gistfile1.txt

/*******************************************************************************
 * Copyright 2015 ANON GISTER.
 * 
 * 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.
 ******************************************************************************/
 
import java.util.LinkedHashMap;
import java.util.Map;
 
public class IterableLinkedMap<K, V> extends LinkedHashMap<K, V> {
 
    LinkedHashMap<Integer, K> keyMap = new LinkedHashMap<Integer, K>();
 
    @Override
    public V put(K key, V value) {
        V put = super.put(key, value);
        if (null == put){
            keyMap.put(keyMap.size(), key);
        }
        return put;
    }
 
    public V getPosition(int position) {
        K key = keyMap.get(position);
        if (key != null){
            return get(key);
        }
        return null;
    }
 
    @Override
    public void clear() {
        super.clear();
        keyMap.clear();
    }
 
    @Override
    protected boolean removeEldestEntry(Map.Entry<K, V> eldest) {
        return false;
    }
 
    @Override
    public V remove(Object key) {
        V remove = super.remove(key);
        if (remove != null){
            int i = 0;
            LinkedHashMap<Integer, K> newKeyMap = new LinkedHashMap<Integer, K>();
            for (K k : keyMap.values()) {
                if (!k.equals(key)) {
                    newKeyMap.put(i, k);
                    i++;
                }
            }
            assert(newKeyMap.size() == size());
            keyMap = newKeyMap;
        }
        return remove;
    }
 
    @Override
    public void putAll(Map<? extends K, ? extends V> map) {
        for (Map.Entry<? extends K, ? extends V> entry: map.entrySet()){
            put(entry.getKey(), entry.getValue());
        }
    }
}