feat: support jpms in annotations module

- feat: add `module-info.java` to `annotations`
- chore: wire up build support for building `java9` root in MRJAR
- chore: apply java9 jpms changes to both maven and makefile build

Signed-off-by: Sam Gammon <[email protected]>

Author: sgammon

annotations/.classpath

@@ -3,5 +3,5 @@
 	<classpathentry kind="src" path="src/main/java"/>
 	<classpathentry kind="lib" path="build_result/j2objc_annotations.jar"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
-  <classpathentry kind="output" path="build_result/eclipse"/>
+	<classpathentry kind="output" path="build_result/eclipse"/>
 </classpath>

annotations/.gitignore

@@ -0,0 +1 @@
+/target

annotations/Makefile

@@ -25,17 +25,26 @@ DIST_JAR = $(DIST_JAR_DIR)/$(JAR_NAME)
 
 CLASSES_DIR = $(BUILD_DIR)/classes
 JAVA_SOURCE_DIR = src/main/java
+JAVA9_CLASSES_DIR = $(BUILD_DIR)/classes-java9
+JPMS_CLASS = $(JAVA9_CLASSES_DIR)/module-info.class
 
 SOURCE_JAVA_FULL = $(ANNOTATION_SOURCE_JAVA:%=$(JAVA_SOURCE_DIR)/%)
+SOURCE_JAVA9_MODULE = $(ANNOTATION_MODULE_INFO:%=$(JAVA_SOURCE_DIR)/%)
 
-$(BUILD_DIR) $(CLASSES_DIR) $(DIST_JAR_DIR):
+$(BUILD_DIR) $(CLASSES_DIR) $(JAVA9_CLASSES_DIR) $(DIST_JAR_DIR):
 	@mkdir -p $@
 
-$(JAR): $(SOURCE_JAVA_FULL) | $(BUILD_DIR) $(CLASSES_DIR)
+$(JPMS_CLASS):
+	@echo Building j2objc annotations JPMS module
+	@$(JAVAC) -sourcepath $(JAVA_SOURCE_DIR) -encoding UTF-8 --release 9 -d $(JAVA9_CLASSES_DIR) \
+		-nowarn $(SOURCE_JAVA9_MODULE)
+	@rm -fr $(JAVA9_CLASSES_DIR)/com
+
+$(JAR): $(SOURCE_JAVA_FULL) | $(BUILD_DIR) $(CLASSES_DIR) $(JAVA9_CLASSES_DIR) $(JPMS_CLASS)
 	@echo Building j2objc annotations
 	@$(JAVAC) -encoding UTF-8 -d $(CLASSES_DIR) -source 1.8 -target 1.8 \
 	    -nowarn $^
-	@jar cf $(JAR) -C $(CLASSES_DIR) .
+	@jar cf $(JAR) -C $(CLASSES_DIR) . --release 9 -C $(JAVA9_CLASSES_DIR) .
 
 $(DIST_JAR): $(JAR) | $(DIST_JAR_DIR)
 	@install -m 0644 $< $@

annotations/classes.mk

@@ -10,6 +10,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+ANNOTATION_MODULE_INFO = \
+    module-info.java
+
 ANNOTATION_SOURCE_JAVA = \
     com/google/j2objc/annotations/AutoreleasePool.java \
     com/google/j2objc/annotations/GenerateObjectiveCGenerics.java \

annotations/pom.xml

@@ -58,6 +58,49 @@
 
   <build>
     <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.12.1</version>
+        <executions>
+          <execution>
+            <id>default-compile</id>
+            <configuration>
+              <source>1.8</source>
+              <target>1.8</target>
+              <excludes>
+                <exclude>module-info.java</exclude>
+              </excludes>
+            </configuration>
+          </execution>
+          <execution>
+            <id>compile-java9</id>
+            <phase>compile</phase>
+            <goals>
+              <goal>compile</goal>
+            </goals>
+            <configuration>
+              <release>9</release>
+              <multiReleaseOutput>true</multiReleaseOutput>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>3.3.0</version>
+        <configuration>
+          <archive>
+            <manifestEntries>
+              <Multi-Release>true</Multi-Release>
+            </manifestEntries>
+          </archive>
+          <excludes>
+            <exclude>META-INF/versions/9/com/**</exclude>
+          </excludes>
+        </configuration>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>

annotations/src/main/java/module-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012 Google 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.
+ */
+
+open module com.google.j2objc.annotations {
+  requires java.base;
+  exports com.google.j2objc.annotations;
+}