/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.erlide.engine.model.root;
import org.eclipse.core.resources.IResourceDelta;
import org.erlide.engine.model.IErlElement;
/**
* A Erlang element delta describes changes in Erlang element between two
* discrete points in time. Given a delta, clients can access the element that
* has changed, and any children that have changed.
* <p>
* Deltas have a different status depending on the kind of change they
* represent. The list below summarizes each status (as returned by
* <code>getKind</code>) and its meaning (see individual constants for a more
* detailled description):
* <ul>
* <li><code>ADDED</code>- The element described by the delta has been added.</li>
* <li><code>REMOVED</code>- The element described by the delta has been
* removed.</li>
* <li><code>CHANGED</code>- The element described by the delta has been changed
* in some way. Specification of the type of change is provided by
* <code>getFlags</code> which returns the following values:
* <ul>
* <li><code>F_ADDED_TO_CLASSPATH</code>- 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 <code>IPackageFragmentRoot</code>.</li>
* <li><code>F_CHILDREN</code>- A child of the element has changed in some way.
* This flag is only valid if the element is an <code>IParent</code>.</li>
* <li><code>F_CLASSPATH_REORDER</code>- 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 <code>IPackageFragmentRoot</code>.</li>
* <li><code>F_CLOSED</code>- The underlying <code>IProject</code> has been
* closed. This flag is only valid if the element is an <code>IErlProject</code>
* .</li>
* <li><code>F_CONTENT</code>- The contents of the element have been altered.
* This flag is only valid for elements which correspond to files.</li>
* <li><code>F_FINE_GRAINED</code>- 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.</li>
* <li><code>F_OPENED</code>- The underlying <code>IProject</code> has been
* opened. This flag is only valid if the element is an <code>IErlProject</code>
* .</li>
* <li><code>F_REMOVED_FROM_CLASSPATH</code>- 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 <code>IPackageFragmentRoot</code>.</li>
* </ul>
* </li>
* </ul>
* </p>
* <p>
* 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 <code>REMOVED</code>, with change flag
* <code>F_MOVED_TO</code>. In this case, <code>getMovedToElement</code> on
* delta A will return the handle for B. The delta for B will have status
* <code>ADDED</code>, with change flag <code>F_MOVED_FROM</code>, and
* <code>getMovedFromElement</code> on delta B will return the handle for A.
* (Note, the handle to A in this case represents an element that no longer
* exists).
* </p>
* <p>
* 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.
* </p>
* <p>
* The <code>F_ADDED_TO_CLASSPATH</code>,<code>F_REMOVED_FROM_CLASSPATH</code>
* and <code>F_CLASSPATH_REORDER</code> 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 <code>IErlElementDelta</code> with the
* <code>F_ADDED_TO_CLASSPATH</code> flag for the
* <code>IPackageFragmentRoot</code> 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 <code>IErlElementDelta</code> with
* the <code>ADDED</code>, <code>REMOVED</code>, or <code>CHANGED</code> kind
* will be fired.
* </p>
* <p>
* No assumptions should be made on whether the erlang element delta tree is
* rooted at the <code>IErlModel</code> level or not.
* </p>
* <p>
* <code>IErlElementDelta</code> object are not valid outside the dynamic scope
* of the notification.
* </p>
* <p>
*
* @noimplement This interface is not intended to be implemented by clients.
* </p>
*/
public interface IErlElementDelta {
/**
* 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.
*/
int ADDED = 1;
/**
* 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.
*/
int REMOVED = 2;
/**
* Status constant indicating that the element has been changed, as
* described by the change flags.
*
* @see #getFlags()
*/
int CHANGED = 4;
/**
* Status constant used for getChildren
*/
int ALL = 0;
/**
* Change flag indicating that the content of the element has changed. This
* flag is only valid for elements which correspond to files.
*/
int F_CONTENT = 0x00001;
/**
* Change flag indicating that there are changes to the children of the
* element. This flag is only valid if the element is an
* <code>IParent</code>.
*/
int F_CHILDREN = 0x00008;
/**
* Change flag indicating that the element was moved from another location.
* The location of the old element can be retrieved using
* <code>getMovedFromElement</code>.
*/
int F_MOVED_FROM = 0x00010;
/**
* Change flag indicating that the element was moved to another location.
* The location of the new element can be retrieved using
* <code>getMovedToElement</code>.
*/
int F_MOVED_TO = 0x00020;
/**
* 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 <code>IPackageFragmentRoot</code>.
*/
int F_ADDED_TO_CLASSPATH = 0x00040;
/**
* 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 <code>IPackageFragmentRoot</code>.
