Eclipse JDT Plug-in Developer Guide (Galileo) - IJavaElementDelta (Eclipse JDT API Specification)

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org.eclipse.jdt.core
Interface IJavaElementDelta

public interface IJavaElementDelta

A Java element delta describes changes in Java element between two discrete points in time. Given a delta, clients can access the element that has changed, and any children that have changed.

Deltas have a different status depending on the kind of change they represent. The list below summarizes each status (as returned by getKind()) and its meaning (see individual constants for a more detailled description):

ADDED - The element described by the delta has been added.
REMOVED - The element described by the delta has been removed.
CHANGED - The element described by the delta has been changed in some way. Specification of the type of change is provided by getFlags() which returns the following values:
- F_ADDED_TO_CLASSPATH - A classpath entry corresponding to the element has been added to the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.
- F_ARCHIVE_CONTENT_CHANGED - The contents of an archive has changed in some way. This flag is only valid if the element is an IPackageFragmentRoot which is an archive.
- F_CHILDREN - A child of the element has changed in some way. This flag is only valid if the element is an IParent.
- F_CLASSPATH_REORDER - A classpath entry corresponding to the element has changed position in the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.
- F_CLOSED - The underlying IProject has been closed. This flag is only valid if the element is an IJavaProject.
- F_CONTENT - The contents of the element have been altered. This flag is only valid for elements which correspond to files.
- F_FINE_GRAINED - The delta is a fine-grained delta, that is, an analysis down to the members level was done to determine if there were structural changes to members of the element.
- F_MODIFIERS - The modifiers on the element have changed in some way. This flag is only valid if the element is an IMember.
- F_OPENED - The underlying IProject has been opened. This flag is only valid if the element is an IJavaProject.
- F_REMOVED_FROM_CLASSPATH - A classpath entry corresponding to the element has been removed from the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.
- F_SOURCEATTACHED - The source attachment path or the source attachment root path of a classpath entry corresponding to the element was added. This flag is only valid if the element is an IPackageFragmentRoot.
- F_SOURCEDETACHED - The source attachment path or the source attachment root path of a classpath entry corresponding to the element was removed. This flag is only valid if the element is an IPackageFragmentRoot.
- F_SUPER_TYPES - One of the supertypes of an IType has changed

Move operations are indicated by other change flags, layered on top of the change flags described above. If element A is moved to become B, the delta for the change in A will have status REMOVED, with change flag F_MOVED_TO. In this case, getMovedToElement() on delta A will return the handle for B. The delta for B will have status ADDED, with change flag F_MOVED_FROM, and getMovedFromElement() on delta B will return the handle for A. (Note, the handle to A in this case represents an element that no longer exists).

Note that the move change flags only describe the changes to a single element, they do not imply anything about the parent or children of the element.

The F_ADDED_TO_CLASSPATH, F_REMOVED_FROM_CLASSPATH and F_CLASSPATH_REORDER flags are triggered by changes to a project's classpath. They do not mean that the underlying resource was added, removed or changed. For example, if a project P already contains a folder src, then adding a classpath entry with the 'P/src' path to the project's classpath will result in an IJavaElementDelta with the F_ADDED_TO_CLASSPATH flag for the IPackageFragmentRoot P/src. On the contrary, if a resource is physically added, removed or changed and this resource corresponds to a classpath entry of the project, then an IJavaElementDelta with the ADDED, REMOVED, or CHANGED kind will be fired.

Note that when a source attachment path or a source attachment root path is changed, then the flags of the delta contain both F_SOURCEATTACHED and F_SOURCEDETACHED.

No assumptions should be made on whether the java element delta tree is rooted at the IJavaModel level or not.

IJavaElementDelta object are not valid outside the dynamic scope of the notification.

