-/*
- * 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.helpers;
-
-import org.apache.log4j.spi.LoggingEvent;
-import org.apache.log4j.pattern.LogEvent;
-
-import java.lang.reflect.Method;
-import java.util.Set;
-import java.io.ByteArrayOutputStream;
-import java.io.ObjectOutputStream;
-import java.io.ByteArrayInputStream;
-import java.io.ObjectInputStream;
-
-
-public final class MDCKeySetExtractor {
- private final Method getKeySetMethod;
- public static final MDCKeySetExtractor INSTANCE =
- new MDCKeySetExtractor();
-
-
- private MDCKeySetExtractor() {
- //
- // log4j 1.2.15 and later will have method to get names
- // of all keys in MDC
- //
- Method getMethod = null;
-
- try {
- getMethod = LoggingEvent.class.getMethod(
- "getPropertyKeySet", null);
- } catch(Exception ex) {
- getMethod = null;
- }
- getKeySetMethod = getMethod;
-
- }
-
- public Set getPropertyKeySet(final LoggingEvent event) throws Exception {
- //
- // MDC keys are not visible prior to log4j 1.2.15
- //
- Set keySet = null;
- if (getKeySetMethod != null) {
- keySet = (Set) getKeySetMethod.invoke(event, null);
- } else {
- //
- // for 1.2.14 and earlier could serialize and
- // extract MDC content
- ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
- ObjectOutputStream os = new ObjectOutputStream(outBytes);
- os.writeObject(event);
- os.close();
-
- byte[] raw = outBytes.toByteArray();
- //
- // bytes 6 and 7 should be the length of the original classname
- // should be the same as our substitute class name
- final String subClassName = LogEvent.class.getName();
- if (raw[6] == 0 || raw[7] == subClassName.length()) {
- //
- // manipulate stream to use our class name
- //
- for (int i = 0; i < subClassName.length(); i++) {
- raw[8 + i] = (byte) subClassName.charAt(i);
- }
- ByteArrayInputStream inBytes = new ByteArrayInputStream(raw);
- ObjectInputStream is = new ObjectInputStream(inBytes);
- Object cracked = is.readObject();
- if (cracked instanceof LogEvent) {
- keySet = ((LogEvent) cracked).getPropertyKeySet();
- }
- is.close();
- }
- }
- return keySet;
- }
-}