public static boolean multiplicityMatch(VariableMapping mapping) {
        String leftMult = mapping.getLeftVariable().getMultiplicity();
        String rightMult = mapping.getRightVariable().getMultiplicity();
        
        if(leftMult == null){
            if(rightMult != null){
                return false;
            }
        }else{
            if(rightMult == null){
                return false;
            }else{
                if(!leftMult.equalsIgnoreCase(rightMult)){
                    return false;
                }
            }
        }
        return true;
    }
Check if a mapping is valid by checking the multiplicity of both of
the variables if they are arrays

@param mapping the mapping
@return true if this mapping is valid
jme3-core/src/main/java/com/jme3/shader/ShaderUtils.java