From 90ed907a06c55e47b224b7ce36dacf1215d9bea2 Mon Sep 17 00:00:00 2001
From: Felipe Orozco <ferozco@users.noreply.github.com>
Date: Wed, 20 Nov 2019 13:27:27 -0500
Subject: [PATCH] Refaster rule to convert Stream.of() -> Stream.empty()
 (#1061)

Add Refaster rule to convert Stream.of() -> Stream.empty()
---
 .../baseline/refaster/StreamEmpty.java        | 35 ++++++++++++++++
 .../baseline/refaster/StreamEmptyTest.java    | 41 +++++++++++++++++++
 changelog/@unreleased/pr-1061.v2.yml          |  5 +++
 3 files changed, 81 insertions(+)
 create mode 100644 baseline-refaster-rules/src/main/java/com/palantir/baseline/refaster/StreamEmpty.java
 create mode 100644 baseline-refaster-rules/src/test/java/com/palantir/baseline/refaster/StreamEmptyTest.java
 create mode 100644 changelog/@unreleased/pr-1061.v2.yml

diff --git a/baseline-refaster-rules/src/main/java/com/palantir/baseline/refaster/StreamEmpty.java b/baseline-refaster-rules/src/main/java/com/palantir/baseline/refaster/StreamEmpty.java
new file mode 100644
index 000000000..3d19b1155
--- /dev/null
+++ b/baseline-refaster-rules/src/main/java/com/palantir/baseline/refaster/StreamEmpty.java
@@ -0,0 +1,35 @@
+/*
+ * (c) Copyright 2019 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+package com.palantir.baseline.refaster;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.util.stream.Stream;
+
+public final class StreamEmpty<T> {
+
+    @BeforeTemplate
+    Stream<T> streamNoParams() {
+        return Stream.of();
+    }
+
+    @AfterTemplate
+    Stream<T> streamEmpty() {
+        return Stream.empty();
+    }
+
+}
diff --git a/baseline-refaster-rules/src/test/java/com/palantir/baseline/refaster/StreamEmptyTest.java b/baseline-refaster-rules/src/test/java/com/palantir/baseline/refaster/StreamEmptyTest.java
new file mode 100644
index 000000000..48d737713
--- /dev/null
+++ b/baseline-refaster-rules/src/test/java/com/palantir/baseline/refaster/StreamEmptyTest.java
@@ -0,0 +1,41 @@
+/*
+ * (c) Copyright 2019 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+package com.palantir.baseline.refaster;
+
+import org.junit.Test;
+
+public class StreamEmptyTest {
+
+    @Test
+    public void test() {
+        RefasterTestHelper
+                .forRefactoring(StreamEmpty.class)
+                .withInputLines(
+                        "Test",
+                        "import java.util.*;",
+                        "import java.util.stream.Stream;",
+                        "public class Test {",
+                        "  Stream<Integer> i = Stream.of();",
+                        "}")
+                .hasOutputLines(
+                        "import java.util.*;",
+                        "import java.util.stream.Stream;",
+                        "public class Test {",
+                        "  Stream<Integer> i = Stream.empty();",
+                        "}");
+    }
+}
diff --git a/changelog/@unreleased/pr-1061.v2.yml b/changelog/@unreleased/pr-1061.v2.yml
new file mode 100644
index 000000000..f877e155b
--- /dev/null
+++ b/changelog/@unreleased/pr-1061.v2.yml
@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Add Refaster rule to convert Stream.of() -> Stream.empty()
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1061