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

Field Summary

static int ADDED
          Status constant indicating that the element has been added.

static int CHANGED
          Status constant indicating that the element has been changed, as described by the change flags.

static int F_ADDED_TO_CLASSPATH
          Change flag indicating that a classpath entry corresponding to the element has been added to the project's classpath.

static int F_ANNOTATIONS
          Change flag indicating that the annotations of the element have changed.

static int F_ARCHIVE_CONTENT_CHANGED
          Change flag indicating that the element's archive content on the classpath has changed.

static int F_AST_AFFECTED
          Change flag indicating that a reconcile operation has affected the compilation unit AST created in a previous reconcile operation.

static int F_CATEGORIES
          Change flag indicating that the categories of the element have changed.

static int F_CHILDREN
          Change flag indicating that there are changes to the children of the element.

static int F_CLASSPATH_CHANGED
          Change flag indicating that the raw classpath (or the output folder) of a project has changed.

static int F_CLASSPATH_REORDER
          Deprecated. Use F_REORDER instead.

static int F_CLOSED
          Change flag indicating that the underlying IProject has been closed.

static int F_CONTENT
          Change flag indicating that the content of the element has changed.

static int F_FINE_GRAINED
          Change flag indicating that this is a fine-grained delta, that is, an analysis down to the members level was done to determine if there were structural changes to members.

static int F_MODIFIERS
          Change flag indicating that the modifiers of the element have changed.

static int F_MOVED_FROM
          Change flag indicating that the element was moved from another location.

static int F_MOVED_TO
          Change flag indicating that the element was moved to another location.

static int F_OPENED
          Change flag indicating that the underlying IProject has been opened.

static int F_PRIMARY_RESOURCE
          Change flag indicating that the resource of a primary compilation unit has changed.

static int F_PRIMARY_WORKING_COPY
          Change flag indicating that a compilation unit has become a primary working copy, or that a primary working copy has reverted to a compilation unit.

static int F_REMOVED_FROM_CLASSPATH
          Change flag indicating that a classpath entry corresponding to the element has been removed from the project's classpath.

static int F_REORDER
          Change flag indicating that the element has changed position relatively to its siblings.

static int F_RESOLVED_CLASSPATH_CHANGED
          Change flag indicating that the resolved classpath of a project has changed.

static int F_SOURCEATTACHED
          Change flag indicating that the source attachment path or the source attachment root path of a classpath entry corresponding to the element was added.

static int F_SOURCEDETACHED
          Change flag indicating that the source attachment path or the source attachment root path of a classpath entry corresponding to the element was removed.

static int F_SUPER_TYPES
          Change flag indicating that one of the supertypes of an IType has changed.

static int REMOVED
          Status constant indicating that the element has been removed.

Method Summary

IJavaElementDelta[] getAddedChildren ()
          Returns deltas for the children that have been added.

IJavaElementDelta[] getAffectedChildren ()
          Returns deltas for the affected (added, removed, or changed) children.

IJavaElementDelta[] getAnnotationDeltas ()
          Returns deltas for affected annotations (added, removed, or changed).

IJavaElementDelta[] getChangedChildren ()
          Returns deltas for the children which have changed.

CompilationUnit getCompilationUnitAST ()
          Returns the compilation unit AST created by the last reconcile operation on this delta's element.

IJavaElement getElement ()
          Returns the element that this delta describes a change to.

int getFlags ()
          Returns flags that describe how an element has changed.

int getKind ()
          Returns the kind of this delta - one of ADDED, REMOVED, or CHANGED.

IJavaElement getMovedFromElement ()
          Returns an element describing this element before it was moved to its current location, or null if the F_MOVED_FROM change flag is not set.

IJavaElement getMovedToElement ()
          Returns an element describing this element in its new location, or null if the F_MOVED_TO change flag is not set.

IJavaElementDelta[] getRemovedChildren ()
          Returns deltas for the children which have been removed.

IResourceDelta[] getResourceDeltas ()
          Returns the collection of resource deltas.

Field Detail

ADDED

static final int ADDED

Status constant indicating that the element has been added. Note that an added java element delta has no children, as they are all implicitely added.

See Also:: Constant Field Values

REMOVED

static final int REMOVED

Status constant indicating that the element has been removed. Note that a removed java element delta has no children, as they are all implicitely removed.

See Also:: Constant Field Values

CHANGED

static final int CHANGED

Status constant indicating that the element has been changed, as described by the change flags.

See Also:: getFlags(), Constant Field Values

F_CONTENT

static final int F_CONTENT

Change flag indicating that the content of the element has changed. This flag is only valid for elements which correspond to files.

See Also:: Constant Field Values

F_MODIFIERS

static final int F_MODIFIERS

Change flag indicating that the modifiers of the element have changed. This flag is only valid if the element is an IMember.

See Also:: Constant Field Values

F_CHILDREN

static final int F_CHILDREN

Change flag indicating that there are changes to the children of the element. This flag is only valid if the element is an IParent.

