Adds the source of the checker framework

This needs to predate the rest of the changes to the checker framework to keep the build green.

Also add the source of javacutil part of the checker framework, that will be included in the next change.

Change-Id: Ie18d0e8e21035ce5141416e552a83d893f71b88b

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;
+    }
+}