http://www.eclipse.org/platform: Refactoring Core (Eclipse Foundation) 
Copyright (c) 2000, 2008 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ltk.core.refactoring;


A content stamp object represent the content of an IFile.
A content stamp object is updated whenever the content of a file
changes. In contrast to a time stamp a content stamp is reverted
to its previous value if the content of the file is reverted back by
performing a corresponding undo change.


Clients of the refactoring framework don't need to take care of content
stamps. They are managed by the framework itself.




In version 3.0 not all files in the workspace are annotated with a content stamp. The
refactoring framework only adds content stamp to those files where necessary. As of
version 3.1 the content stamps are mapped to the resource's modification stamp.




Content stamp are to be compared using the equals(Object) method.
It is not guaranteed that content stamps are identical for identical files.




This class is not intended to be extended by clients.



Since:3.0
@noextendThis class is not intended to be subclassed by clients.
/**
 * A content stamp object represent the content of an <code>IFile</code>.
 * A content stamp object is updated whenever the content of a file
 * changes. In contrast to a time stamp a content stamp is reverted
 * to its previous value if the content of the file is reverted back by
 * performing a corresponding undo change.
 * <p>
 * Clients of the refactoring framework don't need to take care of content
 * stamps. They are managed by the framework itself.
 * </p>
 * <p>
 * In version 3.0 not all files in the workspace are annotated with a content stamp. The
 * refactoring framework only adds content stamp to those files where necessary. As of
 * version 3.1 the content stamps are mapped to the resource's modification stamp.
 * </p>
 * <p>
 * Content stamp are to be compared using the <code>equals(Object)</code> method.
 * It is not guaranteed that content stamps are identical for identical files.
 * </p>
 * <p>
 * This class is not intended to be extended by clients.
 * </p>
 *
 * @since 3.0
 *
 * @noextend This class is not intended to be subclassed by clients.
 */
public abstract class ContentStamp {

	
Checks whether the stamp is the null stamp or not. A null stamp
is generated for files which either don't exist or exist in a
closed project.

Returns:whether the stamp is the null stamp or not.
/**
	 * Checks whether the stamp is the null stamp or not. A null stamp
	 * is generated for files which either don't exist or exist in a
	 * closed project.
	 *
	 * @return whether the stamp is the null stamp or not.
	 */
	public abstract boolean isNullStamp();
}