/*
 * Copyright  1990-2009 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation. 
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

package com.sun.j2me.app;

import com.sun.j2me.security.Permission;
import com.sun.j2me.security.AccessController;
import com.sun.midp.midlet.MIDletStateHandler;
import com.sun.midp.midletsuite.MIDletSuiteImpl;
import com.sun.midp.midlet.MIDletSuite;
import java.io.InputStream;

/**
 * Abstraction for application package
 */
public class AppPackage {
    
    /** Static instance. Only one package can be run in a isolate */
    private static AppPackage instance = new AppPackage();
    
    /** Guard from 'new' operator */
    private AppPackage() {
    }
    
    public static AppPackage getInstance() {
        return instance;
    }
    
    public int getId() {
        return MIDletStateHandler.getMidletStateHandler().
            getMIDletSuite().getID();
    }


    /** Unused ID */
    public static final int UNUSED_APP_ID = -1;
   
    /**
     * Returns permission status for the specified permission
     *
     * @param p permission to check
     * @return 1 if allowed; 0 if denied; -1 if status is unknown
     */
    public int checkPermission(Permission p) {
        /*
         * IMPL_NOTE: The corresponding method in MIDletSuite used to check
         * for permissions silently, i.e. without throwing SecurityException
         * or asking user if he allows to proceed.
         * This functionality should be added to AccessController; until then,
         * it is acceptable to return "unknown", so that security-sensitive
         * code will call checkForPermission() anyway.
         */
        return -1;
    }    
    
    /**
     * Checks for specified permission status. Throws an exception
     * if permission is not allowed. May be blocked to ask user
     *
     * @param p a permission to check
     * @exception SecurityException if permission is not allowed
     * @exception InterruptedException if another thread interrupts a calling
     *  thread while asking user
     */
    public void checkForPermission(Permission p) throws InterruptedException {
        AccessController.checkPermission(p.getName(), p.getResource(), p.getExtraValue());
    }    
    
    /**
     * Throws an exception if a status for the permission is not allowed
     *
     * @param p a permission to check
     * @exception SecurityException if a status for the permission is not allowed
     */
    public void checkIfPermissionAllowed(Permission p) {
        if (checkPermission(p) != 1) {
            throw new SecurityException();
        }
    }    

    /**
     * Gets the name of CA that authorized this suite.
     *
     * @return name of a CA or null if the suite was not signed
     */
    public String getCA() {
        MIDletSuite ms =
            MIDletStateHandler.getMidletStateHandler().getMIDletSuite();

        if (ms instanceof com.sun.midp.midletsuite.MIDletSuiteImpl) {
            return ((MIDletSuiteImpl)ms).getInstallInfo().getCA();
        } 
        else {
            return null;
        }
    }

    /**
     * Finds a resource with a given name.  This method returns null if no
     * resource with this name is found.  
     *
     * @param name  name of the desired resource
     * @return      a <code>java.io.InputStream</code> object.
     * @throws NullPointerException if <code>name</code> is <code>null</code>.
     */     
    public InputStream getResourceAsStream(String name) {
        return getClass().getResourceAsStream(name);
    }
    
}