Replace mapToArray with Streams-based code (#739)

and you can now do (1..10).stream()...

core/src/main/kotlin/net/corda/core/Streams.kt

@@ -0,0 +1,30 @@
+package net.corda.core
+
+import java.util.*
+import java.util.Spliterator.*
+import java.util.stream.IntStream
+import java.util.stream.Stream
+import java.util.stream.StreamSupport
+import kotlin.streams.asSequence
+
+private fun IntProgression.spliteratorOfInt(): Spliterator.OfInt {
+    val kotlinIterator = iterator()
+    val javaIterator = object : PrimitiveIterator.OfInt {
+        override fun nextInt() = kotlinIterator.nextInt()
+        override fun hasNext() = kotlinIterator.hasNext()
+        override fun remove() = throw UnsupportedOperationException("remove")
+    }
+    val spliterator = Spliterators.spliterator(
+            javaIterator,
+            (1 + (last - first) / step).toLong(),
+            SUBSIZED or IMMUTABLE or NONNULL or SIZED or ORDERED or SORTED or DISTINCT
+    )
+    return if (step > 0) spliterator else object : Spliterator.OfInt by spliterator {
+        override fun getComparator() = Comparator.reverseOrder<Int>()
+    }
+}
+
+fun IntProgression.stream(): IntStream = StreamSupport.intStream(spliteratorOfInt(), false)
+
+@Suppress("UNCHECKED_CAST") // When toArray has filled in the array, the component type is no longer T? but T (that may itself be nullable).
+inline fun <reified T> Stream<out T>.toTypedArray() = toArray { size -> arrayOfNulls<T>(size) } as Array<T>

core/src/main/kotlin/net/corda/core/Utils.kt

@@ -24,7 +24,6 @@ import java.nio.file.*
 import java.nio.file.attribute.FileAttribute
 import java.time.Duration
 import java.time.temporal.Temporal
-import java.util.HashMap
 import java.util.concurrent.*
 import java.util.concurrent.locks.ReentrantLock
 import java.util.function.BiConsumer
@@ -111,16 +110,6 @@ fun <T> ListenableFuture<T>.andForget(log: Logger) = failure(RunOnCallerThread)
 infix fun <F, T> ListenableFuture<F>.map(mapper: (F) -> T): ListenableFuture<T> = Futures.transform(this, { (mapper as (F?) -> T)(it) })
 infix fun <F, T> ListenableFuture<F>.flatMap(mapper: (F) -> ListenableFuture<T>): ListenableFuture<T> = Futures.transformAsync(this) { mapper(it!!) }
 
-inline fun <T, reified R> Collection<T>.mapToArray(transform: (T) -> R) = mapToArray(transform, iterator(), size)
-inline fun <reified R> IntProgression.mapToArray(transform: (Int) -> R) = mapToArray(transform, iterator(), 1 + (last - first) / step)
-inline fun <T, reified R> mapToArray(transform: (T) -> R, iterator: Iterator<T>, size: Int) = run {
-    var expected = 0
-    Array(size) {
-        expected++ == it || throw UnsupportedOperationException("Array constructor is non-sequential!")
-        transform(iterator.next())
-    }
-}
-
 /** Executes the given block and sets the future to either the result, or any exception that was thrown. */
 inline fun <T> SettableFuture<T>.catch(block: () -> T) {
     try {

core/src/main/kotlin/net/corda/core/crypto/X509Utilities.kt

@@ -1,7 +1,6 @@
 package net.corda.core.crypto
 
 import net.corda.core.crypto.Crypto.generateKeyPair
-import net.corda.core.mapToArray
 import org.bouncycastle.asn1.ASN1Encodable
 import org.bouncycastle.asn1.x500.X500Name
 import org.bouncycastle.asn1.x500.X500NameBuilder

core/src/test/kotlin/net/corda/core/StreamsTest.kt

@@ -0,0 +1,42 @@
+package net.corda.core
+
+import org.junit.Assert.assertArrayEquals
+import org.junit.Test
+import java.util.stream.IntStream
+import java.util.stream.Stream
+import kotlin.test.assertEquals
+
+class StreamsTest {
+    @Test
+    fun `IntProgression stream works`() {
+        assertArrayEquals(intArrayOf(1, 2, 3, 4), (1..4).stream().toArray())
+        assertArrayEquals(intArrayOf(1, 2, 3, 4), (1 until 5).stream().toArray())
+        assertArrayEquals(intArrayOf(1, 3), (1..4 step 2).stream().toArray())
+        assertArrayEquals(intArrayOf(1, 3), (1..3 step 2).stream().toArray())
+        assertArrayEquals(intArrayOf(), (1..0).stream().toArray())
+        assertArrayEquals(intArrayOf(1, 0), (1 downTo 0).stream().toArray())
+        assertArrayEquals(intArrayOf(3, 1), (3 downTo 0 step 2).stream().toArray())
+        assertArrayEquals(intArrayOf(3, 1), (3 downTo 1 step 2).stream().toArray())
+    }
+
+    @Test
+    fun `IntProgression spliterator characteristics and comparator`() {
+        val rangeCharacteristics = IntStream.range(0, 2).spliterator().characteristics()
+        val forward = (0..9 step 3).stream().spliterator()
+        assertEquals(rangeCharacteristics, forward.characteristics())
+        assertEquals(null, forward.comparator)
+        val reverse = (9 downTo 0 step 3).stream().spliterator()
+        assertEquals(rangeCharacteristics, reverse.characteristics())
+        assertEquals(Comparator.reverseOrder(), reverse.comparator)
+    }
+
+    @Test
+    fun `Stream toTypedArray works`() {
+        val a: Array<String> = Stream.of("one", "two").toTypedArray()
+        assertEquals(Array<String>::class.java, a.javaClass)
+        assertArrayEquals(arrayOf("one", "two"), a)
+        val b: Array<String?> = Stream.of("one", "two", null).toTypedArray()
+        assertEquals(Array<String?>::class.java, b.javaClass)
+        assertArrayEquals(arrayOf("one", "two", null), b)
+    }
+}

