使用Java标准的java.util.EventListener实现观察者-发布者设计模式---Jerry Wang

package eventlistener; import java.util.EventListener; public interface ISwitchListener extends EventListener { public void switchEvent(SwitchEvent event); }package eventlistener; import java.util.EventObject; @SuppressWarnings("serial") public class SwitchEvent extends EventObject implements Cloneable { private String switchState = ""; public SwitchEvent(Object source, String switchState) { super(source); this.switchState = switchState; } public void setSwitchState(String switchState) { this.switchState = switchState; } public String getSwitchState() { return this.switchState; } }package eventlistener; import java.util.Collection; import java.util.HashSet; import java.util.Iterator; public class SwitchManager { private Collection<ISwitchListener> listeners; public void addDoorListener(ISwitchListener listener) { if (listeners == null) { listeners = new HashSet<ISwitchListener>(); } listeners.add(listener); } public void removeDoorListener(ISwitchListener listener) { if (listeners == null) return; listeners.remove(listener); } protected void fireSwitchOn() { if (listeners == null) return; SwitchEvent event = new SwitchEvent(this, "open"); notifyListeners(event); } protected void fireSwitchOff() { if (listeners == null) return; SwitchEvent event = new SwitchEvent(this, "close"); notifyListeners(event); } private void notifyListeners(SwitchEvent event) { Iterator<ISwitchListener> iter = listeners.iterator(); while (iter.hasNext()) { ISwitchListener listener = (ISwitchListener) iter.next(); listener.switchEvent(event); } } }package eventlistener; public class SwitchTest { public static void main(String[] args) { SwitchManager manager = new SwitchManager(); manager.addDoorListener(new TVSwitchListener()); manager.fireSwitchOn(); manager.fireSwitchOff(); } }package eventlistener; public class TVSwitchListener implements ISwitchListener { @Override public void switchEvent(SwitchEvent event) { if (event.getSwitchState() != null && event.getSwitchState().equals("open")) { System.out.println("open TV"); } else { System.out.println("close TV"); } } } ---来自腾讯云社区的---Jerry Wang