/*
* 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.tomcat.util.collections;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import org.apache.tomcat.util.res.StringManager;
/**
* A Map implementation that uses case-insensitive (using {@link Locale#ENGLISH}) strings as keys.
* <p>
* Keys must be instances of {@link String}. Note that this means that <code>null</code> keys are not permitted.
* <p>
* This implementation is not thread-safe.
*
* @param <V> Type of values placed in this Map.
*/
public class CaseInsensitiveKeyMap<V> extends AbstractMap<String,V> {
private static final StringManager sm = StringManager.getManager(CaseInsensitiveKeyMap.class);
private final Map<Key,V> map = new HashMap<>();
@Override
public V get(Object key) {
return map.get(Key.getInstance(key));
}
@Override
public V put(String key, V value) {
Key caseInsensitiveKey = Key.getInstance(key);
if (caseInsensitiveKey == null) {
throw new NullPointerException(sm.getString("caseInsensitiveKeyMap.nullKey"));
}
return map.put(caseInsensitiveKey, value);
}
/**
* {@inheritDoc}
* <p>
* <b>Use this method with caution</b>. If the input Map contains duplicate keys when the keys are compared in a
* case-insensitive manner then some values will be lost when inserting via this method.
*/
@Override
public void putAll(Map<? extends String,? extends V> m) {
super.putAll(m);
}
@Override
public boolean containsKey(Object key) {
return map.containsKey(Key.getInstance(key));
}
@Override
public V remove(Object key) {
return map.remove(Key.getInstance(key));
}
@Override
public Set<Entry<String,V>> entrySet() {
return new EntrySet<>(map.entrySet());
}
private static class EntrySet<V> extends AbstractSet<Entry<String,V>> {
private final Set<Entry<Key,V>> entrySet;
EntrySet(Set<Map.Entry<Key,V>> entrySet) {
this.entrySet = entrySet;
}
@Override
public Iterator<Entry<String,V>> iterator() {
return new EntryIterator<>(entrySet.iterator());
}
@Override
public int size() {
return entrySet.size();
}
}
private record EntryIterator<V>(Iterator<Entry<Key,V>> iterator) implements Iterator<Entry<String,V>> {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public Entry<String,V> next() {
Entry<Key,V> entry = iterator.next();
return new EntryImpl<>(entry.getKey().getKey(), entry.getValue());
}
@Override
public void remove() {
iterator.remove();
}
}
private record EntryImpl<V>(String key, V value) implements Entry<String,V> {
@Override
public String getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(V value) {
throw new UnsupportedOperationException();
}
}
private static class Key {
private final String key;
private final String lcKey;
private Key(String key) {
this.key = key;
this.lcKey = key.toLowerCase(Locale.ENGLISH);
}
public String getKey() {
return key;
}
@Override
public int hashCode() {
return lcKey.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
Key other = (Key) obj;
return lcKey.equals(other.lcKey);
}
public static Key getInstance(Object o) {
if (o instanceof String) {
return new Key((String) o);
}
return null;
}
}
}