File	Doc	Category	Size	Date	Package
Observable.java	API Doc	Android 1.5 API	5034	Wed May 06 22:41:04 BST 2009	java.util

Observable

• java.lang.Object

Fields Summary
Vector	observers
boolean	changed

Constructors Summary
public Observable() Constructs a new {@code Observable} object. since Android 1.0 super();

Methods Summary
public synchronized void	addObserver(java.util.Observer observer) Adds the specified observer to the list of observers. If it is already registered, it is not added a second time. param observer the Observer to add. since Android 1.0 if (observer == null) { throw new NullPointerException(); } if (!observers.contains(observer)) observers.addElement(observer);
protected synchronized void	clearChanged() Clears the changed flag for this {@code Observable}. After calling {@code clearChanged()}, {@code hasChanged()} will return {@code false}. since Android 1.0 changed = false;
public synchronized int	countObservers() Returns the number of observers registered to this {@code Observable}. return the number of observers. since Android 1.0 return observers.size();
public synchronized void	deleteObserver(java.util.Observer observer) Removes the specified observer from the list of observers. Passing null won't do anything. param observer the observer to remove. since Android 1.0 observers.removeElement(observer);
public synchronized void	deleteObservers() Removes all observers from the list of observers. since Android 1.0 observers.setSize(0);
public synchronized boolean	hasChanged() Returns the changed flag for this {@code Observable}. return {@code true} when the changed flag for this {@code Observable} is set, {@code false} otherwise. since Android 1.0 return changed;
public void	notifyObservers() If {@code hasChanged()} returns {@code true}, calls the {@code update()} method for every observer in the list of observers using null as the argument. Afterwards, calls {@code clearChanged()}. Equivalent to calling {@code notifyObservers(null)}. since Android 1.0 notifyObservers(null);
public void	notifyObservers(java.lang.Object data) If {@code hasChanged()} returns {@code true}, calls the {@code update()} method for every Observer in the list of observers using the specified argument. Afterwards calls {@code clearChanged()}. param data the argument passed to {@code update()}. since Android 1.0 if (hasChanged()) { // Must clone the vector in case deleteObserver is called Vector<Observer> clone = (Vector<Observer>)observers.clone(); int size = clone.size(); for (int i = 0; i < size; i++) { clone.elementAt(i).update(this, data); } clearChanged(); }
protected synchronized void	setChanged() Sets the changed flag for this {@code Observable}. After calling {@code setChanged()}, {@code hasChanged()} will return {@code true}. since Android 1.0 changed = true;