@Override
    public String transform(final String formUserId) {
        val stringBuilder = new StringBuilder();
        if (this.prefix != null) {
            stringBuilder.append(this.prefix);
        }
        stringBuilder.append(formUserId);
        if (this.suffix != null) {
            stringBuilder.append(this.suffix);
        }
        return stringBuilder.toString();
    }
Transform the user id by adding a prefix or suffix.

@author Howard Gilbert
@author Scott Battaglia
@since 3.3.6
core/cas-server-core-util-api/src/main/java/org/apereo/cas/util/transforms/PrefixSuffixPrincipalNameTransformer.java