See Also:: Constant Field Values

F_MOVED_FROM

static final int F_MOVED_FROM

Change flag indicating that the element was moved from another location. The location of the old element can be retrieved using getMovedFromElement().

See Also:: Constant Field Values

F_MOVED_TO

static final int F_MOVED_TO

Change flag indicating that the element was moved to another location. The location of the new element can be retrieved using getMovedToElement().

See Also:: Constant Field Values

F_ADDED_TO_CLASSPATH

static final int F_ADDED_TO_CLASSPATH

Change flag indicating that a classpath entry corresponding to the element has been added to the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.

See Also:: Constant Field Values

F_REMOVED_FROM_CLASSPATH

static final int F_REMOVED_FROM_CLASSPATH

Change flag indicating that a classpath entry corresponding to the element has been removed from the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.

See Also:: Constant Field Values

F_CLASSPATH_REORDER

static final int F_CLASSPATH_REORDER

Deprecated. Use F_REORDER instead.

Change flag indicating that a classpath entry corresponding to the element has changed position in the project's classpath. This flag is only valid if the element is an IPackageFragmentRoot.

See Also:: Constant Field Values

F_REORDER

static final int F_REORDER

Change flag indicating that the element has changed position relatively to its siblings. If the element is an IPackageFragmentRoot, a classpath entry corresponding to the element has changed position in the project's classpath.

Since:: 2.1
See Also:: Constant Field Values

F_OPENED

static final int F_OPENED

Change flag indicating that the underlying IProject has been opened. This flag is only valid if the element is an IJavaProject.

See Also:: Constant Field Values

F_CLOSED

static final int F_CLOSED

Change flag indicating that the underlying IProject has been closed. This flag is only valid if the element is an IJavaProject.

See Also:: Constant Field Values

F_SUPER_TYPES

static final int F_SUPER_TYPES

Change flag indicating that one of the supertypes of an IType has changed.

See Also:: Constant Field Values

F_SOURCEATTACHED

static final int F_SOURCEATTACHED

Change flag indicating that the source attachment path or the source attachment root path of a classpath entry corresponding to the element was added. This flag is only valid if the element is an IPackageFragmentRoot.

See Also:: Constant Field Values

F_SOURCEDETACHED

static final int F_SOURCEDETACHED

Change flag indicating that the source attachment path or the source attachment root path of a classpath entry corresponding to the element was removed. This flag is only valid if the element is an IPackageFragmentRoot.

See Also:: Constant Field Values

F_FINE_GRAINED

static final int F_FINE_GRAINED

Change flag indicating that this is a fine-grained delta, that is, an analysis down to the members level was done to determine if there were structural changes to members.

Clients can use this flag to find out if a compilation unit that have a F_CONTENT change should assume that there are no finer grained changes ( F_FINE_GRAINED is set) or if finer grained changes were not considered ( F_FINE_GRAINED is not set).

Since:: 2.0
See Also:: Constant Field Values

F_ARCHIVE_CONTENT_CHANGED

static final int F_ARCHIVE_CONTENT_CHANGED

Change flag indicating that the element's archive content on the classpath has changed. This flag is only valid if the element is an IPackageFragmentRoot which is an archive.

Since:: 2.0
See Also:: IPackageFragmentRoot.isArchive(), Constant Field Values

F_PRIMARY_WORKING_COPY

static final int F_PRIMARY_WORKING_COPY

Change flag indicating that a compilation unit has become a primary working copy, or that a primary working copy has reverted to a compilation unit. This flag is only valid if the element is an ICompilationUnit.

Since:: 3.0
See Also:: Constant Field Values

F_CLASSPATH_CHANGED

static final int F_CLASSPATH_CHANGED

Change flag indicating that the raw classpath (or the output folder) of a project has changed. This flag is only valid if the element is an IJavaProject. Also see F_RESOLVED_CLASSPATH_CHANGED, which indicates that there is a change to the resolved class path. The resolved classpath can change without the raw classpath changing (e.g. if a container resolves to a different set of classpath entries). And conversely, it is possible to construct a case where the raw classpath can change without the resolved classpath changing.

Since:: 3.0
See Also:: Constant Field Values

F_PRIMARY_RESOURCE

static final int F_PRIMARY_RESOURCE

Change flag indicating that the resource of a primary compilation unit has changed. This flag is only valid if the element is a primary ICompilationUnit.

