/*
* 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.logging.log4j;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* Adds entries to the {@link ThreadContext stack or map} and them removes them when the object is closed, e.g. as part
* of a try-with-resources. User code can now look like this:
* <pre>
* try (final CloseableThreadContext.Instance ignored = CloseableThreadContext.put(key1, value1).put(key2, value2)) {
* callSomeMethodThatLogsALot();
*
* // Entries for key1 and key2 are automatically removed from the ThreadContext map when done.
* }
* </pre>
*
* @since 2.6
*/
public class CloseableThreadContext {
private CloseableThreadContext() {
}
/**
* Pushes new diagnostic context information on to the Thread Context Stack. The information will be popped off when
* the instance is closed.
*
* @param message The new diagnostic context information.
* @return a new instance that will back out the changes when closed.
*/
public static CloseableThreadContext.Instance push(final String message) {
return new CloseableThreadContext.Instance().push(message);
}
/**
* Pushes new diagnostic context information on to the Thread Context Stack. The information will be popped off when
* the instance is closed.
*
* @param message The new diagnostic context information.
* @param args Parameters for the message.
* @return a new instance that will back out the changes when closed.
*/
public static CloseableThreadContext.Instance push(final String message, final Object... args) {
return new CloseableThreadContext.Instance().push(message, args);
}
/**
* Populates the Thread Context Map with the supplied key/value pair. Any existing key in the
* {@link ThreadContext} will be replaced with the supplied value, and restored back to their original value when
* the instance is closed.
*
* @param key The key to be added
* @param value The value to be added
* @return a new instance that will back out the changes when closed.
*/
public static CloseableThreadContext.Instance put(final String key, final String value) {
return new CloseableThreadContext.Instance().put(key, value);
}
/**
* Populates the Thread Context Stack with the supplied stack. The information will be popped off when
* the instance is closed.
*
* @param messages The list of messages to be added
* @return a new instance that will back out the changes when closed.
* @since 2.8
*/
public static CloseableThreadContext.Instance pushAll(final List<String> messages) {
return new CloseableThreadContext.Instance().pushAll(messages);
}
/**
* Populates the Thread Context Map with the supplied key/value pairs. Any existing keys in the
* {@link ThreadContext} will be replaced with the supplied values, and restored back to their original value when
* the instance is closed.
*
* @param values The map of key/value pairs to be added
* @return a new instance that will back out the changes when closed.
* @since 2.8
*/
public static CloseableThreadContext.Instance putAll(final Map<String, String> values) {
return new CloseableThreadContext.Instance().putAll(values);
}
public static class Instance implements AutoCloseable {
private int pushCount = 0;
private final Map<String, String> originalValues = new HashMap<>();
private Instance() {
}
/**
* Pushes new diagnostic context information on to the Thread Context Stack. The information will be popped off when
* the instance is closed.
*
* @param message The new diagnostic context information.
* @return the instance that will back out the changes when closed.
*/
public Instance push(final String message) {
ThreadContext.push(message);
pushCount++;
return this;
}
/**
* Pushes new diagnostic context information on to the Thread Context Stack. The information will be popped off when
* the instance is closed.
*
* @param message The new diagnostic context information.
* @param args Parameters for the message.
* @return the instance that will back out the changes when closed.
*/
public Instance push(final String message, final Object[] args) {
ThreadContext.push(message, args);
pushCount++;
return this;
}
/**
* Populates the Thread Context Map with the supplied key/value pair. Any existing key in the
* {@link ThreadContext} will be replaced with the supplied value, and restored back to their original value when
* the instance is closed.
*
* @param key The key to be added
* @param value The value to be added
* @return a new instance that will back out the changes when closed.
*/
public Instance put(final String key, final String value) {
// If there are no existing values, a null will be stored as an old value
if (!originalValues.containsKey(key)) {
originalValues.put(key, ThreadContext.get(key));
}
ThreadContext.put(key, value);
return this;
}
/**
* Populates the Thread Context Map with the supplied key/value pairs. Any existing keys in the
* {@link ThreadContext} will be replaced with the supplied values, and restored back to their original value when
* the instance is closed.
*
* @param values The map of key/value pairs to be added
* @return a new instance that will back out the changes when closed.
* @since 2.8
*/
public Instance putAll(final Map<String, String> values) {
final Map<String, String> currentValues = ThreadContext.getContext();
ThreadContext.putAll(values);
for (final String key : values.keySet()) {
if (!originalValues.containsKey(key)) {
originalValues.put(key, currentValues.get(key));
}
}
return this;
}
/**
* Populates the Thread Context Stack with the supplied stack. The information will be popped off when
* the instance is closed.
*
* @param messages The list of messages to be added
* @return a new instance that will back out the changes when closed.
* @since 2.8
*/
public Instance pushAll(final List<String> messages) {
for (final String message : messages) {
push(message);
}
return this;
}
/**
* Removes the values from the {@link ThreadContext}.
* <p>
* Values pushed to the {@link ThreadContext} <em>stack</em> will be popped off.
* </p>
* <p>
* Values put on the {@link ThreadContext} <em>map</em> will be removed, or restored to their original values it they already existed.
* </p>
*/
@Override
public void close() {
closeStack();
closeMap();
}
private void closeMap() {
for (final Iterator<Map.Entry<String, String>> it = originalValues.entrySet().iterator(); it.hasNext(); ) {
final Map.Entry<String, String> entry = it.next();
final String key = entry.getKey();
final String originalValue = entry.getValue();
if (null == originalValue) {
ThreadContext.remove(key);
} else {
ThreadContext.put(key, originalValue);
}
it.remove();
}
}
private void closeStack() {
for (int i = 0; i < pushCount; i++) {
ThreadContext.pop();
}
pushCount = 0;
}
}
}