log4j-api/src/main/java/org/apache/logging/log4j/spi/CopyOnWriteSortedArrayThreadContextMap.java - logging-log4j2 - Git at Google

 /*
  * 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.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;

 import org.apache.logging.log4j.util.ReadOnlyStringMap;
 import org.apache.logging.log4j.util.SortedArrayStringMap;
 import org.apache.logging.log4j.util.StringMap;
 import org.apache.logging.log4j.util.PropertiesUtil;

 /**
  * {@code SortedArrayStringMap}-based implementation of the {@code ThreadContextMap} interface that creates a copy of
  * the data structure on every modification. Any particular instance of the data structure is a snapshot of the
  * ThreadContext at some point in time and can safely be passed off to other threads.  Since it is
  * expected that the Map will be passed to many more log events than the number of keys it contains the performance
  * should be much better than if the Map was copied for each event.
  *
  * @since 2.7
  */
 class CopyOnWriteSortedArrayThreadContextMap implements ReadOnlyThreadContextMap, ObjectThreadContextMap, CopyOnWrite {

     /**
      * Property name ({@value} ) for selecting {@code InheritableThreadLocal} (value "true") or plain
      * {@code ThreadLocal} (value is not "true") in the implementation.
      */
     public static final String INHERITABLE_MAP = "isThreadContextMapInheritable";

     /**
      * The default initial capacity.
      */
     protected static final int DEFAULT_INITIAL_CAPACITY = 16;

     /**
      * System property name that can be used to control the data structure's initial capacity.
      */
     protected static final String PROPERTY_NAME_INITIAL_CAPACITY = "log4j2.ThreadContext.initial.capacity";

     private static final StringMap EMPTY_CONTEXT_DATA = new SortedArrayStringMap(1);

     private static volatile int initialCapacity;
     private static volatile boolean inheritableMap;

     /**
      * Initializes static variables based on system properties. Normally called when this class is initialized by the VM
      * and when Log4j is reconfigured.
      */
     static void init() {
         final PropertiesUtil properties = PropertiesUtil.getProperties();
         initialCapacity = properties.getIntegerProperty(PROPERTY_NAME_INITIAL_CAPACITY, DEFAULT_INITIAL_CAPACITY);
         inheritableMap = properties.getBooleanProperty(INHERITABLE_MAP);
     }

     static {
         EMPTY_CONTEXT_DATA.freeze();
         init();
     }

     private final ThreadLocal<StringMap> localMap;

     public CopyOnWriteSortedArrayThreadContextMap() {
         this.localMap = createThreadLocalMap();
     }

     // LOG4J2-479: by default, use a plain ThreadLocal, only use InheritableThreadLocal if configured.
     // (This method is package protected for JUnit tests.)
     private ThreadLocal<StringMap> createThreadLocalMap() {
         if (inheritableMap) {
             return new InheritableThreadLocal<StringMap>() {
                 @Override
                 protected StringMap childValue(final StringMap parentValue) {
                     if (parentValue == null) {
                         return null;
                     }
                     final StringMap stringMap = createStringMap(parentValue);
                     stringMap.freeze();
                     return stringMap;
                 }
             };
         }
         // if not inheritable, return plain ThreadLocal with null as initial value
         return new ThreadLocal<>();
     }

     /**
      * Returns an implementation of the {@code StringMap} used to back this thread context map.
      * <p>
      * Subclasses may override.
      * </p>
      * @return an implementation of the {@code StringMap} used to back this thread context map
      */
     protected StringMap createStringMap() {
         return new SortedArrayStringMap(initialCapacity);
     }

     /**
      * Returns an implementation of the {@code StringMap} used to back this thread context map, pre-populated
      * with the contents of the specified context data.
      * <p>
      * Subclasses may override.
      * </p>
      * @param original the key-value pairs to initialize the returned context data with
      * @return an implementation of the {@code StringMap} used to back this thread context map
      */
     protected StringMap createStringMap(final ReadOnlyStringMap original) {
         return new SortedArrayStringMap(original);
     }

     @Override
     public void put(final String key, final String value) {
         putValue(key, value);
     }

     @Override
     public void putValue(final String key, final Object value) {
         StringMap map = localMap.get();
         map = map == null ? createStringMap() : createStringMap(map);
         map.putValue(key, value);
         map.freeze();
         localMap.set(map);
     }

     @Override
     public void putAll(final Map<String, String> values) {
         if (values == null || values.isEmpty()) {
             return;
         }
         StringMap map = localMap.get();
         map = map == null ? createStringMap() : createStringMap(map);
         for (final Map.Entry<String, String> entry : values.entrySet()) {
             map.putValue(entry.getKey(), entry.getValue());
         }
         map.freeze();
         localMap.set(map);
     }

     @Override
     public <V> void putAllValues(final Map<String, V> values) {
         if (values == null || values.isEmpty()) {
             return;
         }
         StringMap map = localMap.get();
         map = map == null ? createStringMap() : createStringMap(map);
         for (final Map.Entry<String, V> entry : values.entrySet()) {
             map.putValue(entry.getKey(), entry.getValue());
         }
         map.freeze();
         localMap.set(map);
     }

