public void setModelType(int modelType) {
        switch(modelType) {
            case HEXADECIMAL : 
            case DECIMAL :
            case OCTAL :
            case BINARY :
            case ACSII :
            case RAW :
                this.modelType = modelType;
                
                // inform listeners of data change
                fireTableDataChanged();
                break;
            default :
                throw new IllegalArgumentException("Invalid model type");
        }
    }