/* * Copyright 2002-2014 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. * * <p>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. * * <p>Does <i>not</i> support {@code null} keys. * * @author Juergen Hoeller * @since 1.0 */ @SuppressWarnings("serial") public class LinkedCaseInsensitiveMap<V> extends LinkedHashMap<String, V> { private final Map<String, String> 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<String, String>(); 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<String, String>(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<? extends String, ? extends V> map) { if (map.isEmpty()) { return; } for (Map.Entry<? extends String, ? extends V> 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. * <p>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); } }