     @Override
     public String get(final String key) {
         return (String) getValue(key);
     }

     @Override
     public <V> V getValue(final String key) {
         final StringMap map = localMap.get();
         return map == null ? null : map.<V>getValue(key);
     }

     @Override
     public void remove(final String key) {
         final StringMap map = localMap.get();
         if (map != null) {
             final StringMap copy = createStringMap(map);
             copy.remove(key);
             copy.freeze();
             localMap.set(copy);
         }
     }

     @Override
     public void removeAll(final Iterable<String> keys) {
         final StringMap map = localMap.get();
         if (map != null) {
             final StringMap copy = createStringMap(map);
             for (final String key : keys) {
                 copy.remove(key);
             }
             copy.freeze();
             localMap.set(copy);
         }
     }

     @Override
     public void clear() {
         localMap.remove();
     }

     @Override
     public boolean containsKey(final String key) {
         final StringMap map = localMap.get();
         return map != null && map.containsKey(key);
     }

     @Override
     public Map<String, String> getCopy() {
         final StringMap map = localMap.get();
         return map == null ? new HashMap<String, String>() : map.toMap();
     }

     /**
      * {@inheritDoc}
      */
     @Override
     public StringMap getReadOnlyContextData() {
         final StringMap map = localMap.get();
         return map == null ? EMPTY_CONTEXT_DATA : map;
     }

     @Override
     public Map<String, String> getImmutableMapOrNull() {
         final StringMap map = localMap.get();
         return map == null ? null : Collections.unmodifiableMap(map.toMap());
     }

     @Override
     public boolean isEmpty() {
         final StringMap map = localMap.get();
         return map == null || map.size() == 0;
     }

     @Override
     public String toString() {
         final StringMap map = localMap.get();
         return map == null ? "{}" : map.toString();
     }

     @Override
     public int hashCode() {
         final int prime = 31;
         int result = 1;
         final StringMap map = this.localMap.get();
         result = prime * result + ((map == null) ? 0 : map.hashCode());
         return result;
     }

     @Override
     public boolean equals(final Object obj) {
         if (this == obj) {
             return true;
         }
         if (obj == null) {
             return false;
         }
         if (!(obj instanceof ThreadContextMap)) {
             return false;
         }
         final ThreadContextMap other = (ThreadContextMap) obj;
         final Map<String, String> map = this.getImmutableMapOrNull();
         final Map<String, String> otherMap = other.getImmutableMapOrNull();
         return Objects.equals(map, otherMap);
     }
 }
	/*
	* 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.Collections;
	import java.util.HashMap;
	import java.util.Map;
	import java.util.Objects;

	import org.apache.logging.log4j.util.ReadOnlyStringMap;
	import org.apache.logging.log4j.util.SortedArrayStringMap;
	import org.apache.logging.log4j.util.StringMap;
	import org.apache.logging.log4j.util.PropertiesUtil;

	/**
	* {@code SortedArrayStringMap}-based implementation of the {@code ThreadContextMap} interface that creates a copy of
	* the data structure on every modification. Any particular instance of the data structure is a snapshot of the
	* ThreadContext at some point in time and can safely be passed off to other threads. Since it is
	* expected that the Map will be passed to many more log events than the number of keys it contains the performance
	* should be much better than if the Map was copied for each event.
	*
	* @since 2.7
	*/
	class CopyOnWriteSortedArrayThreadContextMap implements ReadOnlyThreadContextMap, ObjectThreadContextMap, CopyOnWrite {

	/**
	* Property name ({@value} ) for selecting {@code InheritableThreadLocal} (value "true") or plain
	* {@code ThreadLocal} (value is not "true") in the implementation.
	*/
	public static final String INHERITABLE_MAP = "isThreadContextMapInheritable";

	/**
	* The default initial capacity.
	*/
	protected static final int DEFAULT_INITIAL_CAPACITY = 16;

	/**
	* System property name that can be used to control the data structure's initial capacity.
	*/
	protected static final String PROPERTY_NAME_INITIAL_CAPACITY = "log4j2.ThreadContext.initial.capacity";

	private static final StringMap EMPTY_CONTEXT_DATA = new SortedArrayStringMap(1);

	private static volatile int initialCapacity;
	private static volatile boolean inheritableMap;

	/**
	* Initializes static variables based on system properties. Normally called when this class is initialized by the VM
	* and when Log4j is reconfigured.
	*/
	static void init() {
	final PropertiesUtil properties = PropertiesUtil.getProperties();
	initialCapacity = properties.getIntegerProperty(PROPERTY_NAME_INITIAL_CAPACITY, DEFAULT_INITIAL_CAPACITY);
	inheritableMap = properties.getBooleanProperty(INHERITABLE_MAP);
	}

	static {
	EMPTY_CONTEXT_DATA.freeze();
	init();
	}

	private final ThreadLocal<StringMap> localMap;

	public CopyOnWriteSortedArrayThreadContextMap() {
	this.localMap = createThreadLocalMap();
	}

