Add utility methods within auto-common to determine which @Generated annotation to use.
Add JavaPoet-specific utility methods for JavaPoet users.
RELNOTES=Add utility methods for writing `@Generated` annotations.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=178001124
diff --git a/common/pom.xml b/common/pom.xml
index 096f328..a2a0a8b 100644
--- a/common/pom.xml
+++ b/common/pom.xml
@@ -43,6 +43,14 @@
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
</dependency>
+ <dependency>
+ <!-- Used only by GeneratedAnnotationSpecs.
+ If you use JavaPoet, you can use GeneratedAnnotationSpecs. -->
+ <groupId>com.squareup</groupId>
+ <artifactId>javapoet</artifactId>
+ <optional>true</optional>
+ </dependency>
+
<!-- test dependencies -->
<dependency>
<groupId>com.google.guava</groupId>
diff --git a/common/src/main/java/com/google/auto/common/GeneratedAnnotationSpecs.java b/common/src/main/java/com/google/auto/common/GeneratedAnnotationSpecs.java
new file mode 100644
index 0000000..a4694ef
--- /dev/null
+++ b/common/src/main/java/com/google/auto/common/GeneratedAnnotationSpecs.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2017 Google, Inc.
+ *
+ * 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.google.auto.common;
+
+import com.squareup.javapoet.AnnotationSpec;
+import com.squareup.javapoet.ClassName;
+import java.util.Optional;
+import javax.lang.model.util.Elements;
+
+/** Utility methods for writing {@code @Generated} annotations using JavaPoet. */
+public final class GeneratedAnnotationSpecs {
+
+ private GeneratedAnnotationSpecs() {}
+
+ /**
+ * Returns {@code @Generated("processorClass"} if either {@code
+ * javax.annotation.processing.Generated} or {@code javax.annotation.Generated} is {@linkplain
+ * GeneratedAnnotations#generatedAnnotation(Elements) available at compile time}.
+ */
+ public static Optional<AnnotationSpec> generatedAnnotationSpec(
+ Elements elements, Class<?> processorClass) {
+ return generatedAnnotationSpecBuilder(elements, processorClass)
+ .map(AnnotationSpec.Builder::build);
+ }
+
+ /**
+ * Returns {@code @Generated(value = "processorClass", comments = "comments"} if either {@code
+ * javax.annotation.processing.Generated} or {@code javax.annotation.Generated} is {@linkplain
+ * GeneratedAnnotations#generatedAnnotation(Elements) available at compile time}.
+ */
+ public static Optional<AnnotationSpec> generatedAnnotationSpec(
+ Elements elements, Class<?> processorClass, String comments) {
+ return generatedAnnotationSpecBuilder(elements, processorClass)
+ .map(annotation -> annotation.addMember("comments", "$S", comments).build());
+ }
+
+ private static Optional<AnnotationSpec.Builder> generatedAnnotationSpecBuilder(
+ Elements elements, Class<?> processorClass) {
+ return GeneratedAnnotations.generatedAnnotation(elements)
+ .map(
+ generated ->
+ AnnotationSpec.builder(ClassName.get(generated))
+ .addMember("value", "$S", processorClass.getCanonicalName()));
+ }
+}
diff --git a/common/src/main/java/com/google/auto/common/GeneratedAnnotations.java b/common/src/main/java/com/google/auto/common/GeneratedAnnotations.java
new file mode 100644
index 0000000..1a5f089
--- /dev/null
+++ b/common/src/main/java/com/google/auto/common/GeneratedAnnotations.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Google, Inc.
+ *
+ * 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.google.auto.common;
+
+import java.util.Optional;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.util.Elements;
+
+/** Utility methods for writing {@code @Generated} annotations. */
+public final class GeneratedAnnotations {
+ private GeneratedAnnotations() {}
+
+ /**
+ * Returns the element corresponding to the version of the {@code @Generated} annotation present
+ * in the compile-time class- or module-path.
+ *
+ * <p>First looks for {@code javax.annotation.processing.Generated}, and then {@code
+ * javax.annotation.Generated}. Returns whichever is in the classpath (or modulepath), or {@link
+ * Optional#empty()} if neither is.
+ */
+ public static Optional<TypeElement> generatedAnnotation(Elements elements) {
+ TypeElement jdk9Generated = elements.getTypeElement("javax.annotation.processing.Generated");
+ if (jdk9Generated != null) {
+ return Optional.of(jdk9Generated);
+ }
+ return Optional.ofNullable(elements.getTypeElement("javax.annotation.Generated"));
+ }
+}
