org.apache.logging.log4j.core.impl.JdkMapAdapterStringMap Maven / Gradle / Ivy
/*
* 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.core.impl;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.WeakHashMap;
import org.apache.logging.log4j.util.BiConsumer;
import org.apache.logging.log4j.util.ReadOnlyStringMap;
import org.apache.logging.log4j.util.StringMap;
import org.apache.logging.log4j.util.Strings;
import org.apache.logging.log4j.util.TriConsumer;
/**
* Provides a read-only {@code StringMap} view of a {@code Map}.
*/
public class JdkMapAdapterStringMap implements StringMap {
private static final long serialVersionUID = -7348247784983193612L;
private static final String FROZEN = "Frozen collection cannot be modified";
private static final Comparator NULL_FIRST_COMPARATOR = (left, right) -> {
if (left == null) {
return -1;
}
if (right == null) {
return 1;
}
return left.compareTo(right);
};
// Cache of known unmodifiable map implementations.
// It is a cache, no need to synchronise it between threads.
private static Map, Void> UNMODIFIABLE_MAPS_CACHE = new WeakHashMap<>();
private final Map map;
private boolean immutable = false;
private transient String[] sortedKeys;
public JdkMapAdapterStringMap() {
this(new HashMap<>(), false);
}
/**
* @deprecated for performance reasons since 2.23.
* Use {@link #JdkMapAdapterStringMap(Map, boolean)} instead.
*/
@Deprecated
public JdkMapAdapterStringMap(final Map map) {
this.map = Objects.requireNonNull(map, "map");
// Known immutable implementations
if (UNMODIFIABLE_MAPS_CACHE.containsKey(map.getClass())) {
immutable = true;
} else {
// Check with a NO-OP replacement
try {
map.replace(Strings.EMPTY, Strings.EMPTY, Strings.EMPTY);
} catch (final UnsupportedOperationException ignored) {
final WeakHashMap, Void> cache = new WeakHashMap<>(UNMODIFIABLE_MAPS_CACHE);
cache.put(map.getClass(), null);
UNMODIFIABLE_MAPS_CACHE = cache;
immutable = true;
}
}
}
/**
* Constructs a new {@link StringMap}, based on a JDK map.
*
* The underlying map should not be modified after this call.
*
*
* If the {@link Map} implementation does not allow modifications, {@code frozen} should be set to {@code true}.
*
* @param map a JDK map,
* @param frozen if {@code true} this collection will be immutable.
*/
public JdkMapAdapterStringMap(final Map map, final boolean frozen) {
this.map = Objects.requireNonNull(map, "map");
this.immutable = frozen;
}
@Override
public Map toMap() {
return new HashMap<>(map);
}
private void assertNotFrozen() {
if (immutable) {
throw new UnsupportedOperationException(FROZEN);
}
}
@Override
public boolean containsKey(final String key) {
return map.containsKey(key);
}
@SuppressWarnings("unchecked")
@Override
public void forEach(final BiConsumer action) {
final String[] keys = getSortedKeys();
for (int i = 0; i < keys.length; i++) {
action.accept(keys[i], (V) map.get(keys[i]));
}
}
@SuppressWarnings("unchecked")
@Override
public void forEach(final TriConsumer action, final S state) {
final String[] keys = getSortedKeys();
for (int i = 0; i < keys.length; i++) {
action.accept(keys[i], (V) map.get(keys[i]), state);
}
}
private String[] getSortedKeys() {
if (sortedKeys == null) {
sortedKeys = map.keySet().toArray(Strings.EMPTY_ARRAY);
Arrays.sort(sortedKeys, NULL_FIRST_COMPARATOR);
}
return sortedKeys;
}
@SuppressWarnings("unchecked")
@Override
public V getValue(final String key) {
return (V) map.get(key);
}
@Override
public boolean isEmpty() {
return map.isEmpty();
}
@Override
public int size() {
return map.size();
}
@Override
public void clear() {
if (map.isEmpty()) {
return;
}
assertNotFrozen();
map.clear();
sortedKeys = null;
}
@Override
public void freeze() {
immutable = true;
}
@Override
public boolean isFrozen() {
return immutable;
}
@Override
public void putAll(final ReadOnlyStringMap source) {
assertNotFrozen();
source.forEach(PUT_ALL, map);
sortedKeys = null;
}
private static TriConsumer> PUT_ALL =
(key, value, stringStringMap) -> stringStringMap.put(key, value);
@Override
public void putValue(final String key, final Object value) {
assertNotFrozen();
map.put(key, value == null ? null : String.valueOf(value));
sortedKeys = null;
}
@Override
public void remove(final String key) {
if (!map.containsKey(key)) {
return;
}
assertNotFrozen();
map.remove(key);
sortedKeys = null;
}
@Override
public String toString() {
final StringBuilder result = new StringBuilder(map.size() * 13);
result.append('{');
final String[] keys = getSortedKeys();
for (int i = 0; i < keys.length; i++) {
if (i > 0) {
result.append(", ");
}
result.append(keys[i]).append('=').append(map.get(keys[i]));
}
result.append('}');
return result.toString();
}
@Override
public boolean equals(final Object object) {
if (object == this) {
return true;
}
if (!(object instanceof JdkMapAdapterStringMap)) {
return false;
}
final JdkMapAdapterStringMap other = (JdkMapAdapterStringMap) object;
return map.equals(other.map) && immutable == other.immutable;
}
@Override
public int hashCode() {
return map.hashCode() + (immutable ? 31 : 0);
}
}