*/
int F_REMOVED_FROM_CLASSPATH = 0x00080;
/**
* Change flag indicating that the element has changed position relatively
* to its siblings. If the element is an <code>IPackageFragmentRoot</code>,
* a classpath entry corresponding to the element has changed position in
* the project's classpath.
*
*
*/
int F_REORDER = 0x00100;
/**
* Change flag indicating that the underlying <code>IProject</code> has been
* opened. This flag is only valid if the element is an
* <code>IErlProject</code>.
*/
int F_OPENED = 0x00200;
/**
* Change flag indicating that the underlying <code>IProject</code> has been
* closed. This flag is only valid if the element is an
* <code>IErlProject</code>.
*/
int F_CLOSED = 0x00400;
/**
* 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.
* <p>
* Clients can use this flag to find out if a compilation unit that have a
* <code>F_CONTENT</code> change should assume that there are no finer
* grained changes (<code>F_FINE_GRAINED</code> is set) or if finer grained
* changes were not considered (<code>F_FINE_GRAINED</code> is not set).
*
*
*/
int F_FINE_GRAINED = 0x04000;
/**
* 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
* <code>IErlProject</code>.
*
*
*/
int F_CLASSPATH_CHANGED = 0x20000;
/**
* A source entry added for this resource.
*/
public int F_ADDED_PATHENTRY_SOURCE = 0x0100;
/**
* A source entry was remove for this resource.
*/
public int F_REMOVED_PATHENTRY_SOURCE = 0x0200;
/**
* A pathEntry Macro was added for this resource
*/
public int F_CHANGED_PATHENTRY_MACRO = 0x0400;
/**
* A pathEntry Include was added for this resource
*/
public int F_CHANGED_PATHENTRY_INCLUDE = 0x0800;
/**
* A pathEntry Library was added for this resource
*/
public int F_ADDED_PATHENTRY_LIBRARY = 0x01000;
/**
* A pathEntry Library was added for this resource
*/
public int F_REMOVED_PATHENTRY_LIBRARY = 0x02000;
/**
* A pathEntry Project was added to the project.
*/
public int F_CHANGED_PATHENTRY_PROJECT = 0x04000;
/**
* Reordering of the path entries.
*/
public int F_PATHENTRY_REORDER = 0x040000;
// public int F_SUPER_TYPES = 0x080000;
/**
* Change flag indicating that a source jar has been attached to a binary
* jar.
*/
public int F_SOURCEATTACHED = 0x100000;
/**
* Change flag indicating that a source jar has been detached to a binary
* jar.
*/
public int F_SOURCEDETACHED = 0x200000;
/**
* Returns deltas for the children that have been added, removed or changed
* as specified.
*
* @param kind
* kind of children
*
* @return deltas for the children that have been added
*/
IErlElementDelta[] getChildren(int kind);
/**
* Returns the element that this delta describes a change to.
*
* @return the element that this delta describes a change to
*/
IErlElement getElement();
/**
* Returns flags that describe how an element has changed. Such flags should
* be tested using the <code>&</code> operand. For example:
*
* <pre>
* if ((delta.getFlags() & IErlElementDelta.F_CONTENT) != 0) {
* // the delta indicates a content change
* }
* </pre>
*
* @return flags that describe how an element has changed
*/
int getFlags();
/**
* Returns the kind of this delta - one of <code>ADDED</code>,
* <code>REMOVED</code>, or <code>CHANGED</code>.
*
* @return the kind of this delta
*/
int getKind();
/**
* Returns an element describing this element before it was moved to its
* current location, or <code>null</code> if the <code>F_MOVED_FROM</code>
* change flag is not set.
*
* @return an element describing this element before it was moved to its
* current location, or <code>null</code> if the
* <code>F_MOVED_FROM</code> change flag is not set
*/
IErlElement getMovedFromElement();
/**
* Returns an element describing this element in its new location, or
* <code>null</code> if the <code>F_MOVED_TO</code> change flag is not set.
*
* @return an element describing this element in its new location, or
* <code>null</code> if the <code>F_MOVED_TO</code> change flag is
* not set
*/
IErlElement getMovedToElement();
/**
* Returns the collection of resource deltas.
* <p>
* Note that resource deltas, like Erlang element deltas, are generally only
* valid for the dynamic scope of an event notification. Clients must not
* hang on to these objects.
* </p>
*
* @return the underlying resource deltas, or <code>null</code> if none
*/
IResourceDelta[] getResourceDeltas();
/**
* Find delta with specified element (either this or among children)
*
* @param element
* the element to find
* @return the delta for the specified element
*/
IErlElementDelta findElement(IErlElement element);
}