SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// Multi-Phasic Applications: 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 java.util;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.lang.ref.WeakReference;

/**
 * Wrapper for keys and values within the map.
 *
 * @param <K> The key being wrapped.
 * @since 2023/02/09
 */
final class __WeakHashMapKey__<K>
{
    /** The reference used. */
    volatile WeakReference<K> _ref;
    
    /** The hash code, for bucket mapping. */
    final int _hashCode;
    
    /**
     * Initializes the key wrapper.
     *
     * @param __key The key used.
     * @since 2023/02/09
     */
    __WeakHashMapKey__(K __key)
    {
        // Null keys are valid!
        if (__key == null)
        {
            this._ref = null;
            this._hashCode = 0;
        }
        
        // Has a value, so use that
        else
        {
            this._ref = new WeakReference<>(__key);
            this._hashCode = __key.hashCode();
        }
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2023/02/09
     */
    @Override
    public boolean equals(Object __o)
    {
        if (__o == this)
            return true;
        if (!(__o instanceof __WeakHashMapKey__))
            return false;
        
        // Check if it is the same, compare the ref itself because although
        // for every reference used it will be null, otherwise both sides
        // must not be null, so we can cleanly deref without a NPE
        __WeakHashMapKey__<?> o = (__WeakHashMapKey__<?>)__o;
        return this._hashCode == o._hashCode && (this._ref == o._ref ||
            (this._ref != null && o._ref != null && Objects.equals(
            this._ref.get(), o._ref.get())));
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2023/02/09
     */
    @Override
    public int hashCode()
    {
        return this._hashCode;
    }
    
    /**
     * {@inheritDoc}
     *
     * @since 2023/02/09
     */
    @Override
    public String toString()
    {
        // Defaults to null essentially
        WeakReference<K> ref = this._ref;
        if (ref == null)
            return "null";
        
        // This should not occur!
        K k = ref.get();
        if (k == null)
            throw Debugging.oops("WHMRef");
        
        // Use the representation of this object instead
        return k.toString();
    }
}