Eclipse Plug-in Developer Guide (Galileo) - IContextService (Eclipse Platform API Specification)

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Eclipse Platform
Release 3.5

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org.eclipse.ui.contexts
Interface IContextService

All Superinterfaces:: IDisposable, IServiceWithSources

public interface IContextService
extends IServiceWithSources
extends IServiceWithSources

Provides services related to contexts in the Eclipse workbench. This provides access to contexts.

This service can be acquired from your service locator:

        IContextService service = (IContextService) getSite().getService(IContextService.class);

This service is available globally.

Since:: 3.1
Restriction:: This interface is not intended to be implemented by clients.
Restriction:: This interface is not intended to be extended by clients.

Field Summary

static String CONTEXT_ID_DIALOG
          The identifier for the context that is active when a shell registered as a dialog.

static String CONTEXT_ID_DIALOG_AND_WINDOW
          The identifier for the context that is active when a shell is registered as either a window or a dialog.

static String CONTEXT_ID_WINDOW
          The identifier for the context that is active when a shell is registered as a window.

static int TYPE_DIALOG
          The type used for registration indicating that the shell should be treated as a dialog.

static int TYPE_NONE
          The type used for registration indicating that the shell should not receive any key bindings be default.

static int TYPE_WINDOW
          The type used for registration indicating that the shell should be treated as a window.

Method Summary

IContextActivation activateContext ( String contextId)
           Activates the given context within the context of this service.

IContextActivation activateContext ( String contextId, Expression expression)
           Activates the given context within the context of this service.

IContextActivation activateContext ( String contextId, Expression expression, boolean global)
           Activates the given context within the context of this service.

IContextActivation activateContext ( String contextId, Expression expression, int sourcePriorities)
          Deprecated. Use activateContext(String, Expression) instead.

void addContextManagerListener ( IContextManagerListener listener)
          Adds a listener to this context service.

void deactivateContext ( IContextActivation activation)
          Deactivates the given context within the context of this service.

void deactivateContexts ( Collection activations)
          Deactivates the given contexts within the context of this service.

void deferUpdates (boolean defer)
          Informs the service that a batch operation has started.

Collection getActiveContextIds ()
          Returns the set of active context identifiers.

Context getContext ( String contextId)
          Retrieves the context with the given identifier.

Collection getDefinedContextIds ()
          Returns the collection of the identifiers for all of the defined contexts in the workbench.

Context[] getDefinedContexts ()
          Returns the collection of all of the defined contexts in the workbench.

int getShellType ( Shell shell)
          Returns the shell type for the given shell.

void readRegistry ()
           Reads the context information from the registry and the preferences.

boolean registerShell ( Shell shell, int type)
           Registers a shell to automatically promote or demote some basic types of contexts.

void removeContextManagerListener ( IContextManagerListener listener)
          Removes a listener from this context service.

boolean unregisterShell ( Shell shell)
           Unregisters a shell that was previously registered.

Methods inherited from interface org.eclipse.ui.services. IServiceWithSources

addSourceProvider, removeSourceProvider

Methods inherited from interface org.eclipse.ui.services. IDisposable

dispose

Field Detail

CONTEXT_ID_DIALOG

static final 
String CONTEXT_ID_DIALOG

The identifier for the context that is active when a shell registered as a dialog.

See Also:: Constant Field Values

CONTEXT_ID_DIALOG_AND_WINDOW

static final 
String CONTEXT_ID_DIALOG_AND_WINDOW

The identifier for the context that is active when a shell is registered as either a window or a dialog.

See Also:: Constant Field Values

CONTEXT_ID_WINDOW

static final 
String CONTEXT_ID_WINDOW

The identifier for the context that is active when a shell is registered as a window.

See Also:: Constant Field Values

TYPE_DIALOG

static final int TYPE_DIALOG

The type used for registration indicating that the shell should be treated as a dialog. When the given shell is active, the "In Dialogs" context should also be active.

See Also:: Constant Field Values

TYPE_NONE

static final int TYPE_NONE

The type used for registration indicating that the shell should not receive any key bindings be default. When the given shell is active, we should not provide any EnabledSubmission instances for the "In Dialogs" or "In Windows" contexts.

