# 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.

1. The initial input for an editor is passed in during editor creation.
2. 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`.
3. 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.
All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html