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 a synchronized iterator over entry set iterators.
 *
 * @param <K> The key.
 * @param <V> The value.
 * @since 2019/05/05
 */
public class SynchronizedEntrySetIterator<K, V>
    implements Iterator<Map.Entry<K, V>>
{
    /** The locking object. */
    protected final Object lock;
    
    /** The backing iterator. */
    protected final Iterator<Map.Entry<K, V>> iterator;
    
    /**
     * Initializes the synchronized iterator.
     *
     * @param __lock The locking object.
     * @param __it The iterator object.
     * @throws NullPointerException On null arguments.
     * @since 2019/05/05
     */
    public SynchronizedEntrySetIterator(Object __lock,
        Iterator<Map.Entry<K, V>> __it)
        throws NullPointerException
    {
        if (__lock == null || __it == null)
            throw new NullPointerException("NARG");
        
        this.lock = __lock;
        this.iterator = __it;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/05/05
     */
    @Override
    public final boolean hasNext()
    {
        synchronized (this.lock)
        {
            return this.iterator.hasNext();
        }
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/05/05
     */
    @Override
    public final Map.Entry<K, V> next()
        throws NoSuchElementException
    {
        Object lock = this.lock;
        synchronized (lock)
        {
            return new SynchronizedMapEntry<K, V>(lock, this.iterator.next());
        }
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/05/05
     */
    @Override
    public final void remove()
        throws IllegalStateException, UnsupportedOperationException
    {
        synchronized (this.lock)
        {
            this.iterator.remove();
        }
    }
}