+++ /dev/null
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.log4j;
-
-import org.apache.log4j.helpers.Loader;
-import org.apache.log4j.helpers.ThreadLocalMap;
-
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.util.Hashtable;
-
-/**
- * The MDC class is similar to the {@link NDC} class except that it is
- * based on a map instead of a stack. It provides <em>mapped
- * diagnostic contexts</em>. A <em>Mapped Diagnostic Context</em>, or
- * MDC in short, is an instrument for distinguishing interleaved log
- * output from different sources. Log output is typically interleaved
- * when a server handles multiple clients near-simultaneously.
- * <p/>
- * <p><b><em>The MDC is managed on a per thread basis</em></b>. A
- * child thread automatically inherits a <em>copy</em> of the mapped
- * diagnostic context of its parent.
- * <p/>
- * <p>The MDC class requires JDK 1.2 or above. Under JDK 1.1 the MDC
- * will always return empty values but otherwise will not affect or
- * harm your application.</p>
- *
- * <p>Attention: the application is required to clean up. In web applications
- * this can happen with creating a Servlet Filter and overriding the
- * onFilter method like:</p>
- *
- * <pre>
- * try {
- * MDC.put(myKey);
- * chain.doFilter(request, response);
- * } finally {
- * MDC.remove(myKey);
- * }
- * </pre>
- *
- * <p>Please also see: {@link http://logging.apache.org/log4j/1.2/faq.html#mdcmemoryleak}</p>
- *
- * @author Ceki Gülcü
- * @since 1.2
- */
-public class MDC {
-
- final static MDC mdc = new MDC();
-
- static final int HT_SIZE = 7;
-
- boolean java1;
-
- Object tlm;
-
- private Method removeMethod;
-
- private MDC() {
- java1 = Loader.isJava1();
- if (!java1) {
- tlm = new ThreadLocalMap();
- }
-
- try {
- removeMethod = ThreadLocal.class.getMethod("remove", null);
- } catch (NoSuchMethodException e) {
- // don't do anything - java prior 1.5
- }
- }
-
- /**
- * Put a context value (the <code>o</code> parameter) as identified
- * with the <code>key</code> parameter into the current thread's
- * context map.
- * <p/>
- * <p>If the current thread does not have a context map it is
- * created as a side effect.
- */
- public static void put(String key, Object o) {
- if (mdc != null) {
- mdc.put0(key, o);
- }
- }
-
- /**
- * Get the context identified by the <code>key</code> parameter.
- * <p/>
- * <p>This method has no side effects.
- */
- public static Object get(String key) {
- if (mdc != null) {
- return mdc.get0(key);
- }
- return null;
- }
-
- /**
- * Remove the the context identified by the <code>key</code>
- * parameter.
- */
- public static void remove(String key) {
- if (mdc != null) {
- mdc.remove0(key);
- }
- }
-
-
- /**
- * Get the current thread's MDC as a hashtable. This method is
- * intended to be used internally.
- */
- public static Hashtable getContext() {
- if (mdc != null) {
- return mdc.getContext0();
- } else {
- return null;
- }
- }
-
- /**
- * Remove all values from the MDC.
- *
- * @since 1.2.16
- */
- public static void clear() {
- if (mdc != null) {
- mdc.clear0();
- }
- }
-
-
- private void put0(String key, Object o) {
- if (java1 || tlm == null) {
- return;
- } else {
- Hashtable ht = (Hashtable) ((ThreadLocalMap) tlm).get();
- if (ht == null) {
- ht = new Hashtable(HT_SIZE);
- ((ThreadLocalMap) tlm).set(ht);
- }
- ht.put(key, o);
- }
- }
-
- private Object get0(String key) {
- if (java1 || tlm == null) {
- return null;
- } else {
- Hashtable ht = (Hashtable) ((ThreadLocalMap) tlm).get();
- if (ht != null && key != null) {
- return ht.get(key);
- } else {
- return null;
- }
- }
- }
-
- private void remove0(String key) {
- if (!java1 && tlm != null) {
- Hashtable ht = (Hashtable) ((ThreadLocalMap) tlm).get();
- if (ht != null) {
- ht.remove(key);
- // clean up if this was the last key
- if (ht.isEmpty()) {
- clear0();
- }
- }
- }
- }
-
- private Hashtable getContext0() {
- if (java1 || tlm == null) {
- return null;
- } else {
- return (Hashtable) ((ThreadLocalMap) tlm).get();
- }
- }
-
- private void clear0() {
- if (!java1 && tlm != null) {
- Hashtable ht = (Hashtable) ((ThreadLocalMap) tlm).get();
- if (ht != null) {
- ht.clear();
- }
- if (removeMethod != null) {
- // java 1.3/1.4 does not have remove - will suffer from a memory leak
- try {
- removeMethod.invoke(tlm, null);
- } catch (IllegalAccessException e) {
- // should not happen
- } catch (InvocationTargetException e) {
- // should not happen
- }
- }
- }
- }
-}
git://source.jalview.org / jalview.git / blobdiff