@Override
    public String toString() {
        if (value != null) {
            return type.name() + " " + name + " : " + getValueAsString();
        } else {
            return type.name() + " " + name;
        }
    }
Returns the material parameter value as it would appear in a J3M
file. E.g.
<pre>
MaterialParameters {
    ABC : 1 2 3 4
}
</pre>
Assuming "ABC" is a Vector4 parameter, then the value
"1 2 3 4" would be returned by this method.

@return material parameter value as it would appear in a J3M file.
jme3-core/src/main/java/com/jme3/material/MatParam.java