/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.mj.impl.file;

import java.util.Vector;

import java.util.Enumeration;

import javax.microedition.io.file.FileSystemListener;

import com.nokia.mj.impl.fileutils.DriveInfo;

import com.nokia.mj.impl.fileutils.DriveListener;

import com.nokia.mj.impl.fileutils.DriveUtilities;

import com.nokia.mj.impl.rt.support.ApplicationInfo;

import com.nokia.mj.impl.rt.support.ApplicationUtils;

import com.nokia.mj.impl.rt.support.Jvm;

public final class FileSystemRegistryImpl implements DriveListener

{

    private static Vector iListeners = new Vector();

    private static Object iListenerLock = new Object();

    private static FileSystemRegistryImpl iDriveListener;

    static

    {

        try

        {

            Jvm.loadSystemLibrary("javafile");

        }

        catch (Exception e)

        {

            FileLogger.ELog("Unable to load javafile native library");

        }

    }

    private FileSystemRegistryImpl()

    {

    }

    /**

     * Please refer JSR 75 for more details.

     */

    public static Enumeration listRoots()

    {

        FileLogger.Log("--> FileSystemRegistry.listRoots()");

        // Access Check

        ApplicationUtils appUtils = ApplicationUtils.getInstance();

        FileInternalPermission perm = new FileInternalPermission("",

                FileAccessHelper.INTENT_READ);

        appUtils.checkPermission(perm);

        String domain = FileSystemUtils.getProtectionDomain();

        // Fetch the roots.

        Vector rootVector = FileSystemUtils.listRoots();

        Vector retValue = new Vector();

        for (int index = 0; index < rootVector.size(); index++)

        {

                retValue.addElement(rootVector.elementAt(index));

        }

        FileLogger.Log("<-- FileSystemRegistry.listRoots()");

        return retValue.elements();

    }

    /**

     * Please refer JSR 75 for more details.

     */

    public static boolean addFileSystemListener(FileSystemListener aListener)

    {

        FileLogger.Log("--> FileSystemregistryImpl.addFileSystemListener()");

        if (aListener == null)

        {

            throw new NullPointerException("Argument passed was null");

        }

        // Access Check

        ApplicationUtils appUtils = ApplicationUtils.getInstance();

        FileInternalPermission perm = new FileInternalPermission("",

                FileAccessHelper.INTENT_READ);

        appUtils.checkPermission(perm);

        boolean regSuccess = true;

        synchronized (iListenerLock)

        {

            iListeners.addElement(aListener);

            // If it is the first time, register with DriveUtilities.

            if (1 == iListeners.size())

            {

                iDriveListener = new FileSystemRegistryImpl();

                regSuccess = DriveUtilities.registerListener(iDriveListener);

            }

        }

        FileLogger.Log("<-- FileSystemregistryImpl.addFileSystemListener() "

                       + " returns: " + regSuccess);

        return regSuccess;

    }

    /**

     * Please refer JSR 75 for more details.

     */

    public static boolean removeFileSystemListener(FileSystemListener aListener)

    {

        FileLogger.Log("--> FileSystemregistryImpl.removeFileSystemListener()");

        if (aListener == null)

        {

            throw new NullPointerException("Argument passed was null");

        }

        boolean unregStatus = true;

        synchronized (iListenerLock)

        {

            iListeners.removeElement(aListener);

            if (0 == iListeners.size())

            {

                unregStatus = DriveUtilities.unregisterListener(iDriveListener);

                iDriveListener = null;

            }

        }

        FileLogger.Log("<-- FileSystemregistryImpl.removeFileSystemListener()"

                       + " returns: " + unregStatus);

        return unregStatus;

    }

    /**

     * Notifies all the Listeners on root change event.

     *

     * @param aStatus

     *            status of the root that has changed

     * @param aRoot

     *            root which has either been added or removed

     */

    static void notifyListeners(final int aStatus, final String aRoot)

    {

        FileLogger.Log("--> FileSystemregistryImpl.notifyListeners()");

        FileSystemListener tmpObj = null;

        for (int index = 0; index < iListeners.size(); ++index)

        {

            tmpObj = (FileSystemListener) iListeners.elementAt(index);

            tmpObj.rootChanged(aStatus, aRoot);

        }

        FileLogger.Log("<-- FileSystemregistryImpl.notifyListeners()");

    }

    /**

     * Callback from DriveUtilities once there is change in drive status.

     */

    public void driveChanged(final int aOperation, final DriveInfo aDriveInfo)

    {

        FileLogger.Log("--> FileSystemregistryImpl.driveChanged()");

        if (aOperation == DriveListener.REMOVABLE_MEDIA_INSERTED)

        {

            FileSystemRegistryImpl.notifyListeners(

                FileSystemListener.ROOT_ADDED, aDriveInfo.iRootPath

                .replace('\\', '/'));

        }

        if (aOperation == DriveListener.REMOVABLE_MEDIA_REMOVED)

        {

            FileSystemRegistryImpl.notifyListeners(

                FileSystemListener.ROOT_REMOVED, aDriveInfo.iRootPath

                .replace('\\', '/'));

        }

        FileLogger.Log("<-- FileSystemregistryImpl.driveChanged()");

    }

}