/*
 * Copyright 2002-2009 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 net.hasor.utils.ref;
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</code> keys.
 *
 * @author Juergen Hoeller
 * @since 3.0
 */
public class LinkedCaseInsensitiveMap<V> extends LinkedHashMap<String, V> {
    private static final long                serialVersionUID = -2744548964742290311L;
    private final        Map<String, String> caseInsensitiveKeys;
    private final        Locale              locale;

    /**
     * Create a new LinkedCaseInsensitiveMap for the default Locale.
     * @see 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 String#toLowerCase(Locale)
     */
    public LinkedCaseInsensitiveMap(final 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 String#toLowerCase()
     */
    public LinkedCaseInsensitiveMap(final 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 String#toLowerCase(Locale)
     */
    public LinkedCaseInsensitiveMap(final int initialCapacity, final Locale locale) {
        super(initialCapacity);
        this.caseInsensitiveKeys = new HashMap<>(initialCapacity);
        this.locale = locale != null ? locale : Locale.getDefault();
    }

    @Override
    public V put(final String key, final V value) {
        this.caseInsensitiveKeys.put(this.convertKey(key), key);
        return super.put(key, value);
    }

    @Override
    public boolean containsKey(final Object key) {
        return key instanceof String && this.caseInsensitiveKeys.containsKey(this.convertKey((String) key));
    }

    @Override
    public V get(final Object key) {
        if (key instanceof String) {
            return super.get(this.caseInsensitiveKeys.get(this.convertKey((String) key)));
        } else {
            return null;
        }
    }

    @Override
    public V remove(final Object key) {
        if (key instanceof String) {
            return super.remove(this.caseInsensitiveKeys.remove(this.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 String#toLowerCase(Locale)
     */
    protected String convertKey(final String key) {
        return key.toLowerCase(this.locale);
    }
}