	// LOG4J2-479: by default, use a plain ThreadLocal, only use InheritableThreadLocal if configured.
	// (This method is package protected for JUnit tests.)
	private ThreadLocal<StringMap> createThreadLocalMap() {
	if (inheritableMap) {
	return new InheritableThreadLocal<StringMap>() {
	@Override
	protected StringMap childValue(final StringMap parentValue) {
	if (parentValue == null) {
	return null;
	}
	final StringMap stringMap = createStringMap(parentValue);
	stringMap.freeze();
	return stringMap;
	}
	};
	}
	// if not inheritable, return plain ThreadLocal with null as initial value
	return new ThreadLocal<>();
	}

	/**
	* Returns an implementation of the {@code StringMap} used to back this thread context map.
	* <p>
	* Subclasses may override.
	* </p>
	* @return an implementation of the {@code StringMap} used to back this thread context map
	*/
	protected StringMap createStringMap() {
	return new SortedArrayStringMap(initialCapacity);
	}

	/**
	* Returns an implementation of the {@code StringMap} used to back this thread context map, pre-populated
	* with the contents of the specified context data.
	* <p>
	* Subclasses may override.
	* </p>
	* @param original the key-value pairs to initialize the returned context data with
	* @return an implementation of the {@code StringMap} used to back this thread context map
	*/
	protected StringMap createStringMap(final ReadOnlyStringMap original) {
	return new SortedArrayStringMap(original);
	}

	@Override
	public void put(final String key, final String value) {
	putValue(key, value);
	}

	@Override
	public void putValue(final String key, final Object value) {
	StringMap map = localMap.get();
	map = map == null ? createStringMap() : createStringMap(map);
	map.putValue(key, value);
	map.freeze();
	localMap.set(map);
	}

	@Override
	public void putAll(final Map<String, String> values) {
	if (values == null \|\| values.isEmpty()) {
	return;
	}
	StringMap map = localMap.get();
	map = map == null ? createStringMap() : createStringMap(map);
	for (final Map.Entry<String, String> entry : values.entrySet()) {
	map.putValue(entry.getKey(), entry.getValue());
	}
	map.freeze();
	localMap.set(map);
	}

	@Override
	public <V> void putAllValues(final Map<String, V> values) {
	if (values == null \|\| values.isEmpty()) {
	return;
	}
	StringMap map = localMap.get();
	map = map == null ? createStringMap() : createStringMap(map);
	for (final Map.Entry<String, V> entry : values.entrySet()) {
	map.putValue(entry.getKey(), entry.getValue());
	}
	map.freeze();
	localMap.set(map);
	}

	@Override
	public String get(final String key) {
	return (String) getValue(key);
	}

	@Override
	public <V> V getValue(final String key) {
	final StringMap map = localMap.get();
	return map == null ? null : map.<V>getValue(key);
	}

	@Override
	public void remove(final String key) {
	final StringMap map = localMap.get();
	if (map != null) {
	final StringMap copy = createStringMap(map);
	copy.remove(key);
	copy.freeze();
	localMap.set(copy);
	}
	}

	@Override
	public void removeAll(final Iterable<String> keys) {
	final StringMap map = localMap.get();
	if (map != null) {
	final StringMap copy = createStringMap(map);
	for (final String key : keys) {
	copy.remove(key);
	}
	copy.freeze();
	localMap.set(copy);
	}
	}

	@Override
	public void clear() {
	localMap.remove();
	}

	@Override
	public boolean containsKey(final String key) {
	final StringMap map = localMap.get();
	return map != null && map.containsKey(key);
	}

	@Override
	public Map<String, String> getCopy() {
	final StringMap map = localMap.get();
	return map == null ? new HashMap<String, String>() : map.toMap();
	}

	/**
	* {@inheritDoc}
	*/
	@Override
	public StringMap getReadOnlyContextData() {
	final StringMap map = localMap.get();
	return map == null ? EMPTY_CONTEXT_DATA : map;
	}

	@Override
	public Map<String, String> getImmutableMapOrNull() {
	final StringMap map = localMap.get();
	return map == null ? null : Collections.unmodifiableMap(map.toMap());
	}

	@Override
	public boolean isEmpty() {
	final StringMap map = localMap.get();
	return map == null \|\| map.size() == 0;
	}

	@Override
	public String toString() {
	final StringMap map = localMap.get();
	return map == null ? "{}" : map.toString();
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	final StringMap map = this.localMap.get();
	result = prime * result + ((map == null) ? 0 : map.hashCode());
	return result;
	}

	@Override
	public boolean equals(final Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj == null) {
	return false;
	}
	if (!(obj instanceof ThreadContextMap)) {
	return false;
	}
	final ThreadContextMap other = (ThreadContextMap) obj;
	final Map<String, String> map = this.getImmutableMapOrNull();
	final Map<String, String> otherMap = other.getImmutableMapOrNull();
	return Objects.equals(map, otherMap);
	}
	}