public void setFilename(String filename) throws Exception {
        if (null == filename) {
            throw new Exception("Must supply valid filename.");
        }
        try {
            this.stream = new FileInputStream(filename);
        } catch (FileNotFoundException e) {
            throw new Exception("height file not found: " + filename);
        }
    }
<code>setFilename</code> sets the file to use for the RAW data. A call
to <code>load</code> is required to put the changes into effect.

@param filename
           the new file to use for the height data.
@throws Exception
            if the file is null or not RAW.
jme3-terrain/src/main/java/com/jme3/terrain/heightmap/RawHeightMap.java