Copyright (c) 2010, 2016 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2010, 2016 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.osgi.framework.util;

import java.util.*;

Simple map when dealing with small amounts of entries.
This class also provides a Collections view of the keys
Type parameters:
<K> – The key type
<V> – the value type/**
 * Simple map when dealing with small amounts of entries.
 * This class also provides a Collections view of the keys
 *
 * @param <K> The key type
 * @param <V> the value type
 */
public class ArrayMap<K, V> implements Collection<K> {
	final List<K> keys;
	final List<V> values;

	public ArrayMap(int initialCapacity) {
		keys = new ArrayList<>(initialCapacity);
		values = new ArrayList<>(initialCapacity);
	}

	
Note that the keys and values are not copied.  Changes to this ArrayMap
will change the values of the keys and values Lists.
Params:
keys – 
values – /**
	 * Note that the keys and values are not copied.  Changes to this ArrayMap
	 * will change the values of the keys and values Lists.
	 * @param keys
	 * @param values
	 */
	public ArrayMap(List<K> keys, List<V> values) {
		if (keys.size() != values.size())
			throw new IllegalArgumentException("Keys and values size must be equal."); //$NON-NLS-1$
		this.keys = keys;
		this.values = values;
	}

	public V get(K key) {
		int index = keys.indexOf(key);
		if (index < 0)
			return null;
		return values.get(index);
	}

	public void put(K key, V value) {
		int index = keys.indexOf(key);
		if (index > 0) {
			values.set(index, value);
		} else {
			keys.add(key);
			values.add(value);
		}
	}

	@Override
	public boolean remove(Object key) {
		int index = keys.indexOf(key);
		if (index < 0)
			return false;
		keys.remove(index);
		values.remove(index);
		return true;
	}

	@Override
	public void clear() {
		keys.clear();
		values.clear();
	}

	public List<K> getKeys() {
		return new ArrayList<>(keys);
	}

	public List<V> getValues() {
		return new ArrayList<>(values);
	}

	@Override
	public int size() {
		return keys.size();
	}

	@Override
	public boolean isEmpty() {
		return keys.isEmpty();
	}

	@Override
	public boolean contains(Object o) {
		return keys.contains(o);
	}

	@Override
	public Iterator<K> iterator() {
		final Iterator<K> keyIter = keys.iterator();
		final Iterator<V> valueIter = values.iterator();

		return new Iterator<K>() {
		@Override
			public boolean hasNext() {
				return keyIter.hasNext();
			}

		@Override
			public K next() {
				valueIter.next();
				return keyIter.next();
			}

		@Override
			public void remove() {
				valueIter.remove();
				keyIter.remove();
			}
		};
	}

	@Override
	public Object[] toArray() {
		return keys.toArray();
	}

	@Override
	public <T> T[] toArray(T[] a) {
		return keys.toArray(a);
	}

	@Override
	public boolean add(K o) {
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean containsAll(Collection<?> c) {
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean addAll(Collection<? extends K> c) {
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean removeAll(Collection<?> c) {
		boolean result = false;
		for (Object key : c)
			result |= remove(key);
		return result;
	}

	@Override
	public boolean retainAll(Collection<?> c) {
		boolean result = false;
		Object[] keyArray = keys.toArray();
		for (Object key : keyArray) {
			if (!c.contains(key))
				result |= remove(key);
		}
		return result;
	}

	public K getKey(int index) {
		return keys.get(index);
	}

	public V getValue(int index) {
		return values.get(index);
	}

	public void sort(Comparator<K> comparator) {
		List<K> sortedKeys = new ArrayList<>(keys);
		Collections.sort(sortedKeys, comparator);
		List<V> sortedValues = new ArrayList<>(sortedKeys.size());
		for (K key : sortedKeys) {
			sortedValues.add(getByIdentity(key));
		}
		clear();
		for (int i = 0; i < sortedKeys.size(); i++) {
			put(sortedKeys.get(i), sortedValues.get(i));
		}
	}

	private V getByIdentity(K key) {
		int index = 0;
		for (K existing : keys) {
			if (existing == key)
				return getValue(index);
			index++;
		}
		return null;
	}
}