core/src/test/kotlin/net/corda/core/crypto/X509NameConstraintsTest.kt

@@ -1,16 +1,16 @@
 package net.corda.core.crypto
 
-import net.corda.core.mapToArray
+import net.corda.core.toTypedArray
 import org.bouncycastle.asn1.x500.X500Name
 import org.bouncycastle.asn1.x509.GeneralName
 import org.bouncycastle.asn1.x509.GeneralSubtree
 import org.bouncycastle.asn1.x509.NameConstraints
-import org.bouncycastle.cert.X509CertificateHolder
 import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter
 import org.bouncycastle.jce.provider.BouncyCastleProvider
 import org.junit.Test
 import java.security.KeyStore
 import java.security.cert.*
+import java.util.stream.Stream
 import kotlin.test.assertFailsWith
 import kotlin.test.assertTrue
 
@@ -38,7 +38,7 @@ class X509NameConstraintsTest {
         val keyStore = KeyStore.getInstance(KeyStoreUtilities.KEYSTORE_TYPE)
         keyStore.load(null, keyPass.toCharArray())
         keyStore.addOrReplaceKey(X509Utilities.CORDA_CLIENT_TLS, tlsKey.private, keyPass.toCharArray(),
-                listOf(tlsCert, clientCACert, intermediateCACert, rootCACert).mapToArray<X509CertificateHolder, Certificate>(converter::getCertificate))
+                Stream.of(tlsCert, clientCACert, intermediateCACert, rootCACert).map(converter::getCertificate).toTypedArray<Certificate>())
         return Pair(keyStore, trustStore)
     }
 

core/src/test/kotlin/net/corda/core/crypto/X509UtilitiesTest.kt

@@ -5,14 +5,13 @@ import net.corda.core.crypto.Crypto.generateKeyPair
 import net.corda.core.crypto.X509Utilities.DEFAULT_TLS_SIGNATURE_SCHEME
 import net.corda.core.crypto.X509Utilities.createSelfSignedCACertificate
 import net.corda.core.div
-import net.corda.core.mapToArray
+import net.corda.core.toTypedArray
 import net.corda.testing.MEGA_CORP
 import net.corda.testing.getTestX509Name
 import org.bouncycastle.asn1.x500.X500Name
 import org.bouncycastle.asn1.x509.BasicConstraints
 import org.bouncycastle.asn1.x509.Extension
 import org.bouncycastle.asn1.x509.KeyUsage
-import org.bouncycastle.cert.X509CertificateHolder
 import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter
 import org.bouncycastle.operator.jcajce.JcaContentVerifierProviderBuilder
 import org.junit.Rule
@@ -21,7 +20,6 @@ import org.junit.rules.TemporaryFolder
 import java.io.DataInputStream
 import java.io.DataOutputStream
 import java.io.IOException
-import java.math.BigInteger
 import java.net.InetAddress
 import java.net.InetSocketAddress
 import java.nio.file.Path
@@ -31,6 +29,7 @@ import java.security.SecureRandom
 import java.security.cert.Certificate
 import java.security.cert.X509Certificate
 import java.util.*
+import java.util.stream.Stream
 import javax.net.ssl.*
 import kotlin.concurrent.thread
 import kotlin.test.*
@@ -94,7 +93,7 @@ class X509UtilitiesTest {
         // Save the EdDSA private key with self sign cert in the keystore.
         val keyStore = KeyStoreUtilities.loadOrCreateKeyStore(tmpKeyStore, "keystorepass")
         keyStore.setKeyEntry("Key", keyPair.private, "password".toCharArray(),
-                listOf(selfSignCert).mapToArray(converter::getCertificate))
+                Stream.of(selfSignCert).map(converter::getCertificate).toTypedArray())
         keyStore.save(tmpKeyStore, "keystorepass")
 
         // Load the keystore from file and make sure keys are intact.
@@ -120,7 +119,7 @@ class X509UtilitiesTest {
         val converter = JcaX509CertificateConverter()
         val keyStore = KeyStoreUtilities.loadOrCreateKeyStore(tmpKeyStore, "keystorepass")
         keyStore.setKeyEntry("Key", edDSAKeypair.private, "password".toCharArray(),
-                listOf(ecDSACert, edDSACert).mapToArray(converter::getCertificate))
+                Stream.of(ecDSACert, edDSACert).map(converter::getCertificate).toTypedArray())
         keyStore.save(tmpKeyStore, "keystorepass")
 
