FileDocCategorySizeDatePackage
RowSorter.javaAPI DocJava SE 6 API15597Tue Jun 10 00:26:40 BST 2008javax.swing

RowSorter

public abstract class RowSorter extends Object
RowSorter provides the basis for sorting and filtering. Beyond creating and installing a RowSorter, you very rarely need to interact with one directly. Refer to {@link javax.swing.table.TableRowSorter TableRowSorter} for a concrete implementation of RowSorter for JTable.

RowSorter's primary role is to provide a mapping between two coordinate systems: that of the view (for example a JTable) and that of the underlying data source, typically a model.

The view invokes the following methods on the RowSorter:

  • toggleSortOrder — The view invokes this when the appropriate user gesture has occurred to trigger a sort. For example, the user clicked a column header in a table.
  • One of the model change methods — The view invokes a model change method when the underlying model has changed. There may be order dependencies in how the events are delivered, so a RowSorter should not update its mapping until one of these methods is invoked.
Because the view makes extensive use of the convertRowIndexToModel, convertRowIndexToView and getViewRowCount methods, these methods need to be fast.

RowSorter provides notification of changes by way of RowSorterListener. Two types of notification are sent:

  • RowSorterEvent.Type.SORT_ORDER_CHANGED — notifies listeners that the sort order has changed. This is typically followed by a notification that the sort has changed.
  • RowSorterEvent.Type.SORTED — notifies listeners that the mapping maintained by the RowSorter has changed in some way.
RowSorter implementations typically don't have a one-to-one mapping with the underlying model, but they can. For example, if a database does the sorting, toggleSortOrder might call through to the database (on a background thread), and override the mapping methods to return the argument that is passed in.

Concrete implementations of RowSorter need to reference a model such as TableModel or ListModel. The view classes, such as JTable and JList, will also have a reference to the model. To avoid ordering dependencies, RowSorter implementations should not install a listener on the model. Instead the view class will call into the RowSorter when the model changes. For example, if a row is updated in a TableModel JTable invokes rowsUpdated. When the model changes, the view may call into any of the following methods: modelStructureChanged, allRowsChanged, rowsInserted, rowsDeleted and rowsUpdated.

param
the type of the underlying model
version
1.7 06/23/06
see
javax.swing.table.TableRowSorter
since
1.6

Fields Summary
private EventListenerList
listenerList
Constructors Summary
public RowSorter()
Creates a RowSorter.
Methods Summary
public voidaddRowSorterListener(javax.swing.event.RowSorterListener l)
Adds a RowSorterListener to receive notification about this RowSorter. If the same listener is added more than once it will receive multiple notifications. If l is null nothing is done.

param
l the RowSorterListener

	listenerList.add(RowSorterListener.class, l);
public abstract voidallRowsChanged()
Invoked when the contents of the underlying model have completely changed. The structure of the table is the same, only the contents have changed. This is typically sent when it is too expensive to characterize the change in terms of the other methods.

You normally do not call this method. This method is public to allow view classes to call it.

public abstract intconvertRowIndexToModel(int index)
Returns the location of index in terms of the
underlying model. That is, for the row index in
the coordinates of the view this returns the row index in terms
of the underlying model.
param
index the row index in terms of the underlying view
return
row index in terms of the view
throws
IndexOutOfBoundsException if index is outside the
range of the view
public abstract intconvertRowIndexToView(int index)
Returns the location of index in terms of the
view. That is, for the row index in the
coordinates of the underlying model this returns the row index
in terms of the view.
param
index the row index in terms of the underlying model
return
row index in terms of the view, or -1 if index has been
filtered out of the view
throws
IndexOutOfBoundsException if index is outside
the range of the model
protected voidfireRowSorterChanged(int[] lastRowIndexToModel)
Notifies listener that the mapping has changed.
param
lastRowIndexToModel the mapping from model indices to
view indices prior to the sort, may be null
        fireRowSorterChanged(new RowSorterEvent(this,
                RowSorterEvent.Type.SORTED, lastRowIndexToModel));
    
voidfireRowSorterChanged(javax.swing.event.RowSorterEvent event)
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length - 2; i >= 0; i -= 2) {
            if (listeners[i] == RowSorterListener.class) {
                ((RowSorterListener)listeners[i + 1]).
                        sorterChanged(event);
            }
        }
    
