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/*
* 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.spi;
import java.util.Map;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.util.Cast;
import org.apache.logging.log4j.util.SortedArrayStringMap;
import org.apache.logging.log4j.util.StringMap;
/**
* Service provider interface to implement custom MDC behavior for {@link org.apache.logging.log4j.ThreadContext}.
*
* Since 2.8, {@code ThreadContextMap} implementations that implement the {@link ReadOnlyThreadContextMap} interface
* are accessible to applications via the {@link ThreadContext#getThreadContextMap()} method.
*
*
* Since 3.0.0, {@code ThreadContextMap} combines all its extension interfaces into default methods on this interface.
*
*/
public interface ThreadContextMap {
/**
* Clears the context.
*/
void clear();
/**
* Determines if the key is in the context.
* @param key The key to locate.
* @return True if the key is in the context, false otherwise.
*/
boolean containsKey(final String key);
/**
* Gets the context identified by the key parameter.
*
* This method has no side effects.
* @param key The key to locate.
* @return The value associated with the key or null.
*/
String get(final String key);
/**
* Gets a non-{@code null} mutable copy of current thread's context Map.
* @return a mutable copy of the context.
*/
Map getCopy();
/**
* Returns an immutable view on the context Map or {@code null} if the context map is empty.
* @return an immutable context Map or {@code null}.
*/
Map getImmutableMapOrNull();
/**
* Returns true if the Map is empty.
* @return true if the Map is empty, false otherwise.
*/
boolean isEmpty();
/**
* Puts a context value (the o parameter) as identified
* with the key parameter into the current thread's
* context map.
*
* If the current thread does not have a context map it is
* created as a side effect.
* @param key The key name.
* @param value The key value.
*/
void put(final String key, final String value);
/**
* Removes the context identified by the key
* parameter.
* @param key The key to remove.
*/
void remove(final String key);
/**
* Puts all given context map entries into the current thread's
* context map.
*
* If the current thread does not have a context map it is
* created as a side effect.
* @param map The map.
* @since 3.0.0
*/
default void putAll(Map map) {
map.forEach(this::put);
}
/**
* Returns the context data for reading. Note that regardless of whether the returned context data has been
* {@linkplain StringMap#freeze() frozen} (made read-only) or not, callers should not attempt to modify
* the returned data structure.
*
* @return the {@code StringMap}
* @since 3.0.0
*/
default StringMap getReadOnlyContextData() {
if (this instanceof ReadOnlyThreadContextMap) {
return ((ReadOnlyThreadContextMap) this).getReadOnlyContextData();
}
final Map copy = getCopy();
final StringMap map = new SortedArrayStringMap(copy.size());
copy.forEach(map::putValue);
map.freeze();
return map;
}
/**
* Removes all given context map keys from the current thread's context map.
*
* If the current thread does not have a context map it is
* created as a side effect.
*
* @param keys The keys.
* @since 3.0.0
*/
default void removeAll(Iterable keys) {
keys.forEach(this::remove);
}
/**
* Returns the Object value for the specified key, or {@code null} if the specified key does not exist in this
* collection.
*
* @param key the key whose value to return
* @param The type of the returned value.
* @return the value for the specified key or {@code null}
* @since 3.0.0
*/
default V getValue(String key) {
return Cast.cast(get(key));
}
/**
* Puts the specified key-value pair into the collection.
*
* @param key the key to add or remove. Keys may be {@code null}.
* @param The type of the stored and returned value.
* @param value the value to add. Values may be {@code null}.
* @since 3.0.0
*/
default void putValue(String key, V value) {
put(key, value != null ? value.toString() : null);
}
/**
* Puts all given key-value pairs into the collection.
*
* @param values the map of key-value pairs to add
* @param The type of the value being added.
* @since 3.0.0
*/
default void putAllValues(Map values) {
values.forEach(this::putValue);
}
}