From 72231250ed81e10d66bfe70701e64fa5fe50f712 Mon Sep 17 00:00:00 2001
From: Jon Bratseth <bratseth@yahoo-inc.com>
Date: Wed, 15 Jun 2016 23:09:44 +0200
Subject: Publish

---
 .../main/java/com/yahoo/collections/Tuple2.java    | 65 ++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 vespajlib/src/main/java/com/yahoo/collections/Tuple2.java

(limited to 'vespajlib/src/main/java/com/yahoo/collections/Tuple2.java')

diff --git a/vespajlib/src/main/java/com/yahoo/collections/Tuple2.java b/vespajlib/src/main/java/com/yahoo/collections/Tuple2.java
new file mode 100644
index 00000000000..4a817381f9c
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/collections/Tuple2.java
@@ -0,0 +1,65 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.collections;
+
+/**
+ * A representation of a pair of values, typically of different types.
+ *
+ * <p>
+ * This class is to avoid littering a class with thin wrapper objects for
+ * passing around e.g. the state of an operation and the result value. Using
+ * this class may be correct, but it is a symptom that you may want to redesign
+ * your code. (Should you pass mutable objects to the method instead? Create a
+ * new class and do the work inside that class instead? Etc.)
+ * </p>
+ *
+ * @author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
+ */
+public final class Tuple2<T1, T2> {
+
+    public final T1 first;
+    public final T2 second;
+
+    public Tuple2(final T1 first, final T2 second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    /**
+     * hashCode() will always throw UnsupportedOperationException. The reason is
+     * this class is not meant for being put in Container implementation or
+     * similar use where Java generics will lead to a type unsafe maintenance
+     * nightmare.
+     *
+     * @throws UnsupportedOperationException
+     *             will always throw this when invoked
+     */
+    @Override
+    public int hashCode() {
+        throw new UnsupportedOperationException(
+                "com.yahoo.collections.Tuple2<T1, T2> does not support equals(Object) by design. Refer to JavaDoc for details.");
+    }
+
+    /**
+     * equals(Object) will always throw UnsupportedOperationException. The
+     * intention is always using the objects contained in the tuple directly.
+     *
+     * @param obj
+     *            ignored
+     * @throws UnsupportedOperationException
+     *             will always throw this when invoked
+     */
+    @Override
+    public boolean equals(final Object obj) {
+        throw new UnsupportedOperationException(
+                "com.yahoo.collections.Tuple2<T1, T2> does not support equals(Object) by design. Refer to JavaDoc for details.");
+    }
+
+    /**
+     * Human readable string representation which invokes the contained
+     * instances' toString() implementation.
+     */
+    @Override
+    public String toString() {
+        return "Tuple2(" + first + ", " + second + ")";
+    }
+}
-- 
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