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.classfile;

import cc.squirreljme.runtime.cldc.util.SortedTreeMap;
import cc.squirreljme.runtime.cldc.util.UnmodifiableIterator;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.Iterator;
import java.util.Map;
import net.multiphasicapps.collections.UnmodifiableMap;

/**
 * This is the stack map table which is used for verification purposes.
 *
 * @since 2017/10/09
 */
public final class StackMapTable
    implements Iterable<Map.Entry<Integer, StackMapTableState>>
{
    /** Stack map states. */
    private final Map<Integer, StackMapTableState> _states;
    
    /** String form. */
    private Reference<String> _string;
    
    /**
     * Initializes the stack map table.
     *
     * @param __s The input states.
     * @throws NullPointerException On null arguments.
     * @since 2017/10/16
     */
    StackMapTable(Map<Integer, StackMapTableState> __s)
        throws NullPointerException
    {
        if (__s == null)
            throw new NullPointerException("NARG");
        
        this._states = new SortedTreeMap<>(__s);
    }
    
    /**
     * Returns the stack map table state for the given entry.
     *
     * @param __a The address to get.
     * @return The state for the given address or {@code null} if it there is
     * no entry.
     * @since 2017/10/16
     */
    public StackMapTableState get(int __a)
    {
        return this._states.get(__a);
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/04/16
     */
    @Override
    public final Iterator<Map.Entry<Integer, StackMapTableState>> iterator()
    {
        return UnmodifiableIterator.<Map.Entry<Integer, StackMapTableState>>of(
            UnmodifiableMap.<Integer, StackMapTableState>of(
                this._states).entrySet().iterator());
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/01/21
     */
    @Override
    public final String toString()
    {
        Reference<String> ref = this._string;
        String rv;
        
        if (ref == null || null == (rv = ref.get()))
            this._string = new WeakReference<>((rv = this._states.toString()));
        
        return rv;
    }
}