/*

* Copyright (c) 1994, 1998, Oracle and/or its affiliates. All rights reserved.

* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.

*

*

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*/

package java.util;

/**

* A class can implement the <code>Observer</code> interface when it

* wants to be informed of changes in observable objects.

*

* @author Chris Warth

* @see java.util.Observable

* @since JDK1.0

*/

public interface Observer {

/**

* This method is called whenever the observed object is changed. An

* application calls an <tt>Observable</tt> object's

* <code>notifyObservers</code> method to have all the object's

* observers notified of the change.

*

* @param o the observable object.

* @param arg an argument passed to the <code>notifyObservers</code>

* method.

*/

void update(Observable o, Object arg);

}