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

/**
 * This iterates over the sorted set.
 *
 * @since 2016/09/06
 */
class __SortedTreeIterator__<K, V>
    implements Iterator<Map.Entry<K, V>>
{
    /** The owning map. */
    protected final SortedTreeMap<K, V> map;
    
    /** The current node position. */
    private volatile __SortedTreeData__<K, V> _at;
    
    /** The last visited node (for deletion). */
    private volatile __SortedTreeData__<K, V> _last;
    
    /**
     * Iterates over the given map.
     *
     * @param __m The map to iterate over.
     * @since 2016/09/06
     */
    __SortedTreeIterator__(SortedTreeMap<K, V> __m)
        throws NullPointerException
    {
        // Check
        if (__m == null)
            throw new NullPointerException("NARG");
        
        // Set
        this.map = __m;
        this._at = __m._min;
    }
    
    /**
     * {@inheritDoc}
     * @since 2016/09/06
     */
    @Override
    public boolean hasNext()
    {
        __SortedTreeData__<K, V> at = this._at;
        if (at == null)
            return false;
        return (this.__detect(at) != null);
    }
    
    /**
     * {@inheritDoc}
     * @since 2016/09/06
     */
    @Override
    public Map.Entry<K, V> next()
    {
        /* {@squirreljme.error AC06 No more elements to iterate over.} */
        __SortedTreeData__<K, V> rv = this._at;
        if (rv == null)
            throw new NoSuchElementException("AC06");
        
        // Make sure the value was not removed
        rv = this.__detect(rv);
        
        // Store last node (for removal) and iterate to the next node value
        this._last = rv;
        this._at = rv._next;
        
        return rv;
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/03/25
     */
    @Override
    public void remove()
    {
        /* {@squirreljme.error AC07 No last entry exists for deletion.} */
        __SortedTreeData__<K, V> last = this._last;
        if (last == null)
            throw new IllegalStateException("AC07");
        
        // Remove the entry
        this._last = null;
        this.map.remove(last._key);
    }
    
    /**
     * Detects if concurrent modification has occured.
     *
     * @param __data The data to check.
     * @return {@code __data}.
     * @throws ConcurrentModificationException If modification was detected.
     * @throws NullPointerException On null arguments. 
     * @since 2017/03/30
     */
    private __SortedTreeData__<K, V> __detect(
        __SortedTreeData__<K, V> __data)
        throws ConcurrentModificationException, NullPointerException
    {
        // Check
        if (__data == null)
            throw new NullPointerException("NARG");
        
        /* {@squirreljme.error AC08 Referenced node was deleted.} */
        if (__data._node == null)
            throw new ConcurrentModificationException("AC08");
        
        return __data;
    }
}