class PDTransparencyGroupAttributes implements COSObjectable
{
    private final COSDictionary dictionary;
    private PDColorSpace colorSpace;

    /**
     * Creates a group object with /Transparency subtype entry.
     */
    public PDTransparencyGroupAttributes()
    {
        dictionary = new COSDictionary();
        dictionary.setItem(COSName.S, COSName.TRANSPARENCY);
    }

    /**
     * Creates a group object from a given dictionary
     * @param dic {@link COSDictionary} object
     */
    public PDTransparencyGroupAttributes(COSDictionary dic)
    {
        dictionary = dic;
    }

    @Override
    public COSDictionary getCOSObject()
    {
        return dictionary;
    }

    /**
     * Returns the group color space or null if it isn't defined.
     *
     * @return the group color space.
     * @throws IOException if the colorspace could not be created
     */
    public PDColorSpace getColorSpace() throws IOException
    {
        return getColorSpace(null);
    }

    /**
     * Returns the group color space or null if it isn't defined.
     *
     * @param resources useful for its cache. Can be null.
     * @return the group color space.
     * @throws IOException if the colorspace could not be created
     */
    public PDColorSpace getColorSpace(PDResources resources) throws IOException
    {<FILL_FUNCTION_BODY>}

    /**
     * Returns true if this group is isolated. Isolated groups begin with the fully transparent image, non-isolated
     * begin with the current backdrop.
     * 
     * @return true if this group is isolated
     */
    public boolean isIsolated()
    {
        return getCOSObject().getBoolean(COSName.I, false);
    }

    /**
     * Returns true if this group is a knockout. A knockout group blends with original backdrop, a non-knockout group
     * blends with the current backdrop.
     * 
     * @return true if this group is a knockout
     */
    public boolean isKnockout()
    {
        return getCOSObject().getBoolean(COSName.K, false);
    }
}

        if (colorSpace == null && getCOSObject().containsKey(COSName.CS))
        {
            colorSpace = PDColorSpace.create(getCOSObject().getDictionaryObject(COSName.CS), resources);
        }
        return colorSpace;
    
<no_super_class>