Amount representation.

Defer the conversion of amount strings into
BigDecimal until the point where they act as
numeric operands.

This saves resources because in several cases
the amount strings do not partecipate in any
calculation.  For example, an error might occur
before the calculation, or the calculation is
not carried at all by the function that gets
the amount string from the network.

2 files changed, 7 insertions, 6 deletions

diff --git a/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt b/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
index 17db9166..8f87c0e2 100644
--- a/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
+++ b/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
@@ -381,7 +381,7 @@ data class Pain001Data(
     val creditorIban: String,
     val creditorBic: String?,
     val creditorName: String,
-    val sum: Amount,
+    val sum: String,
     val currency: String,
     val subject: String
 )
@@ -418,7 +418,7 @@ class CurrencyAmountDeserializer(jc: Class<*> = CurrencyAmount::class.java) : St
         val s = p.valueAsString
         val components = s.split(":")
         // FIXME: error handling!
-        return CurrencyAmount(components[0], BigDecimal(components[1]))
+        return CurrencyAmount(components[0], components[1])
     }
 }
 
@@ -430,19 +430,20 @@ class CurrencyAmountSerializer(jc: Class<CurrencyAmount> = CurrencyAmount::class
         if (value == null) {
             gen.writeNull()
         } else {
-            gen.writeString("${value.currency}:${value.value.toPlainString()}")
+            gen.writeString("${value.currency}:${value.value}")
         }
     }
 }
 
+// FIXME: this type duplicates AmountWithCurrency.
 @JsonDeserialize(using = CurrencyAmountDeserializer::class)
 @JsonSerialize(using = CurrencyAmountSerializer::class)
 data class CurrencyAmount(
     val currency: String,
-    val value: BigDecimal // allows calculations
+    val value: String // allows calculations
 )
 fun CurrencyAmount.toPlainString(): String {
-    return "${this.currency}:${this.value.toPlainString()}"
+    return "${this.currency}:${this.value}"
 }
 
 data class InitiatedPayments(
diff --git a/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt b/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
index b39c72ec..23df07a5 100644
--- a/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
+++ b/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
@@ -208,7 +208,7 @@ val nexusApp: Application.() -> Unit = {
                 cause.httpStatusCode,
                 message = ErrorResponse(
                     code = TalerErrorCode.TALER_EC_LIBEUFIN_NEXUS_GENERIC_ERROR.code,
-                    hint = "EBICS protocol error",
+                    hint = "The EBICS communication with the bank failed: ${cause.ebicsTechnicalCode}",
                     detail = cause.reason,
                 )
             )