PostalAddress in Kotlin

PostalAddress.kt

/**
 * Encapsulates a postal address.
 */
data class PostalAddress(
    val name: String? = null,
    val street1: String,
    val street2: String? = null,
    val street3: String? = null,
    val street4: String? = null,
    val city: String,
    val state: String,
    val postalCode: String) {

  fun toSingleLineStringForDisplay(): String {
    val sb = StringBuilder()
    sb.append(street1).append(", ")
    if (street2 != null) {
      sb.append(street2).append(", ")
    }
    if (street3 != null) {
      sb.append(street3).append(", ")
    }
    if (street4 != null) {
      sb.append(street4).append(", ")
    }
    sb.append(city).append(", ")
        .append(state).append(" ")
        .append(postalCode)
    return sb.toString()
  }
}