See Also:: Constant Field Values

TYPE_WINDOW

static final int TYPE_WINDOW

The type used for registration indicating that the shell should be treated as a window. When the given shell is active, the "In Windows" context should also be active.

See Also:: Constant Field Values

Method Detail

activateContext


IContextActivation activateContext(
String contextId)

Activates the given context within the context of this service. If this service was retrieved from the workbench, then this context will be active globally. If the service was retrieved from a nested component, then the context will only be active within that component.

Also, it is guaranteed that the contexts submitted through a particular service will be cleaned up when that services is destroyed. So, for example, a service retrieved from a IWorkbenchPartSite would deactivate all of its contexts when the site is destroyed.

Parameters:: contextId - The identifier for the context which should be activated; must not be null.
Returns:: A token which can be used to later cancel the activation. Only someone with access to this token can cancel the activation. The activation will automatically be cancelled if the context from which this service was retrieved is destroyed.

activateContext


IContextActivation activateContext(
String contextId,
                                   
Expression expression)

Activates the given context within the context of this service. The context becomes active when expression evaluates to true. This is the same as calling activateContext(String, Expression, boolean) with global==false.

Also, it is guaranteed that the context submitted through a particular service will be cleaned up when that services is destroyed. So, for example, a service retrieved from a IWorkbenchPartSite would deactivate all of its handlers when the site is destroyed.

Parameters:: contextId - The identifier for the context which should be activated; must not be null.; expression - This expression must evaluate to true before this context will really become active. The expression may be null if the context should always be active.
Returns:: A token which can be used to later cancel the activation. Only someone with access to this token can cancel the activation. The activation will automatically be cancelled if the context from which this service was retrieved is destroyed.
Since:: 3.2
See Also:: ISources

activateContext


IContextActivation activateContext(
String contextId,
                                   
Expression expression,
                                   boolean global)

Activates the given context within the context of this service. The context becomes active when expression evaluates to true. If global==false then this service must also be the active service to activate the context.

Parameters:: contextId - The identifier for the context which should be activated; must not be null.; expression - This expression must evaluate to true before this context will really become active. The expression may be null if the context should always be active.; global - Indicates that the handler should be activated irrespectively of whether the corresponding workbench component (e.g., window, part, etc.) is active.
Returns:: A token which can be used to later cancel the activation. Only someone with access to this token can cancel the activation. The activation will automatically be cancelled if the context from which this service was retrieved is destroyed.
Since:: 3.2
See Also:: ISources

activateContext


IContextActivation activateContext(
String contextId,
                                   
Expression expression,
                                   int sourcePriorities)

Deprecated. Use activateContext(String, Expression) instead.

Activates the given context within the context of this service. The context becomes active when expression evaluates to true.

Parameters:: contextId - The identifier for the context which should be activated; must not be null.; expression - This expression must evaluate to true before this context will really become active. The expression may be null if the context should always be active.; sourcePriorities - The source priorities for the expression.
Returns:: A token which can be used to later cancel the activation. Only someone with access to this token can cancel the activation. The activation will automatically be cancelled if the context from which this service was retrieved is destroyed.
See Also:: ISources

addContextManagerListener

void addContextManagerListener(
IContextManagerListener listener)

Adds a listener to this context service. The listener will be notified when the set of defined contexts changes. This can be used to track the global appearance and disappearance of contexts.

Note: listeners should be removed when no longer necessary. If not, they will be removed when the IServiceLocator used to acquire this service is disposed.

Parameters:: listener - The listener to attach; must not be null.
Since:: 3.2
See Also:: removeContextManagerListener(IContextManagerListener)

deactivateContext

void deactivateContext(
IContextActivation activation)

Deactivates the given context within the context of this service. If the handler was context with a different service, then it must be deactivated from that service instead. It is only possible to retract a context activation with this method. That is, you must have the same IContextActivation used to activate the context.

Parameters:: activation - The token that was returned from a call to activateContext; must not be null.

deactivateContexts

void deactivateContexts(
Collection activations)

Deactivates the given contexts within the context of this service. If the contexts were activated with a different service, then they must be deactivated from that service instead. It is only possible to retract context activations with this method. That is, you must have the same IContextActivation instances used to activate the contexts.