         // Load the keystore from file and make sure keys are intact.
@@ -360,7 +359,7 @@ class X509UtilitiesTest {
         keyStore.addOrReplaceKey(X509Utilities.CORDA_INTERMEDIATE_CA,
                 intermediateCAKeyPair.private,
                 keyPass,
-                listOf(intermediateCACert, rootCACert).mapToArray<X509CertificateHolder, Certificate>(converter::getCertificate))
+                Stream.of(intermediateCACert, rootCACert).map(converter::getCertificate).toTypedArray<Certificate>())
 
         keyStore.save(keyStoreFilePath, storePassword)
 

node/src/test/kotlin/net/corda/node/utilities/registration/NetworkisRegistrationHelperTest.kt

@@ -5,7 +5,7 @@ import com.nhaarman.mockito_kotlin.eq
 import com.nhaarman.mockito_kotlin.mock
 import net.corda.core.crypto.*
 import net.corda.core.exists
-import net.corda.core.mapToArray
+import net.corda.core.toTypedArray
 import net.corda.core.utilities.ALICE
 import net.corda.testing.TestNodeConfiguration
 import net.corda.testing.getTestX509Name
@@ -32,8 +32,8 @@ class NetworkRegistrationHelperTest {
                 "CORDA_ROOT_CA")
                 .map { getTestX509Name(it) }
         val converter = JcaX509CertificateConverter()
-        val certs = identities.map { X509Utilities.createSelfSignedCACertificate(it, Crypto.generateKeyPair(X509Utilities.DEFAULT_TLS_SIGNATURE_SCHEME)) }
+        val certs = identities.stream().map { X509Utilities.createSelfSignedCACertificate(it, Crypto.generateKeyPair(X509Utilities.DEFAULT_TLS_SIGNATURE_SCHEME)) }
-                .mapToArray(converter::getCertificate)
+                .map(converter::getCertificate).toTypedArray()
 
         val certService: NetworkRegistrationService = mock {
             on { submitRequest(any()) }.then { id }

samples/notary-demo/src/main/kotlin/net/corda/notarydemo/BFTNotaryCordform.kt

@@ -13,13 +13,14 @@ import net.corda.node.utilities.ServiceIdentityGenerator
 import net.corda.cordform.CordformDefinition
 import net.corda.cordform.CordformContext
 import net.corda.cordform.CordformNode
-import net.corda.core.mapToArray
+import net.corda.core.stream
+import net.corda.core.toTypedArray
 import net.corda.node.services.transactions.minCorrectReplicas
 import org.bouncycastle.asn1.x500.X500Name
 
 fun main(args: Array<String>) = BFTNotaryCordform.runNodes()
 
-private val clusterSize = 4 // Minimum size thats tolerates a faulty replica.
+private val clusterSize = 4 // Minimum size that tolerates a faulty replica.
 private val notaryNames = createNotaryNames(clusterSize)
 
 object BFTNotaryCordform : CordformDefinition("build" / "notary-demo-nodes", notaryNames[0]) {
@@ -38,7 +39,7 @@ object BFTNotaryCordform : CordformDefinition("build" / "notary-demo-nodes", not
             p2pPort(10005)
             rpcPort(10006)
         }
-        val clusterAddresses = (0 until clusterSize).mapToArray { HostAndPort.fromParts("localhost", 11000 + it * 10) }
+        val clusterAddresses = (0 until clusterSize).stream().mapToObj { HostAndPort.fromParts("localhost", 11000 + it * 10) }.toTypedArray()
         fun notaryNode(replicaId: Int, configure: CordformNode.() -> Unit) = node {
             name(notaryNames[replicaId])
             advertisedServices(advertisedService)

samples/notary-demo/src/main/kotlin/net/corda/notarydemo/Notarise.kt

@@ -14,6 +14,7 @@ import net.corda.core.transactions.SignedTransaction
 import net.corda.core.utilities.BOB
 import net.corda.notarydemo.flows.DummyIssueAndMove
 import net.corda.notarydemo.flows.RPCStartableNotaryFlowClient
+import kotlin.streams.asSequence
 
 fun main(args: Array<String>) {
     val address = HostAndPort.fromParts("localhost", 10003)
@@ -28,7 +29,8 @@ private class NotaryDemoClientApi(val rpc: CordaRPCOps) {
     private val notary by lazy {
         val (parties, partyUpdates) = rpc.networkMapUpdates()
         partyUpdates.notUsed()
-        parties.filter { it.advertisedServices.any { it.info.type.isNotary() } }.map { it.notaryIdentity }.distinct().single()
+        val id = parties.stream().filter { it.advertisedServices.any { it.info.type.isNotary() } }.map { it.notaryIdentity }.distinct().asSequence().singleOrNull()
+        checkNotNull(id) { "No unique notary identity, try cleaning the node directories." }
     }
 
     private val counterpartyNode by lazy {