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

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Eclipse Platform
Release 3.5

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org.eclipse.help
Interface IContextProvider

public interface IContextProvider

Dynamic context provider. Classes that implement this interface should be returned from adaptable objects when IContextProvider.class is used as the adapter key. Adaptable objects must implement org.eclipse.core.runtime.IAdaptable interface.

Dynamic context providers should be used for providing focused dynamic help that changes depending on the various platform states. State change criteria is defined by bitwise-OR of the individual state change triggers. Each time a registered trigger occurs, the class that implements this interface will be called again to provide the help context for the given target.

Context provider should be used for all visual artifacts that provide context help that handle context help trigger by handling the SWT help event instead of tagging the artifact with a static context Id.

In addition to providing static help context, this interface can also be used to control the query string that is passed to the help search system on context switches. If not provided, the query string is computed based on the current context. Providing the string explicitly gives the context owners better control over the search outcome.

Since:: 3.1
See Also:: IContext, IAdaptable

Field Summary

static int NONE
          State change trigger indicating a static context provider.

static int SELECTION
          State change trigger indicating that the provider should be asked for context help on each selection change.

Method Summary

IContext getContext ( Object target)
          Returns a help context for the given target.

int getContextChangeMask ()
          Returns the mask created by combining supported change triggers using the bitwise OR operation.

String getSearchExpression ( Object target)
          Returns a search expression that should be used to find more information about the current target.

Field Detail

NONE

static final int NONE

State change trigger indicating a static context provider.

See Also:: Constant Field Values

SELECTION

static final int SELECTION

State change trigger indicating that the provider should be asked for context help on each selection change.

See Also:: Constant Field Values

Method Detail

getContextChangeMask

int getContextChangeMask()

Returns the mask created by combining supported change triggers using the bitwise OR operation.

Returns:: a bitwise-OR combination of state change triggers or NONE for a static provider.

getContext


IContext getContext(
Object target)

Returns a help context for the given target. The number of times this method will be called depends on the context change mask. Static context providers will be called each time the owner of the target is activated. If change triggers are used, the method will be called each time the trigger occurs.

Parameters:: target - the focus of the context help
Returns:: context help for the provided target or null if none is defined.

getSearchExpression


String getSearchExpression(
Object target)

Returns a search expression that should be used to find more information about the current target. If provided, it can be used for background search.

Parameters:: target - the focus of the context help
Returns:: search expression as defined by the help system search, or null if background search is not desired.