聊聊logback的ShutdownHook

序

本文主要研究一下logback的ShutdownHook

ShutdownHook

ch/qos/logback/core/hook/ShutdownHook.java

/**
 * Interface describing a logback shutdown hook implementation
 * 
 * @author Mike Reinhold
 */
public interface ShutdownHook extends Runnable, ContextAware {
}

ShutdownHook接口继承了Runnable、ContextAware接口

ShutdownHookBase

ch/qos/logback/core/hook/ShutdownHookBase.java

/**
 * Base class for classes implementing a Logback ShutdownHook via extension
 *
 * @author Mike Reinhold
 */
public abstract class ShutdownHookBase extends ContextAwareBase implements ShutdownHook {

    public ShutdownHookBase() {
    }

    /**
     * Default method for stopping the Logback context
     */
    protected void stop() {
        addInfo("Logback context being closed via shutdown hook");

        Context hookContext = getContext();
        if (hookContext instanceof ContextBase) {
            ContextBase context = (ContextBase) hookContext;
            context.stop();
        }
    }
}

ShutdownHookBase继承了ContextAwareBase，声明实现ShutdownHook，它提供了一个stop方法，用于关闭ContextBase

DelayingShutdownHook

ch/qos/logback/core/hook/DelayingShutdownHook.java

/**
 * ShutdownHook implementation that stops the Logback context after a specified
 * delay.  The default delay is 0 ms (zero).
 *
 * @author Mike Reinhold
 */
public class DelayingShutdownHook extends ShutdownHookBase {
    /**
     * The default is no delay before shutdown.
     */
    public static final Duration DEFAULT_DELAY = Duration.buildByMilliseconds(0);

    /**
     * The delay in milliseconds before the ShutdownHook stops the logback context
     */
    private Duration delay = DEFAULT_DELAY;

    public DelayingShutdownHook() {
    }

    public Duration getDelay() {
        return delay;
    }

    /**
     * The duration to wait before shutting down the current logback context.
     *
     * @param delay
     */
    public void setDelay(Duration delay) {
        this.delay = delay;
    }

    public void run() {
        addInfo("Sleeping for "+delay);
        try {
            Thread.sleep(delay.getMilliseconds());
        } catch (InterruptedException e) {
        }
        super.stop();
    }
}

DelayingShutdownHook继承了ShutdownHookBase，其run方法先sleep指定的delay，然后执行stop方法

示例

    
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小结

logback的ShutdownHook接口继承了Runnable、ContextAware接口，它有一个抽象类ShutdownHookBase提供了一个stop方法，用于关闭ContextBase，它的子类为DelayingShutdownHook，可以延迟指定时间再关闭ContextBase。