NOTE: This section assumes you have a working knowledge of writing, compiling and deploying Java classes.

The Custom Message Handler is a Java class that allows you to extend the functionality of RTView by implementing code to update your system when the table is edited. Once the Custom Message Handler has been created, it can be deployed with your displays so that end users who are editing tables do not need to be familiar with the systems they are updating.

To implement a Custom Message Handler, you must create a Java class named MyMessageHandler.java that extends GmsRtViewCustomMessageHandler. NOTE: If you will be using the Custom Message Handler with the Display Viewer Applet, pack the Java class you create into one of the applet .jar files before deploying.

In MyMessageHandler.java define the following method:

public boolean invokeMessage (String messageString, Object value)

The invokeMessage method must return true when it receives any of the following messages, otherwise it must return false. NOTE: The MessageHandler will receive other messages, but the method should not return true or implement code when receiving anything other than the messages listed below.

The following lists messages and corresponding value arguments:

Message	Description	Object Array Values
table_edit_start	The invokeMessage method will get called with this message when Edit Table is selected from the popup menu.	Argument	Definition	Type
		value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of the variable assigned to editDataLocalVarName.	String
		value[2]	Initial table data prior to editing.	GmsTabularData
		value[3]	Null	Null
table_edit_save	The invokeMessage method will get called with this message when Save Edits is selected from the popup menu or when Yes is selected if prompted to save while exiting.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	Table data containing table edits.	GmsTabularData
		value[3]	Null	Null
table_edit_cancel	The invokeMessage method will get called with this message when Cancel Edits is selected from the popup menu or when No is selected if prompted to save while exiting.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	Table data containing the current value of valueTable. If data for the valueTable attachment was updated during editing, this may not be the same as data sent with the table_edit_start message. This message does not contain table edits.	GmsTabularData
		value[3]	Null	Null
table_edit_remove_row	This message is sent when Remove Row or Remove Rows is selected from the popup menu.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	GmsTabularData object with one or more data rows that were deleted.	GmsTabularData
		value[3]	Each entry is the index of a deleted row.	int[]
table_edit_insert_row	This message is sent when Insert Row is selected from the popup menu.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	GmsTabularData object with one row that contains the row data that was inserted.	GmsTabularData
		value[3]	Value is the index of the inserted row.	Integer
table_edit_update_row	This message is sent when a cell from the table is edited.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	GmsTabularData object with two rows. Row[0] contains row data before the cell was edited, Row[1] contains row data after the cell was edited.	GmsTabularData
		value[3]	Element[0] is the row number of the cell. Element[1] is the column number of the cell or the value -1 for the row label column.	int[]
table_edit_remove_column	This message is sent when Remove Column or Remove Columns is selected from the popup menu.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	GmsTabularData object with columns that existed before the column was removed and no rows.	GmsTabularData
		value[3]	Each entry is the index of a deleted column.	int[]
table_edit_insert_column	This message is sent when Insert Column is selected from the popup menu.	value[0]	Table object being edited.	GmsAppObject
		value[1]	Name of variable assigned to editDataLocalVarName.	String
		value[2]	GmsTabularData object with columns that existed after the column was inserted and no rows.	GmsTabularData
		value[3]	Value is the index of the inserted column.	Integer