Parameters:: activations - The tokens that were returned from a call to activateContext. This collection must only contain instances of IContextActivation. The collection must not be null.

getActiveContextIds


Collection getActiveContextIds()

Returns the set of active context identifiers.

Returns:: The set of active context identifiers; this value may be null if no active contexts have been set yet. If the set is not null, then it contains only instances of String.
Since:: 3.2

getContext


Context getContext(
String contextId)

Retrieves the context with the given identifier. If no such context exists, then an undefined context with the given id is created.

Parameters:: contextId - The identifier to find; must not be null.
Returns:: A context with the given identifier, either defined or undefined.

getDefinedContexts


Context[] getDefinedContexts()

Returns the collection of all of the defined contexts in the workbench.

Returns:: The collection of contexts (Context) that are defined; never null, but may be empty.
Since:: 3.2

getDefinedContextIds


Collection getDefinedContextIds()

Returns the collection of the identifiers for all of the defined contexts in the workbench.

Returns:: The collection of context identifiers (String) that are defined; never null, but may be empty.

getShellType

int getShellType(
Shell shell)

Returns the shell type for the given shell.

Parameters:: shell - The shell for which the type should be determined. If this value is null, then IContextService.TYPE_NONE is returned.
Returns:: IContextService.TYPE_WINDOW, IContextService.TYPE_DIALOG, or IContextService.TYPE_NONE.

readRegistry

void readRegistry()

Reads the context information from the registry and the preferences. This will overwrite any of the existing information in the context service. This method is intended to be called during start-up. When this method completes, this context service will reflect the current state of the registry and preference store.

registerShell

boolean registerShell(
Shell shell,
                      int type)

Registers a shell to automatically promote or demote some basic types of contexts. The "In Dialogs" and "In Windows" contexts are provided by the system. This a convenience method to ensure that these contexts are promoted when the given is shell is active.

If a shell is registered as a window, then the "In Windows" context is enabled when that shell is active. If a shell is registered as a dialog -- or is not registered, but has a parent shell -- then the "In Dialogs" context is enabled when that shell is active. If the shell is registered as none -- or is not registered, but has no parent shell -- then the neither of the contexts will be enabled (by us -- someone else can always enabled them).

If the provided shell has already been registered, then this method will change the registration.

Parameters:: shell - The shell to register for key bindings; must not be null.; type - The type of shell being registered. This value must be one of the constants given in this interface.
Returns:: true if the shell had already been registered (i.e., the registration has changed); false otherwise.

removeContextManagerListener

void removeContextManagerListener(
IContextManagerListener listener)

Removes a listener from this context service.

Parameters:: listener - The listener to be removed; must not be null.
Since:: 3.2

unregisterShell

boolean unregisterShell(
Shell shell)

Unregisters a shell that was previously registered. After this method completes, the shell will be treated as if it had never been registered at all. If you have registered a shell, you should ensure that this method is called when the shell is disposed. Otherwise, a potential memory leak will exist.

If the shell was never registered, or if the shell is null, then this method returns false and does nothing.

Parameters:: shell - The shell to be unregistered; does nothing if this value is null.
Returns:: true if the shell had been registered; false otherwise.

deferUpdates

void deferUpdates(boolean defer)

Informs the service that a batch operation has started.

Note: You must insure that if you call deferUpdates(true) that nothing in your batched operation will prevent the matching call to deferUpdates(false).

Parameters:: defer - true when starting a batch operation false when ending the operation
Since:: 3.5

Overview

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Help

Eclipse Platform
Release 3.5

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Guidelines for using Eclipse APIs.

org.eclipse.ui.contexts Interface IContextService

CONTEXT_ID_DIALOG

CONTEXT_ID_DIALOG_AND_WINDOW

CONTEXT_ID_WINDOW

TYPE_DIALOG

TYPE_NONE

TYPE_WINDOW

activateContext

activateContext

activateContext

activateContext

addContextManagerListener

deactivateContext

deactivateContexts

getActiveContextIds

getContext

getDefinedContexts

getDefinedContextIds

getShellType

readRegistry

registerShell

removeContextManagerListener

unregisterShell

deferUpdates

org.eclipse.ui.contexts
Interface IContextService