SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.runtime.cldc.util;

import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;

/**
 * This is the iterator over the map's key set.
 *
 * @param <K> The key type.
 * @param <V> The value type.
 * @since 2018/11/01
 */
public final class MapKeySetIterator<K, V>
    implements Iterator<K>
{
    /** The entry set iterator. */
    protected final Iterator<Map.Entry<K, V>> iterator;
    
    /**
     * Initializes the iterator.
     *
     * @param __it The backing iterator.
     * @throws NullPointerException On null arguments.
     * @since 2018/11/01
     */
    public MapKeySetIterator(Iterator<Map.Entry<K, V>> __it)
        throws NullPointerException
    {
        if (__it == null)
            throw new NullPointerException("NARG");
        
        this.iterator = __it;
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2018/11/01
     */
    @Override
    public boolean hasNext()
    {
        return this.iterator.hasNext();
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2018/11/01
     */
    @Override
    public K next()
        throws NoSuchElementException
    {
        return this.iterator.next().getKey();
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2018/11/01
     */
    @Override
    public void remove()
    {
        this.iterator.remove();
    }
}