EOActionAssociation

Inherits from:
EOActionWidgetAssociation : EOWidgetAssociation : EOAssociation : EODelayedObserver (EOControl) : Object

Implements:
NSDisposable
EOObserving (EOControl)

Package:
com.webobjects.eointerface

Class Description

An EOActionAssociation object allows you to set up an interface object, such as a button, to send a message to the objects selected in the association's display group when the interface object is acted on.

Usable With

com.webobjects.eointerface.swing: Any object that implements the method addActionListener (javax.swing.JButton and javax.swing.JMenuItem, for example). com.webobjects.eointerface.cocoa: NSControl, NSActionCell, and their subclasses.

Aspects
`action`	Bound to a key that names the method to invoke on the selected objects. If the `argument` aspect isn't bound, the method must take no arguments. If the `argument` aspect is bound, then the method must take exactly one argument.
`argument`	An object attribute or relationship of the selected object, passed as an argument to the action method. (Usually bound to a different EODisplayGroup than the one bound to `action`.)
`enabled`	A boolean attribute of the selected object, which determines whether the display object is enabled.

Object Keys Taken
`target`	On receiving an action message from the display object, an EOActionAssocation sends its action to the selected objects.

Examples

Suppose you have an application that manages member accounts, each of which has a restriction on the outstanding balance allowed. You want a user to be able to increase the restriction limit by selecting one or more members and then clicking a button. To do this, you define a boostRestrictions method in the Member class that increases the limit by 20%. In Interface Builder, control-drag a connection from the button to the Member display group. Select EOActionAssociation in the Connections inspector, and bind the association's action aspect to the "boostRestrictions" key.

In another scenario, one EODisplayGroup shows Members, while another shows video tapes available for rent. Here, you want a user to be able to select a member, select a video tape, and then click a Rent button that checks the selected tape out to the selected member. To do this, define a rentVideoTape method in the Member class that takes a VideoTape as an argument and handles the accounting involved in a video rental. Then, in Interface Builder, control-drag a connection from the button to the Members display group. Select EOActionAssociation in the Connections inspector, and bind the association's action aspect to Member's rentVideoTape action. Similarly, control-drag a connection from the button to the VideoTape display group. Select EOActionAssociation in the Connections inspector, and bind the association's argument aspect to the VideoTape display group. Now, when the user selects a Member, selects a VideoTape, and clicks the button, the selected Member is sent a rentVideoTape message with the selected VideoTape.

Interfaces Implemented

NSDisposable

EOObserving

Method Types

All methods

EOActionAssociation
displayGroupSelectionsAllowEnabled
invokeAction
primaryAspect

Constructors