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 net.multiphasicapps.io;

/**
 * This is a future that is a forward of another future.
 *
 * @since 2020/11/29
 */
public final class ChunkForwardedFuture
    implements ChunkFuture
{
    /** Initialized to zero? */
    protected final boolean zeroInit;
    
    /** The future to get the value from. */
    private volatile ChunkFuture _future;
    
    /** An offset, which may be a future. */
    private volatile ChunkFuture _offset;
    
    /**
     * Initializes the future with nothing set.
     * 
     * @since 2021/01/20
     */
    public ChunkForwardedFuture()
    {
        this(false);
    }
    
    /**
     * Initialize the future to a value of zero?
     * 
     * @param __zeroInit Is this initialized to zero?
     * @since 2021/09/06
     */
    public ChunkForwardedFuture(boolean __zeroInit)
    {
        this.zeroInit = __zeroInit;
    }
    
    /**
     * Initializes the future with values optionally set.
     * 
     * @param __future The future value.
     * @param __offset The potential offset.
     * @since 2021/01/20
     */
    public ChunkForwardedFuture(ChunkFuture __future, ChunkFuture __offset)
    {
        this._future = __future;
        this._offset = __offset;
        this.zeroInit = false;
    }
    
    /**
     * {@inheritDoc}
     * @since 2020/11/29
     */
    @Override
    public int get()
    {
        synchronized (this)
        {
            // Ensure the future is actually set
            ChunkFuture future = this._future;
            if (future == null)
            {
                // If zero initializing, ignore any offset and just return
                // zero
                if (this.zeroInit)
                    return 0;
                    
                /* {@squirreljme.error BD05 A future was never set.} */
                throw new IllegalStateException("BD05");
            }
            
            // Future with optional offset applied?
            ChunkFuture offset = this._offset;
            return future.get() + (offset == null ? 0 : offset.get());
        }
    }
    
    /**
     * Checks if this future is set or not.
     * 
     * @return If this is set or not.
     * @since 2020/12/06
     */
    public boolean isSet()
    {
        synchronized (this)
        {
            return null != this._future;
        }
    }
    
    /**
     * Sets the future to read a value from.
     * 
     * @param __future The future to set.
     * @throws NullPointerException On null arguments.
     * @since 2020/11/29
     */
    public void set(ChunkFuture __future)
        throws NullPointerException
    {
        this.set(__future, null);
    }
    
    /**
     * Sets the future to read a value from.
     * 
     * @param __future The future to set.
     * @param __off Offset for the future.
     * @throws NullPointerException On null arguments.
     * @since 2021/01/17
     */
    public void set(ChunkFuture __future, int __off)
        throws NullPointerException
    {
        this.set(__future, new ChunkFutureInteger(__off));
    }
    
    /**
     * Sets the future to read a value from.
     * 
     * @param __future The future to set.
     * @param __off Optional offset for the future.
     * @throws NullPointerException On null arguments.
     * @since 2021/01/17
     */
    public void set(ChunkFuture __future, ChunkFuture __off)
        throws NullPointerException
    {
        if (__future == null)
            throw new NullPointerException("NARG");
        
        synchronized (this)
        {
            this._future = __future;
            this._offset = __off;
        }
    }
    
    /**
     * Sets the future to this integer value.
     * 
     * @param __value The value to set.
     * @return The generated future.
     * @since 2020/12/06
     */
    public ChunkFutureInteger setInt(int __value)
    {
        ChunkFutureInteger future = new ChunkFutureInteger(__value);
        
        this.set(future, null);
        
        return future;
    }
}