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

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Eclipse Platform
Release 3.5

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org.eclipse.core.resources
Interface ISaveContext

public interface ISaveContext

A context for workspace save operations.

Note that IWorkspace.save uses a different save context for each registered participant, allowing each to declare whether they have actively participated and decide whether to receive a resource delta on reactivation.

See Also:: IWorkspace.save(boolean, org.eclipse.core.runtime.IProgressMonitor)
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 int FULL_SAVE
          Type constant which identifies a full save.

static int PROJECT_SAVE
          Type constant which identifies a project save.

static int SNAPSHOT
          Type constant which identifies a snapshot.

Method Summary

IPath[] getFiles ()
          Returns current files mapped with the ISaveContext.map facility or an empty array if there are no mapped files.

int getKind ()
          Returns the type of this save.

int getPreviousSaveNumber ()
          Returns the number for the previous save in which the plug-in actively participated, or 0 if the plug-in has never actively participated in a save before.

IProject getProject ()
          If the current save is a project save, this method returns the project being saved.

int getSaveNumber ()
          Returns the number for this save.

IPath lookup ( IPath file)
          Returns the current location for the given file or null if none.

void map ( IPath file, IPath location)
          Maps the given plug-in file to its real location.

void needDelta ()
          Indicates that the saved workspace tree should be remembered so that a delta will be available in a subsequent session when the plug-in re-registers to participate in saves.

void needSaveNumber ()
          Indicates that this participant has actively participated in this save.

Field Detail

FULL_SAVE

static final int FULL_SAVE

Type constant which identifies a full save.

See Also:: getKind(), Constant Field Values

SNAPSHOT

static final int SNAPSHOT

Type constant which identifies a snapshot.

See Also:: getKind(), Constant Field Values

PROJECT_SAVE

static final int PROJECT_SAVE

Type constant which identifies a project save.

See Also:: getKind(), Constant Field Values

Method Detail

getFiles


IPath[] getFiles()

Returns current files mapped with the ISaveContext.map facility or an empty array if there are no mapped files.

Returns:: the files currently mapped by the participant
See Also:: map(IPath, IPath)

getKind

int getKind()

Returns the type of this save. The types can be:

ISaveContext.FULL_SAVE
ISaveContext.SNAPSHOT
ISaveContext.PROJECT_SAVE

Returns:: the type of the current save

getPreviousSaveNumber

int getPreviousSaveNumber()

Returns the number for the previous save in which the plug-in actively participated, or 0 if the plug-in has never actively participated in a save before.

In the event of an unsuccessful save, this is the value to rollback to.

Returns:: the previous save number if positive, or 0 if never saved before
See Also:: ISaveParticipant.rollback(ISaveContext)

getProject


IProject getProject()

If the current save is a project save, this method returns the project being saved.

Returns:: the project being saved or null if this is not project save
See Also:: getKind()

getSaveNumber

int getSaveNumber()

Returns the number for this save. This number is guaranteed to be 1 more than the previous save number.

This is the value to use when, for example, creating files in which a participant will save its data.

Returns:: the save number
See Also:: ISaveParticipant.saving(ISaveContext)

lookup


IPath lookup(
IPath file)

Returns the current location for the given file or null if none.

Returns:: the location of a given file or null
See Also:: map(IPath, IPath), ISavedState.lookup(IPath)

map

void map(
IPath file,
         
IPath location)

Maps the given plug-in file to its real location. This method is intended to be used with ISaveContext.getSaveNumber() to map plug-in configuration file names to real locations.

For example, assume a plug-in has a configuration file named "config.properties". The map facility can be used to map that logical name onto a real name which is specific to a particular save (e.g., 10.config.properties, where 10 is the current save number). The paths specified here should always be relative to the plug-in state location for the plug-in saving the state.

Each save participant must manage the deletion of its old state files. Old state files can be discovered using getPreviousSaveNumber or by using getFiles to discover the current files and comparing that to the list of files on disk.

Parameters:: file - the logical name of the participant's data file; location - the real (i.e., filesystem) name by which the file should be known for this save, or null to remove the entry
See Also:: lookup(IPath), getSaveNumber(), needSaveNumber(), ISavedState.lookup(IPath)

needDelta

void needDelta()

Indicates that the saved workspace tree should be remembered so that a delta will be available in a subsequent session when the plug-in re-registers to participate in saves. If this method is not called, no resource delta will be made available. This facility is not available for marker deltas. Plug-ins must assume that all markers may have changed when they are activated.

Note that this is orthogonal to needSaveNumber. That is, one can ask for a delta regardless of whether or not one is an active participant.

Note that deltas are not guaranteed to be saved even if saving is requested. Deltas cannot be supplied where the previous state is too old or has become invalid.

This method is only valid for full saves. It is ignored during snapshots or project saves.

See Also:: IWorkspace.addSaveParticipant(org.eclipse.core.runtime.Plugin, ISaveParticipant), ISavedState.processResourceChangeEvents(IResourceChangeListener)

needSaveNumber

void needSaveNumber()

Indicates that this participant has actively participated in this save. If the save is successful, the current save number will be remembered; this save number will be the previous save number for subsequent saves until the participant again actively participates.

If this method is not called, the plug-in is not deemed to be an active participant in this save.

Note that this is orthogonal to needDelta. That is, one can be an active participant whether or not one asks for a delta.