OS.java Source code

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Here is the source code for OS.java

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/*
 *  OS.java
 *  2007-04-14
 */

//cb.aloe.util;
import java.io.File;
import java.util.ArrayList;

/**
 * Class representing a standard operating system platform, WIN, MAC, or POSIX.
 * 
 * @author Christopher Bach
 */
public final class OS {
    public static final OS WIN = new OS("WIN");

    public static final OS MAC = new OS("MAC");

    public static final OS POSIX = new OS("POSIX");

    private String ourOS = "";

    /**
     * Private constructor to avert instantiation.
     */
    private OS(String os) {
        ourOS = os;
    }

    /**
     * Returns a String representing this OS object.
     */
    public String toString() {
        return ourOS;
    }

    /**
     * Returns the first readable and writable application data folder appropriate
     * to this OS.
     */
    public static File getAppDataFolder() {
        File[] folders = listAppDataFolders();

        for (int i = 0; i < folders.length; i++) {
            File folder = folders[i];
            if (folder.canRead() && folder.canWrite())
                return folder;
        }

        return null;
    }

    /**
     * Returns the first readable and writable user data folder appropriate to
     * this OS.
     */
    public static File getUserDataFolder() {
        File[] folders = listUserDataFolders();

        for (int i = 0; i < folders.length; i++) {
            File folder = folders[i];
            if (folder.canRead() && folder.canWrite())
                return folder;
        }

        return null;
    }

    /**
     * Returns a list of the preferred locations for storing application- specific
     * data in descending order.
     */
    public static File[] listAppDataFolders() {
        String home = System.getProperty("user.home");
        ArrayList folders = new ArrayList();

        if (isWinNT()) // NT/2000/XP
        {
            // C:\Documents and Settings\All Users\Application Data
            // Surmise that the "All Users" folder will be a child of the
            // parent of the current user's home folder:
            File folder = new File(home).getParentFile();
            folders.add(new File(folder, "All Users\\Application Data"));
        }

        else if (isWin9X()) // 95/98/ME
        {
            // C:\Windows
            folders.add(new File(home));
        }

        else if (isVista()) {
            // C:\ProgramData
            File folder = new File(home).getParentFile().getParentFile();
            folders.add(new File(folder, "ProgramData"));

            // C:\Users\Public\AppData
            folder = new File(home).getParentFile();
            folders.add(new File(folder, "Public\\AppData"));
        }

        else if (isMac()) {
            folders.add(new File("/Library/Application Support"));
        }

        else {
            folders.add(new File("/var/local"));
            folders.add(new File("/var"));
        }

        // folders.addAll(Arrays.asList(listUserDataFolders()));
        File[] files = new File[folders.size()];
        return (File[]) folders.toArray(files);
    }

    /**
     * Returns a list of the preferred locations for storing user- specific data
     * in descending order.
     */
    public static File[] listUserDataFolders() {
        String home = System.getProperty("user.home");
        ArrayList folders = new ArrayList();

        if (isWinNT()) {
            folders.add(new File(home + "\\Application Data"));
            folders.add(new File(home + "\\Local Settings\\Application Data"));
        }

        else if (isVista()) {
            folders.add(new File(home + "\\AppData"));
            folders.add(new File(home + "\\AppData\\Local"));
        }

        else if (isMac()) {
            folders.add(new File(home + "/Library/Application Support"));
        }

        folders.add(new File(home));

        File[] files = new File[folders.size()];
        return (File[]) folders.toArray(files);
    }

    /**
     * Returns the name of the current operating system platform as listed in the
     * System properties.
     */
    public static final String getOSName() {
        return System.getProperty("os.name");
    }

    /**
     * Returns the OS representing the current operating system platform.
     */
    public static final OS getOS() {
        String os = System.getProperty("os.name").toLowerCase();

        if (os.indexOf("windows") >= 0)
            return WIN;
        else if (os.indexOf("mac os") >= 0)
            return MAC;
        else
            return POSIX;
    }

    /**
     * Returns whether or not the current operating system is a Microsoft Windows
     * platform.
     */
    public static final boolean isWindows() {
        return getOS() == WIN;
    }

    /**
     * Returns whether or not the current operating system is a Microsoft Windows
     * 9X platform (Windows 95/98/ME).
     */
    public static boolean isWin9X() {
        if (getOS() != WIN)
            return false;

        String os = getOSName();
        if (os.indexOf("95") >= 0 || os.indexOf("98") >= 0 || os.indexOf("me") >= 0)
            return true;
        return false;
    }

    /**
     * Returns whether or not the current operating system is a Microsoft Windows
     * NT platform (Windows NT/2000/2003/XP).
     */
    public static boolean isWinNT() {
        if (getOS() != WIN)
            return false;

        String os = getOSName();
        if (os.indexOf("NT") >= 0 || os.indexOf("2000") >= 0 || os.indexOf("2003") >= 0 || os.indexOf("XP") >= 0)
            return true;
        return false;
    }

    /**
     * Returns whether or not the current operating system is a Microsoft Windows
     * Vista platform.
     */
    public static boolean isVista() {
        if (getOS() != WIN)
            return false;

        String os = getOSName();
        return (os.indexOf("Vista") >= 0);
    }

    /**
     * Returns whether or not the current operating system is the Apple Macintosh
     * OS X platform.
     */
    public static final boolean isMac() {
        return getOS() == MAC;
    }

    /**
     * Returns whether or not the current operating system is a Posix-compatible
     * platform (Unix, Linux, Solaris, etc).
     */
    public static final boolean isPosix() {
        return getOS() == POSIX;
    }

}