Element Factories

Identifier:

org.eclipse.ui.elementFactories

Description:

This extension point is used to add element factories to the workbench. An element factory is used to recreate IAdaptable objects which are persisted during workbench shutdown.

As an example, the element factory is used to persist editor input. The input for an editor must implement org.eclipse.ui.EditorInput. The life cycle of an IEditorInput within an editor has a number of phases.

The initial input for an editor is passed in during editor creation.
On shutdown the workbench state is captured. In this process the workbench will create a memento for each open editor and its input. The input is saved as a two part memento containing a factory ID and any primitive data required to recreate the element on startup. For more information see the documentation on org.eclipse.ui.IPersistableElement.
On startup the workbench state is read and the editors from the previous session are recreated. In this process the workbench will recreate the input element for each open editor. To do this it will map the original factory ID for the input element to a concrete factory class defined in the registry. If a mapping exists, and the factory class is valid, an instance of the factory class is created. Then the workbench asks the factory to recreate the original element from the remaining primitive data within the memento. The resulting IAdaptable is cast to an IEditorInput and passed to the new editor.

Configuration Markup:

<!ELEMENT extension (factory*)>

<!ATTLIST extension

point CDATA #REQUIRED

id CDATA #IMPLIED

name CDATA #IMPLIED>

point - a fully qualified identifier of the target extension point
id - an optional identifier of the extension instance
name - an optional name of the extension instance

<!ELEMENT factory EMPTY>

<!ATTLIST factory

id CDATA #REQUIRED

class CDATA #REQUIRED>

id - a unique name that will be used to identify this factory.
class - a fully qualified name of a class that implements org.eclipse.ui.IElementFactory

Examples:

The following is an example of an element factory extension:


   <extension 
        point = "org.eclipse.ui.elementFactories"> 
        <factory 
           id ="com.xyz.ElementFactory" 
           class="com.xyz.ElementFactory"> 
        </factory> 
    </extension>

API Information:

The value of the class attribute must be a fully qualified name of a class that implements org.eclipse.ui.IElementFactory. An instance of this class must create an IAdaptable object from a workbench memento.

Supplied Implementation:

The workbench provides an IResource factory. Additional factories should be added to recreate other IAdaptable types commonly found in other object models, such as the Java Model.

Copyright (c) 2002, 2005 IBM Corporation and others.
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which accompanies this distribution, and is available at https://www.eclipse.org/legal/epl-v20.html/ SPDX-License-Identifier: EPL-2.0