8000 exceptions-to-values.5 : Introduce Result · java-to-kotlin/code@496c4c6 · GitHub
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Duncan McGregordmcg
Duncan McGregor
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dmcg
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exceptions-to-values.5 : Introduce Result
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‎build.gradle

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Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@ dependencies {
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implementation "com.fasterxml.jackson.core:jackson-databind:2.10.0"
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implementation "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.10.0"
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implementation "com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.10.0"
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implementation "com.natpryce:result4k:2.0.0"
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testImplementation "org.junit.jupiter:junit-jupiter-api:5.4.2"
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testImplementation "org.junit.jupiter:junit-jupiter-params:5.4.2"

‎src/main/java/travelator/marketing/HighValueCustomersReport.kt

Lines changed: 28 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -1,15 +1,20 @@
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package travelator.marketing
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import com.natpryce.Failure
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import com.natpryce.Result
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import com.natpryce.Success
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import com.natpryce.recover
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fun Sequence<String>.toHighValueCustomerReport(
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onErrorLine: (String) -> Unit = {}
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): Sequence<String> {
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val valuableCustomers = this
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.withoutHeader()
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.map { line ->
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val customerData = line.toCustomerData()
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if (customerData == null)
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line.toCustomerData().recover {
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onErrorLine(line)
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customerData
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null
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}
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}
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.filterNotNull()
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.filter { it.score >= 10 }
@@ -27,23 +32,33 @@ private fun List<CustomerData>.summarised(): String =
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private fun Sequence<String>.withoutHeader() = drop(1)
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internal fun String.toCustomerData(): CustomerData? =
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internal fun String.toCustomerData(): Result<CustomerData, ParseFailure> =
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split("\t").let { parts ->
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if (parts.size < 4)
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return null
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return Failure(NotEnoughFieldsFailure(this))
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val score = parts[3].toIntOrNull() ?:
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return null
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return Failure(ScoreIsNotAnIntFailure(this))
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val spend = if (parts.size == 4) 0.0 else parts[4].toDoubleOrNull() ?:
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return null
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CustomerData(
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id = parts[0],
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givenName = parts[1],
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familyName = parts[2],
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score = score,
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spend = spend
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return Failure(SpendIsNotADoubleFailure(this))
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Success(
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CustomerData(
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id = parts[0],
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givenName = parts[1],
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familyName = parts[2],
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score = score,
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spend = spend
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)
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)
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}
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sealed class ParseFailure(open val line: String)
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data class NotEnoughFieldsFailure(override val line: String) :
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ParseFailure(line)
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data class ScoreIsNotAnIntFailure(override val line: String) :
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ParseFailure(line)
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data class SpendIsNotADoubleFailure(override val line: String) :
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ParseFailure(line)
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private val CustomerData.outputLine: String
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get() = "$id\t$marketingName\t${spend.toMoneyString()}"
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‎src/test/java/travelator/marketing/HighValueCustomersReportTests.kt

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
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package travelator.marketing
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import com.natpryce.Success
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import org.junit.jupiter.api.Assertions.assertEquals
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import org.junit.jupiter.api.Test
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@@ -40,7 +41,7 @@ class HighValueCustomersReportTests {
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@Test
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fun emptySpendIs0() {
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assertEquals(
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CustomerData("1", "Fred", "Flintstone", 0, 0.0),
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Success(CustomerData("1", "Fred", "Flintstone", 0, 0.0)),
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"1\tFred\tFlintstone\t0".toCustomerData()
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)
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}

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