001/*
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v2.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014
015package ch.qos.logback.core.util;
016
017import ch.qos.logback.core.Context;
018import ch.qos.logback.core.spi.ContextAwareBase;
019
020/**
021 * Allows masking of interrupt flag if previously the flag is already set. Does
022 * nothing otherwise.
023 * 
024 * Typical use:
025 * 
026 * <pre>
027 * InterruptUtil interruptUtil = new InterruptUtil(context);
028 * 
029 * try {
030 *     interruptUtil.maskInterruptFlag();
031 *     someOtherThread.join(delay);
032 * } catch (InterruptedException e) {
033 *     // reachable only if join does not succeed within delay.
034 *     // Without the maskInterruptFlag() call, the join() would have returned
035 *     // immediately
036 *     // had the current thread been interrupted previously, i.e. before entering
037 *     // the above block
038 * } finally {
039 *     interruptUtil.unmaskInterruptFlag();
040 * }
041 * </pre>
042 * 
043 * @author Ceki Gulcu
044 * @since 1.2.2
045 */
046public class InterruptUtil extends ContextAwareBase {
047
048    final boolean previouslyInterrupted;
049
050    public InterruptUtil(Context context) {
051        super();
052        setContext(context);
053        previouslyInterrupted = Thread.currentThread().isInterrupted();
054    }
055
056    public void maskInterruptFlag() {
057        if (previouslyInterrupted) {
058            Thread.interrupted();
059        }
060    }
061
062    public void unmaskInterruptFlag() {
063        if (previouslyInterrupted) {
064            try {
065                Thread.currentThread().interrupt();
066            } catch (SecurityException se) {
067                addError("Failed to interrupt current thread", se);
068            }
069        }
070    }
071
072}