org.springframework.util.LinkedCaseInsensitiveMap Maven / Gradle / Ivy
/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed 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.springframework.util;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
/**
* {@link LinkedHashMap} variant that stores String keys in a case-insensitive
* manner, for example for key-based access in a results table.
*
* Preserves the original order as well as the original casing of keys,
* while allowing for contains, get and remove calls with any case of key.
*
*
Does not support {@code null} keys.
*
* @author Juergen Hoeller
* @since 3.0
*/
@SuppressWarnings("serial")
public class LinkedCaseInsensitiveMap extends LinkedHashMap {
private final Map caseInsensitiveKeys;
private final Locale locale;
/**
* Create a new LinkedCaseInsensitiveMap for the default Locale.
* @see java.lang.String#toLowerCase()
*/
public LinkedCaseInsensitiveMap() {
this(null);
}
/**
* Create a new LinkedCaseInsensitiveMap that stores lower-case keys
* according to the given Locale.
* @param locale the Locale to use for lower-case conversion
* @see java.lang.String#toLowerCase(java.util.Locale)
*/
public LinkedCaseInsensitiveMap(Locale locale) {
super();
this.caseInsensitiveKeys = new HashMap();
this.locale = (locale != null ? locale : Locale.getDefault());
}
/**
* Create a new LinkedCaseInsensitiveMap that wraps a {@link LinkedHashMap}
* with the given initial capacity and stores lower-case keys according
* to the default Locale.
* @param initialCapacity the initial capacity
* @see java.lang.String#toLowerCase()
*/
public LinkedCaseInsensitiveMap(int initialCapacity) {
this(initialCapacity, null);
}
/**
* Create a new LinkedCaseInsensitiveMap that wraps a {@link LinkedHashMap}
* with the given initial capacity and stores lower-case keys according
* to the given Locale.
* @param initialCapacity the initial capacity
* @param locale the Locale to use for lower-case conversion
* @see java.lang.String#toLowerCase(java.util.Locale)
*/
public LinkedCaseInsensitiveMap(int initialCapacity, Locale locale) {
super(initialCapacity);
this.caseInsensitiveKeys = new HashMap(initialCapacity);
this.locale = (locale != null ? locale : Locale.getDefault());
}
@Override
public V put(String key, V value) {
String oldKey = this.caseInsensitiveKeys.put(convertKey(key), key);
if (oldKey != null && !oldKey.equals(key)) {
super.remove(oldKey);
}
return super.put(key, value);
}
@Override
public void putAll(Map map) {
if (map.isEmpty()) {
return;
}
for (Map.Entry entry : map.entrySet()) {
put(entry.getKey(), entry.getValue());
}
}
@Override
public boolean containsKey(Object key) {
return (key instanceof String && this.caseInsensitiveKeys.containsKey(convertKey((String) key)));
}
@Override
public V get(Object key) {
if (key instanceof String) {
return super.get(this.caseInsensitiveKeys.get(convertKey((String) key)));
}
else {
return null;
}
}
@Override
public V remove(Object key) {
if (key instanceof String ) {
return super.remove(this.caseInsensitiveKeys.remove(convertKey((String) key)));
}
else {
return null;
}
}
@Override
public void clear() {
this.caseInsensitiveKeys.clear();
super.clear();
}
/**
* Convert the given key to a case-insensitive key.
* The default implementation converts the key
* to lower-case according to this Map's Locale.
* @param key the user-specified key
* @return the key to use for storing
* @see java.lang.String#toLowerCase(java.util.Locale)
*/
protected String convertKey(String key) {
return key.toLowerCase(this.locale);
}
}