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 net.multiphasicapps.collections;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;

/**
 * This is the base class for the identity set.
 *
 * @param <T> The type of element to store in the set.
 * @since 2017/12/28
 */
abstract class __IdentityBaseSet__<T>
    extends AbstractSet<T>
{
    /** The set to use as a backing storage. */
    private final Set<Identity<T>> _backing;
    
    /**
     * Initializes the base set using the given backing set.
     *
     * @param __back The set to back with.
     * @throws NullPointerException On null arguments.
     * @since 2017/12/28
     */
    __IdentityBaseSet__(Set<Identity<T>> __back)
        throws NullPointerException
    {
        if (__back == null)
            throw new NullPointerException("NARG");
        
        this._backing = __back;
    }
    
    /**
     * Initializes the base set using the given backing set.
     *
     * @param __back The set to back with.
     * @param __from The collection to source data from.
     * @throws NullPointerException On null arguments.
     * @since 2017/12/28
     */
    __IdentityBaseSet__(Set<Identity<T>> __back,
        Collection<? extends T> __from)
        throws NullPointerException
    {
        if (__back == null || __from == null)
            throw new NullPointerException("NARG");
        
        this._backing = __back;
        this.addAll(__from);
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final boolean add(T __t)
    {
        if (__t == null)
            return this._backing.add(null);
        return this._backing.add(new Identity<T>(__t));
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final void clear()
    {
        this._backing.clear();
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @SuppressWarnings("unchecked")
    @Override
    public final boolean contains(Object __o)
    {
        return this._backing.contains(new Identity<T>((T)__o));
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final boolean equals(Object __o)
    {
        if (this == __o)
            return true;
        
        if (!(__o instanceof Set))
            return false;
        
        Set<?> o = (Set<?>)__o;
        return this.size() == o.size() &&
            this.containsAll(o);
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final boolean isEmpty()
    {
        return this._backing.isEmpty();
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final Iterator<T> iterator()
    {
        return new __Iterator__();
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @SuppressWarnings("unchecked")
    @Override
    public final boolean remove(Object __o)
    {
        return this._backing.remove(new Identity<T>((T)__o));
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public final int size()
    {
        return this._backing.size();
    }
    
    /**
     * Iterates over wrapped entries.
     *
     * @since 2017/12/28
     */
    final class __Iterator__
        implements Iterator<T>
    {
        /** The boxed iterator. */
        protected final Iterator<Identity<T>> boxed =
            __IdentityBaseSet__.this._backing.iterator();
        
        /**
         * {@inheritDoc}
         * @since 2017/12/28
         */
        @Override
        public boolean hasNext()
        {
            return this.boxed.hasNext();
        }
        
        /**
         * {@inheritDoc}
         * @since 2017/12/28
         */
        @Override
        public T next()
        {
            Identity<T> rv = this.boxed.next();
            if (rv == null)
                return null;
            return rv.get();
        }
        
        /**
         * {@inheritDoc}
         * @since 2017/12/28
         */
        @Override
        public void remove()
        {
            this.boxed.remove();
        }
    }
}