001/** 002 * Logback: the reliable, generic, fast and flexible logging framework. 003 * Copyright (C) 1999-2015, 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 v1.0 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 */ 014package ch.qos.logback.classic.util; 015 016import java.util.HashMap; 017 018/** 019 * This class extends InheritableThreadLocal so that children threads get a copy 020 * of the parent's hashmap. 021 * 022 * @author Ceki Gülcü 023 */ 024public class CopyOnInheritThreadLocal extends InheritableThreadLocal<HashMap<String, String>> { 025 026 /** 027 * Child threads should get a copy of the parent's hashmap. 028 */ 029 @Override 030 protected HashMap<String, String> childValue(HashMap<String, String> parentValue) { 031 if (parentValue == null) { 032 return null; 033 } else { 034 return new HashMap<String, String>(parentValue); 035 } 036 } 037 038}