com.alibaba.nacos.common.utils

类 Observable

java.lang.Object

com.alibaba.nacos.common.utils.Observable

public class Observable
extends Object

Observable utils.

作者:

liaochuntao

构造器概要

构造器

构造器和说明
Observable()

方法概要

限定符和类型	方法和说明
void	addObserver(Observer o) Adds an observer to the set of observers for this object, provided that it is not the same as some observer already in the set.
protected void	clearChanged() Indicates that this object has no longer changed, or that it has already notified all of its observers of its most recent change, so that the hasChanged method will now return false.
int	countObservers() Returns the number of observers of this Observable object.
void	deleteObserver(Observer o) Deletes an observer from the set of observers of this object.
void	deleteObservers() Clears the observer list so that this object no longer has any observers.
boolean	hasChanged() Tests if this object has changed.
void	notifyObservers() If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.
protected void	setChanged() Marks this Observable object as having been changed; the hasChanged method will now return true.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

Observable

public Observable()

方法详细资料

addObserver

public void addObserver(Observer o)

Adds an observer to the set of observers for this object, provided that it is not the same as some observer already in the set. The order in which notifications will be delivered to multiple observers is not specified. See the class comment.

参数:

o - an observer to be added.

抛出:

NullPointerException - if the parameter o is null.

deleteObserver

public void deleteObserver(Observer o)

Deletes an observer from the set of observers of this object. Passing null to this method will have no effect.

参数:

o - the observer to be deleted.

notifyObservers

public void notifyObservers()

If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.

Each observer has its update method called with one argument: this observable object.

deleteObservers

public void deleteObservers()

Clears the observer list so that this object no longer has any observers.

setChanged

protected void setChanged()

Marks this Observable object as having been changed; the hasChanged method will now return true.

clearChanged

protected void clearChanged()

Indicates that this object has no longer changed, or that it has already notified all of its observers of its most recent change, so that the hasChanged method will now return false. This method is called automatically by the notifyObservers methods.

另请参阅:

Observable.notifyObservers(), Observable.notifyObservers(java.lang.Object)

hasChanged

public boolean hasChanged()

Tests if this object has changed.

返回:

true if and only if the setChanged method has been called more recently than the clearChanged method on this object; false otherwise.

countObservers

public int countObservers()

Returns the number of observers of this Observable object.

返回:

the number of observers of this object.