protected voidfireSortOrderChanged()
Notifies listener that the sort order has changed.
        fireRowSorterChanged(new RowSorterEvent(this));
    
public abstract MgetModel()
Returns the underlying model.
return
the underlying model
public abstract intgetModelRowCount()
Returns the number of rows in the underlying model.
return
number of rows in the underlying model
see
#getViewRowCount
public abstract java.util.ListgetSortKeys()
Returns the current sort keys. This must return a {@code
non-null List} and may return an unmodifiable {@code List}. If
you need to change the sort keys, make a copy of the returned
{@code List}, mutate the copy and invoke {@code setSortKeys}
with the new list.
return
the current sort order
public abstract intgetViewRowCount()
Returns the number of rows in the view. If the contents have
been filtered this might differ from the row count of the
underlying model.
return
number of rows in the view
see
#getModelRowCount
public abstract voidmodelStructureChanged()
Invoked when the underlying model structure has completely
changed. For example, if the number of columns in a
TableModel changed, this method would be invoked.


You normally do not call this method. This method is public
to allow view classes to call it.
public voidremoveRowSorterListener(javax.swing.event.RowSorterListener l)
Removes a RowSorterListener. If
l is null nothing is done.
param
l the RowSorterListener
	listenerList.remove(RowSorterListener.class, l);
    
public abstract voidrowsDeleted(int firstRow, int endRow)
Invoked when rows have been deleted from the underlying model
in the specified range (inclusive).


The arguments give the indices of the effected range and
are in terms of the model before the change.
For example, if you have a 5-row model and delete 3 items from the end
of the model the indices are 2, 4.


You normally do not call this method. This method is public
to allow view classes to call it.
param
firstRow the first row
param
endRow the last row
throws
IndexOutOfBoundsException if either argument is outside
the range of the model before the change, or
firstRow > endRow
public abstract voidrowsInserted(int firstRow, int endRow)
Invoked when rows have been inserted into the underlying model
in the specified range (inclusive).


The arguments give the indices of the effected range.
The first argument is in terms of the model before the change, and
must be less than or equal to the size of the model before the change.
The second argument is in terms of the model after the change and must
be less than the size of the model after the change. For example,
if you have a 5-row model and add 3 items to the end of the model
the indices are 5, 7.


You normally do not call this method. This method is public
to allow view classes to call it.
param
firstRow the first row
param
endRow the last row
throws
IndexOutOfBoundsException if either argument is invalid, or
firstRow > endRow
public abstract voidrowsUpdated(int firstRow, int endRow)
Invoked when rows have been changed in the underlying model
between the specified range (inclusive).


You normally do not call this method. This method is public
to allow view classes to call it.
param
firstRow the first row, in terms of the underlying model
param
endRow the last row, in terms of the underlying model
throws
IndexOutOfBoundsException if either argument is outside
the range of the underlying model, or
firstRow > endRow
public abstract voidrowsUpdated(int firstRow, int endRow, int column)
Invoked when the column in the rows have been updated in
the underlying model between the specified range.


You normally do not call this method. This method is public
to allow view classes to call it.
param
firstRow the first row, in terms of the underlying model
param
endRow the last row, in terms of the underlying model
param
column the column that has changed, in terms of the underlying
model
throws
IndexOutOfBoundsException if either argument is outside
the range of the underlying model after the change,
firstRow > endRow, or
column is outside the range of the underlying
model
public abstract voidsetSortKeys(java.util.List keys)
Sets the current sort keys.
param
keys the new SortKeys; null
is a shorthand for specifying an empty list,
indicating that the view should be unsorted
public abstract voidtoggleSortOrder(int column)
Reverses the sort order of the specified column. It is up to
subclasses to provide the exact behavior when invoked. Typically
this will reverse the sort order from ascending to descending (or
descending to ascending) if the specified column is already the
primary sorted column; otherwise, makes the specified column
the primary sorted column, with an ascending sort order. If
the specified column is not sortable, this method has no
effect.


If this results in changing the sort order and sorting, the
appropriate RowSorterListener notification will be
sent.
param
column the column to toggle the sort ordering of, in
terms of the underlying model
throws
IndexOutOfBoundsException if column is outside the range of
the underlying model