model/org/eclipse/jdt/core/IJavaElementDelta.java

/**********************************************************************
Copyright (c) 2000, 2001, 2002 IBM Corp. and others.
All rights reserved.   This program and the accompanying materials
are made available under the terms of the Common Public License v0.5
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/cpl-v05.html
 
Contributors:
     IBM Corporation - initial API and implementation
**********************************************************************/
package org.eclipse.jdt.core;

import org.eclipse.core.resources.IResourceDelta;

/**
 * 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.
 * <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:
 * <ul>
 * <li><code>ADDED</code> - The element described by the delta 
 * has been added. Additional information is specified by
 * <code>getFlags</code> which returns <code>F_ADDED_TO_CLASSPATH</code>
 * if the element added is a package fragment root on the classpath.</li>
 * <li><code>REMOVED</code> - The element described by the delta 
 * has been removed. Additional information is specified by
 * <code>getFlags</code> which returns <code>F_REMOVED_FROM_CLASSPATH</code>
 * if the element removed was a package fragment root on the classpath.</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_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_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_MODIFIERS</code> - the modifiers on the element have changed in some way. 
 * This flag is only valid if the element is an <code>IMember</code>.</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>IJavaModel</code>
 * or an <code>IJavaProject</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>IJavaModel</code>
 * or an <code>IJavaProject</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 following flags describe changes in an <code>IJavaProject</code>'s classpath:
 * <ul>
 * <li><code>F_ADDED_TO_CLASSPATH</code> - the element described by the delta has been added to the
 *	classpath.</li>
 * <li><code>F_REMOVED_FROM_CLASSPATH</code> - the element described by the delta has been removed
 * from the classpath.</li>
 * <li><code>F_CLASSPATH_REORDER</code> - the element described by the delta has changed its
 * position in the classpath.</li>
 * </ul>
 * </p>
 * <p>
 * <code>IJavaElementDelta</code> object are not valid outside the dynamic scope
 * of the notification.
 * </p>
 * <p>
 * This interface is not intended to be implemented by clients.
 * </p>
 */
public interface IJavaElementDelta {

	/**
	 * Status constant indicating that the element has been added.
	 */
	public int ADDED = 1;

	/**
	 * Status constant indicating that the element has been removed.
	 */
	public int REMOVED = 2;

	/**
	 * Status constant indicating that the element has been changed,
	 * as described by the change flags.
	 */
	public int CHANGED = 4;

	/**
	 * Change flag indicating that the content of the element has changed.
	 */
	public int F_CONTENT = 0x0001;

	/**
	 * Change flag indicating that the modifiers of the element have changed.
	 */
	public int F_MODIFIERS = 0x0002;

	/**
	 * Change flag indicating that there are changes to the children of the element.
	 */
	public int F_CHILDREN = 0x0008;

	/**
	 * Change flag indicating that the element was moved from another location.
	 * The location of the old element can be retrieved using <code>getMovedFromElement</code>.
	 */
	public int F_MOVED_FROM = 0x0010;

	/**
	 * Change flag indicating that the element was moved to another location.
	 * The location of the new element can be retrieved using <code>getMovedToElement</code>.
	 */
	public int F_MOVED_TO = 0x0020;

	/**
	 * Change flag indicating that the element was added to the classpath. In this
	 * case the element is an <code>IPackageFragmentRoot</code>.
	 */
	public int F_ADDED_TO_CLASSPATH = 0x0040;

	/**
	 * Change flag indicating that the element was removed from the classpath. In this
	 * case the element is an <code>IPackageFragmentRoot</code>.
	 */
	public int F_REMOVED_FROM_CLASSPATH = 0x0080;

	/**
	 * Change flag indicating that the element's position in the classpath has changed.
	 * In this case the element is an <code>IPackageFragmentRoot</code>.
	 */
	public int F_CLASSPATH_REORDER = 0x0100;

	/**
	 * Change flag indicating that the underlying <code>IProject</code> has been
	 * opened.
	 */
	public int F_OPENED = 0x0200;

	/**
	 * Change flag indicating that the underlying <code>IProject</code> has been
	 * closed.
	 */
	public int F_CLOSED = 0x0400;

	/**
	 * Change flag indicating that one of the supertypes of an <code>IType</code>
	 * has changed.
	 */
	public int F_SUPER_TYPES = 0x0800;

	/**
	 * Change flag indicating that a source jar has been attached to a binary jar.
	 */
	public int F_SOURCEATTACHED = 0x1000;	

	/**
	 * Change flag indicating that a source jar has been detached to a binary jar.
	 */
	public int F_SOURCEDETACHED = 0x2000;	
	
	/**
	 * Change flag indicating that this is a fine-grained delta, i.e.&nbsp;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). 
	 */
	public int F_FINE_GRAINED = 0x4000;
/**
 * Returns deltas for the children that have been added.
 */
public IJavaElementDelta[] getAddedChildren();
/**
 * Returns deltas for the affected (added, removed, or changed) children.
 */
public IJavaElementDelta[] getAffectedChildren();
/**
 * Returns deltas for the children which have changed.
 */
public IJavaElementDelta[] getChangedChildren();
/**
 * Returns the element that this delta describes a change to.
 */
public IJavaElement getElement();
/**
 * Returns flags that describe how an element has changed.
 *
 * @see IJavaElementDelta#F_CHILDREN
 * @see IJavaElementDelta#F_CONTENT
 * @see IJavaElementDelta#F_MODIFIERS
 * @see IJavaElementDelta#F_MOVED_FROM
 * @see IJavaElementDelta#F_MOVED_TO
 * @see IJavaElementDelta#F_ADDED_TO_CLASSPATH
 * @see IJavaElementDelta#F_REMOVED_FROM_CLASSPATH
 * @see IJavaElementDelta#F_CLASSPATH_REORDER
 */
public int getFlags();
/**
 * Returns the kind of this delta - one of <code>ADDED</code>, <code>REMOVED</code>,
 * or <code>CHANGED</code>.
 */
public 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. 
 */
public IJavaElement 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.
 */
public IJavaElement getMovedToElement();
/**
 * Returns deltas for the children which have been removed.
 */
public IJavaElementDelta[] getRemovedChildren();
/**
 * Returns the collection of resource deltas.
 * <p>
 * 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.
 * </p>
 *
 * @return the underlying resource deltas, or <code>null</code> if none
 */
public IResourceDelta[] getResourceDeltas();
}