Overview | Package | Class | Use | Tree | Deprecated | Index | Help
| Java™ Platform Standard Ed. 6
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## java.util
Interface Observer

    public interface Observer

A class can implement the `Observer` interface when it wants to be informed of changes in observable objects.

Since:
  JDK1.0
See Also:
  `Observable`

Method Summary
`void` | `update(Observable o, Object arg)` This method is called whenever the observed object is changed.

Method Detail

### update

    void update(Observable o,
                Object arg)

  This method is called whenever the observed object is changed. An application calls an `Observable` object's `notifyObservers` method to have all the object's observers notified of the change.

  Parameters:
    `o` - the observable object.
    `arg` - an argument passed to the `notifyObservers` method.

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
| Java™ Platform Standard Ed. 6
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

Submit a bug or feature
For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2009 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.