Since:: 3.0
See Also:: Constant Field Values

F_AST_AFFECTED

static final int F_AST_AFFECTED

Change flag indicating that a reconcile operation has affected the compilation unit AST created in a previous reconcile operation. Use getCompilationUnitAST() to retrieve the AST (if any is available). This flag is only valid if the element is an ICompilationUnit in working copy mode.

Since:: 3.2
See Also:: Constant Field Values

F_CATEGORIES

static final int F_CATEGORIES

Change flag indicating that the categories of the element have changed. This flag is only valid if the element is an IMember.

Since:: 3.2
See Also:: Constant Field Values

F_RESOLVED_CLASSPATH_CHANGED

static final int F_RESOLVED_CLASSPATH_CHANGED

Change flag indicating that the resolved classpath of a project has changed. This flag is only valid if the element is an IJavaProject. Also see F_CLASSPATH_CHANGED, which indicates that there is a change to the raw class path. The resolved classpath can change without the raw classpath changing (e.g. if a container resolves to a different set of classpath entries). And conversely, it is possible to construct a case where the raw classpath can change without the resolved classpath changing.

Since:: 3.4
See Also:: Constant Field Values

F_ANNOTATIONS

static final int F_ANNOTATIONS

Change flag indicating that the annotations of the element have changed. Use getAnnotationDeltas() to get the added/removed/changed annotations. This flag is only valid if the element is an IAnnotatable.

Since:: 3.4
See Also:: Constant Field Values

Method Detail

getAddedChildren


IJavaElementDelta[] getAddedChildren()

Returns deltas for the children that have been added.

Returns:: deltas for the children that have been added

getAffectedChildren


IJavaElementDelta[] getAffectedChildren()

Returns deltas for the affected (added, removed, or changed) children.

Returns:: deltas for the affected (added, removed, or changed) children

getAnnotationDeltas


IJavaElementDelta[] getAnnotationDeltas()

Returns deltas for affected annotations (added, removed, or changed). Returns an empty array if no annotations was affected, or if this delta's element is not an IAnnotatable.

Returns:: deltas for affected annotations (added, removed, or changed)
Since:: 3.4

getCompilationUnitAST


CompilationUnit getCompilationUnitAST()

Returns the compilation unit AST created by the last reconcile operation on this delta's element. This returns a non-null value if and only if:

the last reconcile operation on this working copy requested an AST
this delta's element is an ICompilationUnit in working copy mode
the delta comes from a ElementChangedEvent.POST_RECONCILE event

Returns:: the AST created during the last reconcile operation
Since:: 3.2
See Also:: ICompilationUnit.reconcile(int, boolean, WorkingCopyOwner, org.eclipse.core.runtime.IProgressMonitor), F_AST_AFFECTED

getChangedChildren


IJavaElementDelta[] getChangedChildren()

Returns deltas for the children which have changed.

Returns:: deltas for the children which have changed

getElement


IJavaElement getElement()

Returns the element that this delta describes a change to.

Returns:: the element that this delta describes a change to

getFlags

int getFlags()

Returns flags that describe how an element has changed. Such flags should be tested using the & operand. For example:

 if ((delta.getFlags() & IJavaElementDelta.F_CONTENT) != 0) {
        // the delta indicates a content change
 }

Returns:: flags that describe how an element has changed

getKind

int getKind()

Returns the kind of this delta - one of ADDED, REMOVED, or CHANGED.

Returns:: the kind of this delta

getMovedFromElement


IJavaElement getMovedFromElement()

Returns an element describing this element before it was moved to its current location, or null if the F_MOVED_FROM change flag is not set.

Returns:: an element describing this element before it was moved to its current location, or null if the F_MOVED_FROM change flag is not set

getMovedToElement


IJavaElement getMovedToElement()

Returns an element describing this element in its new location, or null if the F_MOVED_TO change flag is not set.

Returns:: an element describing this element in its new location, or null if the F_MOVED_TO change flag is not set

getRemovedChildren


IJavaElementDelta[] getRemovedChildren()

Returns deltas for the children which have been removed.

Returns:: deltas for the children which have been removed

getResourceDeltas


IResourceDelta[] getResourceDeltas()

Returns the collection of resource deltas.

Note that resource deltas, like Java element deltas, are generally only valid for the dynamic scope of an event notification. Clients must not hang on to these objects.

Returns:: the underlying resource deltas, or null if none