Cleaner
Cleaner 是 Java 9 引入的资源清理机制,用于在对象被垃圾回收后自动或手动执行清理操作,替代 finalize(),安全、异步且高效。
java
public final class Cleaner {
final CleanerImpl impl;
static {
CleanerImpl.setCleanerImplAccess(new Function<Cleaner, CleanerImpl>() {
@Override
public CleanerImpl apply(Cleaner cleaner) {
return cleaner.impl;
}
});
}
private Cleaner() {
impl = new CleanerImpl();
}
// 创建一个新的 Cleaner,使用默认后台守护线程处理清理任务。
public static Cleaner create() {
Cleaner cleaner = new Cleaner();
cleaner.impl.start(cleaner, null);
return cleaner;
}
// 使用指定线程工厂创建 Cleaner,适合自定义线程配置(如优先级、命名)。
public static Cleaner create(ThreadFactory threadFactory) {
Objects.requireNonNull(threadFactory, "threadFactory");
Cleaner cleaner = new Cleaner();
cleaner.impl.start(cleaner, threadFactory);
return cleaner;
}
// 注册一个对象与清理任务,当对象被 GC 回收后,后台线程执行 action。返回 Cleanable 可用于提前清理。
public Cleanable register(Object obj, Runnable action) {
Objects.requireNonNull(obj, "obj");
Objects.requireNonNull(action, "action");
return new CleanerImpl.PhantomCleanableRef(obj, this, action);
}
// 表示一次清理任务,调用 clean() 方法可以手动执行清理逻辑,只会执行一次。
public interface Cleanable {
void clean();
}
}