1 files changed, 47 insertions, 0 deletions
diff --git a/sources/hv-collector-utils/src/main/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/core.kt b/sources/hv-collector-utils/src/main/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/core.kt
new file mode 100644
index 00000000..7381592d
--- /dev/null
+++ b/sources/hv-collector-utils/src/main/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/core.kt
@@ -0,0 +1,47 @@
+/*
+ * ============LICENSE_START=======================================================
+ * dcaegen2-collectors-veshv
+ * ================================================================================
+ * Copyright (C) 2018 NOKIA
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.collectors.veshv.utils.arrow
+
+import arrow.core.Either
+import arrow.core.Option
+import arrow.core.identity
+import arrow.syntax.collections.firstOption
+import java.util.concurrent.atomic.AtomicReference
+
+/**
+ * @author Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
+ * @since July 2018
+ */
+
+fun <A> Either<A, A>.flatten() = fold(::identity, ::identity)
+
+fun <B> Either<Throwable, B>.rightOrThrow() = fold({ throw it }, ::identity)
+
+fun <A, B> Either<A, B>.rightOrThrow(mapper: (A) -> Throwable) = fold({ throw mapper(it) }, ::identity)
+
+fun <A> AtomicReference<A>.getOption() = Option.fromNullable(get())
+
+fun <A> Option.Companion.fromNullablesChain(firstValue: A?, vararg nextValues: () -> A?): Option<A> =
+        if (firstValue != null)
+            Option.just(firstValue)
+        else nextValues.asSequence()
+                .map { it() }
+                .filter { it != null }
+                .firstOption()