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.jvm.mle.constants;

/**
 * This class contains all of the packages which are protected and are not
 * permitted to have additional classes added within.
 *
 * @since 2020/06/21
 */
public final class ProtectedPackages
{
    /**
     * Not used.
     * 
     * @since 2020/06/21
     */
    private ProtectedPackages()
    {
    }
    
    /**
     * Checks to see if the package is protected, if it is then no other
     * JAR may add to it. This will be recursively checked so any package
     * under a given one will not be permitted.
     * 
     * @param __name The package name, must be in binary name form.
     * @return If this package is protected.
     * @throws IllegalArgumentException If the name contains a period as this
     * means it potentially is being called incorrectly.
     * @throws NullPointerException On null arguments.
     * @since 2020/06/21
     */
    public static boolean isProtectedPackage(String __name)
        throws IllegalArgumentException, NullPointerException
    {
        if (__name == null)
            throw new NullPointerException("NARG");
        
        /* {@squirreljme.error ZZ37 Package contains a period. (The name)} */
        if (__name.indexOf('.') >= 0)
            throw new IllegalArgumentException("ZZ37 " + __name);
        
        // Try these
        switch (__name)
        {
                // These packages must never be changed
            case "cc/squirreljme/jvm":
            case "java/lang":
                return true;
        }
        
        // No more packages to check
        int lastSlash = __name.lastIndexOf('/');
        if (lastSlash < 0)
            return false;
        
        // Recurse into parent packages
        return ProtectedPackages.isProtectedPackage(
            __name.substring(0, lastSlash));
    }
}