FAQ What is a preference scope?
The preference service uses the notion of preference scopes to describe the various areas where preferences can be saved. The platform includes the following four preference scopes:
- Configuration scope. Preferences stored in this scope are shared
by all workspaces that are launched using a particular configuration of Eclipse plug-ins. On a single-user installation, this serves to capture preferences that are common to all workspaces launched by that user. On a multi-user installation, these preferences are shared by all users of the configuration.</li>
- Instance scope. Preferences in this scope are specific
to a single Eclipse workspace. The old API method getPluginPreferences on Plugin stores its preferences at this scope.</li>
- Default scope. This scope is not stored on disk at all but can be used
to store default values for all your keys. When values are not found in other scopes, the default scope is consulted last to provide reasonable default values.</li>
- Project scope. This scope
stores values that are specific to a single project in your workspace, such as code formatter and compiler settings. Note that this scope is provided by the org.eclipse.core.resources plug-in, which is not included in the Eclipse Rich Client Platform. This scope will not exist in applications that dont explicitly include the resources plug-in.</li>
Plug-ins can also define their own preference scopes, using the org.eclipse.core.runtime.preference extension point. If you define your own scope, you can control how and where your preferences are loaded and stored. However, for most clients, the four built in scopes will be sufficient.
This FAQ was originally published in Official Eclipse 3.0 FAQs. Copyright 2004, Pearson Education, Inc. All rights reserved. This text is made available here under the terms of the Eclipse Public License v1.0.