
is null
public SelectionInList(javax.swing.ListModel listModel, ValueModel selectionHolder, ValueModel selectionIndexHolder)
listModel
- the initial list modelselectionHolder
- holds the selectionselectionIndexHolder
- holds the selection indexjava.lang.NullPointerException
- if selectionHolder
,
or selectionIndexHolder
is null
public SelectionInList(ValueModel listHolder)
Constraints:
1) The listHolder must hold instances of List or ListModel and
2) must report a value change whenever the value's identity changes.
Note that many bean properties don't fire a PropertyChangeEvent
if the old and new value are equal - and so would break this constraint.
If you provide a ValueHolder, enable its identityCheck feature
during construction. If you provide an adapted bean property from
a bean that extends the JGoodies Model
class,
you can enable the identity check feature in the methods
#firePropertyChange
by setting the trailing boolean
parameter to true
.
listHolder
- holds the list or list modeljava.lang.NullPointerException
- if listHolder
is null
public SelectionInList(ValueModel listHolder, ValueModel selectionHolder)
Constraints:
1) The listHolder must hold instances of List or ListModel and
2) must report a value change whenever the value's identity changes.
Note that many bean properties don't fire a PropertyChangeEvent
if the old and new value are equal - and so would break this constraint.
If you provide a ValueHolder, enable its identityCheck feature
during construction. If you provide an adapted bean property from
a bean that extends the JGoodies Model
class,
you can enable the identity check feature in the methods
#firePropertyChange
by setting the trailing boolean
parameter to true
.
listHolder
- holds the list or list modelselectionHolder
- holds the selectionjava.lang.NullPointerException
- if listHolder
or selectionHolder
is null
public SelectionInList(ValueModel listHolder, ValueModel selectionHolder, ValueModel selectionIndexHolder)
Constraints:
1) The listHolder must hold instances of List or ListModel and
2) must report a value change whenever the value's identity changes.
Note that many bean properties don't fire a PropertyChangeEvent
if the old and new value are equal - and so would break this constraint.
If you provide a ValueHolder, enable its identityCheck feature
during construction. If you provide an adapted bean property from
a bean that extends the JGoodies Model
class,
you can enable the identity check feature in the methods
#firePropertyChange
by setting the trailing boolean
parameter to true
.
listHolder
- holds the list or list modelselectionHolder
- holds the selectionselectionIndexHolder
- holds the selection indexjava.lang.NullPointerException
- if the listModelHolder
,
selectionHolder
, or selectionIndexHolder
is null
java.lang.IllegalArgumentException
- if the listHolder is a ValueHolder
that doesn't check the identity when changing its valuejava.lang.ClassCastException
- if the listModelHolder contents
is neither a List nor a ListModelpublic void fireSelectedContentsChanged()
If the list holder holds a ListModel, this SelectionInList listens
to ListDataEvents fired by that ListModel, and forwards these events
by invoking the associated #fireXXX
method, which in turn
notifies all registered ListDataListeners. Therefore if you fire
ListDataEvents in an underlying ListModel, you don't need this method
and should not use it to avoid sending duplicate ListDataEvents.
ListModel
,
ListDataListener
,
ListDataEvent
public E getSelection()
null
if
no object is selected or if the list has no elements.null
if none is selectedpublic void setSelection(E newSelection)
newSelection
. If newSelection
is null
, it is interpreted as unspecified
and the selection index is set to -1, and this SelectionInList
has no selection. Does nothing if the list is empty or null
.newSelection
- the object to be set as new selection,
or null
to set the selection index to -1public boolean hasSelection()
public boolean isSelectionEmpty()
clearSelection()
,
hasSelection()
public void clearSelection()
public int getSelectionIndex()
java.lang.NullPointerException
- if the selection index holder
has a null Object setpublic void setSelectionIndex(int newSelectionIndex)
newSelectionIndex
- the selection index to be setjava.lang.IndexOutOfBoundsException
- if the new selection index
is outside the bounds of the listpublic ValueModel getSelectionHolder()
public void setSelectionHolder(ValueModel newSelectionHolder)
newSelectionHolder
- the selection holder to setjava.lang.NullPointerException
- if the new selection holder is nullpublic ValueModel getSelectionIndexHolder()
public void setSelectionIndexHolder(ValueModel newSelectionIndexHolder)
newSelectionIndexHolder
- the selection index holder to setjava.lang.NullPointerException
- if the new selection index holder is nulljava.lang.IllegalArgumentException
- if the value of the new selection index
holder is nullpublic E getValue()
null
if the selection index
does not represent a selection in the list.getValue
in interface ValueModel
public void setValue(java.lang.Object newValue)
newValue
. If newValue
is null
, it is interpreted as unspecified
and the selection index is set to -1, and this SelectionInList
has no selection. Does nothing if the list is empty or null
.setValue
in interface ValueModel
newValue
- the object to be set as new selection,
or null
to set the selection index to -1public void addValueChangeListener(java.beans.PropertyChangeListener l)
The PropertyChangeEvents delivered to the listener have the name set to "value". In other words, the listeners won't get notified when a PropertyChangeEvent is fired that has a null object as the name to indicate an arbitrary set of the event source's properties have changed.
In the rare case, where you want to notify a PropertyChangeListener even with PropertyChangeEvents that have no property name set, you can register the listener with #addPropertyChangeListener, not #addValueChangeListener.
addValueChangeListener
in interface ValueModel
l
- the listener to addValueModel
public void removeValueChangeListener(java.beans.PropertyChangeListener l)
removeValueChangeListener
in interface ValueModel
l
- the listener to removepublic void release()
#release
.To avoid memory leaks it is recommended to invoke this method, if the list holder, selection holder, or selection index holder live much longer than this SelectionInList. Instead of releasing the SelectionInList, you typically make the list holder, selection holder, and selection index holder obsolete by releasing the PresentationModel or BeanAdapter that has created them before.
As an alternative you may use ValueModels that in turn use
event listener lists implemented using WeakReference
.
Basically this release method performs the reverse operation performed during the SelectionInList construction.
release
in class IndirectListModel<E>
PresentationModel.release()
,
BeanAdapter.release()
,
WeakReference
protected javax.swing.event.ListDataListener createListDataChangeHandler()
#updateListModel
.createListDataChangeHandler
in class IndirectListModel<E>
protected void updateList(java.lang.Object oldList, int oldSize, java.lang.Object newList)
ListModel
and adds it to new one in case
it is a ListModel
.
It then fires a property change for the list and a contents change event
for the list content. Finally it tries to restore the previous selection
- if any.Since version 1.1 the selection will be restored after the list content change has been indicated. This is because some listeners may clear the selection in a side-effect. For example a JTable that is bound to this SelectionInList via an AbstractTableAdapter and a SingleSelectionAdapter will clear the selection if the new list has a size other than the old list.
updateList
in class IndirectListModel<E>
oldList
- the old list contentoldSize
- the size of the old List contentnewList
- the new list contentJTable.tableChanged(javax.swing.event.TableModelEvent)
Copyright © 2002-2010 JGoodies Karsten Lentzsch. All Rights Reserved.