全局Listeners持有者

Java监听器模式实践

最新推荐文章于 2021-11-08 14:44:21 发布

原创最新推荐文章于 2021-11-08 14:44:21 发布 · 936 阅读

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本文介绍了一种基于Java实现的监听器模式，通过定义接口和抽象类来简化事件处理过程。该模式支持不同类型的监听器，并利用泛型和反射机制实现了灵活的事件分发。

package com.test;

public interface IBaseListener {
}

package com.test;

public interface OnXListener extends IBaseListener {
	public void onXyes();

	public void onXno();

	public static class AbsOnXListener implements OnXListener {
		@Override
		public void onXyes() {
		}

		@Override
		public void onXno() {
		}
	}
}

package com.test;

public interface OnYListener extends IBaseListener {
	public void onYyes(String s);

	public void onYno(String s);

	public static abstract class AbsOnYListener implements OnYListener {
		@Override
		public void onYyes(String s) {
		}

		@Override
		public void onYno(String s) {
		}
	}
}

package com.test;

import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

public class ListenerHolder {
	private static Set<OnXListener> sXListeners = new CopyOnWriteArraySet<OnXListener>();
	private static Set<OnYListener> sYListeners = new CopyOnWriteArraySet<OnYListener>();

	@SuppressWarnings({ "unchecked" })
	public static <T extends IBaseListener> void callListeners(Class<T> clz, IListenerExecutor<T> executor) {
		if (OnXListener.class.isAssignableFrom(clz)) {
			for (OnXListener listener : sXListeners) {
				executor.execute((T) listener);
			}
		} else if (OnYListener.class.isAssignableFrom(clz)) {
			for (OnYListener listener : sYListeners) {
				executor.execute((T) listener);
			}
		}
	}

	public static void addListener(IBaseListener listener) {
		if (listener instanceof OnXListener) {
			sXListeners.add((OnXListener) listener);
		}
		if (listener instanceof OnYListener) {
			sYListeners.add((OnYListener) listener);
		}
	}

	public static void removeListener(IBaseListener listener) {
		if (listener instanceof OnXListener) {
			sXListeners.remove(listener);
		}
		if (listener instanceof OnYListener) {
			sYListeners.remove(listener);
		}
	}

	public static void clear() {
		sXListeners.clear();
		sYListeners.clear();
	}

	public static interface IListenerExecutor<T extends IBaseListener> {
		public void execute(T listener);
	}

}

package com.test;

import com.test.ListenerHolder.IListenerExecutor;

public class Test {
	public static void main(String[] args) {
		// 触发监听器
		final String s = "abc";
		ListenerHolder.callListeners(OnYListener.class, new IListenerExecutor<OnYListener>() {
			@Override
			public void execute(OnYListener listener) {
				listener.onYyes(s);
			}
		});
	}
	
	// 添加监听器
	public void addListener(IBaseListener listener) {
		ListenerHolder.addListener(listener);
	}
	
	// 移除监听器
	public void removeListener(IBaseListener listener) {
		ListenerHolder.removeListener(listener);
	}
	
}