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Java.util.Observable.deleteObserver() Method
Description
The java.util.Observable.deleteObserver(Observer o) method deletes the specified observer o from the set of observers of this object.
Declaration
Following is the declaration for java.util.Observable.deleteObserver() method
public void deleteObserver(Observer o)
Parameters
o − The observer to be deleted from the set of observers.
Return Value
NA
Exception
NA
Example
The following example shows the usage of java.util.Observable.deleteObserver(Observer) method.
package com.tutorialspoint; import java.util.Observable; import java.util.Observer; class ObservedObject extends Observable { private String watchedValue; public ObservedObject(String value) { watchedValue = value; } public void setValue(String value) { // if value has changed notify observers if(!watchedValue.equals(value)) { System.out.println("Value changed to new value: "+value); watchedValue = value; // mark as value changed setChanged(); // trigger notification notifyObservers(value); } } } public class ObservableDemo implements Observer { public static void main(String[] args) { // create watched and watcher objects ObservedObject watched = new ObservedObject("Original Value"); // watcher object listens to object change ObservableDemo watcher = new ObservableDemo(); // trigger value change watched.setValue("Value before addObserver"); // add observer to the watched object watched.addObserver(watcher); // trigger value change watched.setValue("Value after addObserver"); // delete observer watched.deleteObserver(watcher); // trigger value change watched.setValue("Value after deleteObserver"); } public void update(Observable obj, Object arg) { System.out.println("Update called with Arguments: "+arg); } }
Let us compile and run the above program, this will produce the following result −
Value changed to new value: Value before addObserver Value changed to new value: Value after addObserver Update called with Arguments: Value after addObserver Value changed to new value: Value after deleteObserver
java_util_observable.htm
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