How to Write a Table Model Listener

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Trail: Creating a GUI with JFC/Swing
Lesson: Writing Event Listeners

How to Write a Table Model Listener

Each JTable object has a table model that holds its data. When a table model listener is registered on the table model, the listener is notified every time the table model's data changes. The JTable itself automatically uses a table model listener to make its GUI reflect the current state of the table model. You register a table model listener using the TableModel addTableModelListener method.

The Table Model Listener API

The TableModelListener Interface
Because TableModelListener has only one method, it has no corresponding adapter class.

Method Purpose

tableChanged(TableModelEvent) Called when the structure of or data in the table has changed.

The TableModelEvent API

Method Purpose

Object getSource()
(in java.util.EventObject) Return the object that fired the event.

int getFirstRow() Return the index of the first row that changed. TableModelEvent.HEADER_ROW specifies the table header.

int getLastRow() The last row that changed. Again, HEADER_ROW is a possible value.

int getColumn() Return the index of the column that changed. The constant TableModelEvent.ALL_COLUMNS specifies that all the columns might have changed.

int getType() What happened to the changed cells. The returned value is one of the following: TableModelEvent.INSERT, TableModelEvent.DELETE, or TableModelEvent.UPDATE.

Method	Purpose
`tableChanged(TableModelEvent)`	Called when the structure of or data in the table has changed.

Method	Purpose
`Object getSource()` (in `java.util.EventObject`)	Return the object that fired the event.
`int getFirstRow()`	Return the index of the first row that changed. `TableModelEvent.HEADER_ROW` specifies the table header.
`int getLastRow()`	The last row that changed. Again, `HEADER_ROW` is a possible value.
`int getColumn()`	Return the index of the column that changed. The constant `TableModelEvent.ALL_COLUMNS` specifies that all the columns might have changed.
`int getType()`	What happened to the changed cells. The returned value is one of the following: `TableModelEvent.INSERT`, `TableModelEvent.DELETE`, or `TableModelEvent.UPDATE`.

Examples that Use Table Model Listeners

The following table lists the examples that use table model listeners.

Example Where Described Notes

TableMap Sorting and Otherwise Manipulating Data A superclass for data-manipulating table models. It implements a table model that sits between a table data model and a JTable. The TableMap listens for table model events from the data model, and then simply forwards them to its table model listeners (such as the JTable).

TableSorter Sorting and Otherwise Manipulating Data A sorting table model implemented as a subclass of TableMap. In addition to forwarding table model events, the tableChanged method keeps track of the number of rows.

SharedModelDemo — Does not implement a table model listener. Instead, it implements a combined list and table model.

Example	Where Described	Notes
`TableMap`	Sorting and Otherwise Manipulating Data	A superclass for data-manipulating table models. It implements a table model that sits between a table data model and a `JTable`. The `TableMap` listens for table model events from the data model, and then simply forwards them to its table model listeners (such as the `JTable`).
`TableSorter`	Sorting and Otherwise Manipulating Data	A sorting table model implemented as a subclass of `TableMap`. In addition to forwarding table model events, the `tableChanged` method keeps track of the number of rows.
`SharedModelDemo`	—	Does not implement a table model listener. Instead, it implements a combined list and table model.

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