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 cc.squirreljme.vm;

import cc.squirreljme.runtime.cldc.archive.ArchiveStreamEntry;
import cc.squirreljme.runtime.cldc.archive.ArchiveStreamReader;
import java.io.Closeable;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;

/**
 * Stream reader for any class library, could be used with the AOT framework.
 *
 * @since 2022/08/20
 */
public final class VMClassLibraryStreamReader
    implements ArchiveStreamReader
{
    /** The source library to read from. */
    private final VMClassLibrary _library;
    
    /** Iterator over library entries. */
    private Iterator<String> _iterator;
    
    /**
     * Initializes the library reader.
     * 
     * @param __library The library to wrap.
     * @throws NullPointerException On null arguments.
     * @since 2022/08/20
     */
    public VMClassLibraryStreamReader(VMClassLibrary __library)
        throws NullPointerException
    {
        if (__library == null)
            throw new NullPointerException("NARG");
        
        this._library = __library;
        this._iterator = Arrays.asList(__library.listResources()).iterator();
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/08/20
     */
    @Override
    public void close()
        throws IOException
    {
        VMClassLibrary library = this._library;
        if (library instanceof Closeable)
            ((Closeable)library).close();
    }
    
    /**
     * {@inheritDoc}
     * @since 2022/08/20
     */
    @Override
    public ArchiveStreamEntry nextEntry()
        throws IOException
    {
        // Nothing left to process?
        Iterator<String> iterator = this._iterator;
        if (!iterator.hasNext())
            return null;
        
        // Setup next entry
        String name = iterator.next();
        return new VMClassLibraryStreamEntry(name,
            this._library.resourceAsStream(name));
    }
}