1 files changed, 69 insertions, 0 deletions
diff --git a/third_party/checker_framework_javacutil/java/org/checkerframework/javacutil/Pair.java b/third_party/checker_framework_javacutil/java/org/checkerframework/javacutil/Pair.java
new file mode 100644
index 0000000000..0d8a862f08
--- /dev/null
+++ b/third_party/checker_framework_javacutil/java/org/checkerframework/javacutil/Pair.java
@@ -0,0 +1,69 @@
+package org.checkerframework.javacutil;
+
+/*>>>
+import org.checkerframework.dataflow.qual.Pure;
+import org.checkerframework.dataflow.qual.SideEffectFree;
+*/
+
+/**
+ * Simple pair class for multiple returns.
+ *
+ * TODO: as class is immutable, use @Covariant annotation.
+ */
+public class Pair<V1, V2> {
+    public final V1 first;
+    public final V2 second;
+
+    private Pair(V1 v1, V2 v2) {
+        this.first = v1;
+        this.second = v2;
+    }
+
+    public static <V1, V2> Pair<V1, V2> of(V1 v1, V2 v2) {
+        return new Pair<V1, V2>(v1, v2);
+    }
+
+    /*@SideEffectFree*/
+    @Override
+    public String toString() {
+        return "Pair(" + first + ", " + second + ")";
+    }
+
+    private int hashCode = -1;
+
+    /*@Pure*/
+    @Override
+    public int hashCode() {
+        if (hashCode == -1) {
+            hashCode = 31;
+            if (first != null) {
+                hashCode += 17 * first.hashCode();
+            }
+            if (second != null) {
+                hashCode += 17 * second.hashCode();
+            }
+        }
+        return hashCode;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof Pair)) {
+            return false;
+        }
+        @SuppressWarnings("unchecked")
+        Pair<V1, V2> other = (Pair<V1, V2>) o;
+        if (this.first == null) {
+            if (other.first != null) return false;
+        } else {
+            if (!this.first.equals(other.first)) return false;
+        }
+        if (this.second == null) {
+            if (other.second != null) return false;
+        } else {
+            if (!this.second.equals(other.second)) return false;
+        }
+
+        return true;
+    }
+}