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.AbstractSet;
import java.util.Iterator;
import java.util.Map;

/**
 * This is the key set for an abstract map.
 *
 * @param <K> The key type.
 * @param <V> The value stored.
 * @since 2018/10/10
 */
public final class MapKeySetView<K, V>
    extends AbstractSet<K>
{
    /** The backing map. */
    protected final Map<K, V> map;
    
    /** Is adding allowed? */
    protected final boolean allowAdd;
    
    /**
     * Initializes the set.
     *
     * @param __map The backing map
     * @param __allowAdd Is adding allowed in the map?
     * @throws NullPointerException On null arguments.
     * @since 2018/11/01
     */
    public MapKeySetView(Map<K, V> __map, boolean __allowAdd)
        throws NullPointerException
    {
        if (__map == null)
            throw new NullPointerException("NARG");
        
        this.map = __map;
        this.allowAdd = __allowAdd;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/11/28
     */
    @Override
    public boolean add(K __k)
    {
        if (!this.allowAdd)
            throw new UnsupportedOperationException("RORO");
        
        // Store a null value here
        Map<K, V> map = this.map;
        boolean contained = map.containsKey(__k);
        map.put(__k, null);
        
        // Only if it is actually contained here
        return !contained;
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/11/01
     */
    @SuppressWarnings("SuspiciousMethodCalls")
    @Override
    public final boolean contains(Object __o)
    {
        return this.map.containsKey(__o);
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/10/10
     */
    @Override
    public final Iterator<K> iterator()
    {
        return new MapKeySetIterator<K, V>(this.map.entrySet().iterator());
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/11/28
     */
    @SuppressWarnings("SuspiciousMethodCalls")
    @Override
    public boolean remove(Object __o)
    {
        // Remove the item from the map, but check to ensure it has it before
        // that is actually done
        Map<K, V> map = this.map;
        boolean hasKey = map.containsKey(__o);
        map.remove(__o);
        
        return hasKey;
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/10/10
     */
    @Override
    public final int size()
    {
        return this.map.size();
    }
}