8230337: Clarify intention of Elements.{getPackageOf, getModuleOf}

Reviewed-by: jjg

src/java.compiler/share/classes/javax/lang/model/util/Elements.java

@@ -453,30 +453,45 @@ default boolean isBridge(ExecutableElement e) {
      * itself.
      * The package of a module is {@code null}.
      *
-     * @param type the element being examined
+     * The package of a top-level type is its {@linkplain
+     * TypeElement#getEnclosingElement enclosing package}. Otherwise,
+     * the package of an element is equal to the package of the
+     * {@linkplain Element#getEnclosingElement enclosing element}.
+     *
+     * @param e the element being examined
      * @return the package of an element
      */
-    PackageElement getPackageOf(Element type);
+    PackageElement getPackageOf(Element e);
 
     /**
      * Returns the module of an element.  The module of a module is
      * itself.
-     * If there is no module for the element, null is returned. One situation where there is
-     * no module for an element is if the environment does not include modules, such as
-     * an annotation processing environment configured for
-     * a {@linkplain
+     *
+     * If a package has a module as its {@linkplain
+     * PackageElement#getEnclosingElement enclosing element}, that
+     * module is the module of the package. If the enclosing element
+     * of a package is {@code null}, {@code null} is returned for the
+     * package's module.
+     *
+     * (One situation where a package may have a {@code null} module
+     * is if the environment does not include modules, such as an
+     * annotation processing environment configured for a {@linkplain
      * javax.annotation.processing.ProcessingEnvironment#getSourceVersion
-     * source version} without modules.
+     * source version} without modules.)
+     *
+     * Otherwise, the module of an element is equal to the module
+     * {@linkplain #getPackageOf(Element) of the package} of the
+     * element.
      *
      * @implSpec The default implementation of this method returns
      * {@code null}.
      *
-     * @param type the element being examined
+     * @param e the element being examined
      * @return the module of an element
      * @since 9
      * @spec JPMS
      */
-    default ModuleElement getModuleOf(Element type) {
+    default ModuleElement getModuleOf(Element e) {
         return null;
     }
 

test/langtools/tools/javac/processing/model/util/elements/TestGetModuleOf.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2006, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8230337
+ * @summary Test Elements.getModuleOf
+ * @library /tools/javac/lib
+ * @modules java.compiler
+ *          jdk.compiler
+ * @build   JavacTestingAbstractProcessor TestGetModuleOf
+ * @compile -processor TestGetModuleOf -proc:only TestGetModuleOf.java
+ * @compile -processor TestGetModuleOf -proc:only -source 8 -Xlint:-options TestGetModuleOf.java
+ */
+
+// Also run test under -source 8 to test old behavior pre-modules.
+
+import java.util.*;
+import javax.annotation.processing.*;
+import javax.lang.model.SourceVersion;
+import static javax.lang.model.SourceVersion.*;
+import javax.lang.model.element.*;
+import javax.lang.model.util.*;
+import static javax.lang.model.util.ElementFilter.*;
+import static javax.tools.Diagnostic.Kind.*;
+import static javax.tools.StandardLocation.*;
+
+/**
+ * Test basic workings of Elements.getModuleOf
+ */
+public class TestGetModuleOf extends JavacTestingAbstractProcessor {
+    /**
+     * Check expected behavior on classes and packages and other elements.
+     */
+    public boolean process(Set<? extends TypeElement> annotations,
+                           RoundEnvironment roundEnv) {
+        if (!roundEnv.processingOver()) {
+            TypeElement    charElt     = eltUtils.getTypeElement("java.lang.Character");
+            PackageElement javaLangPkg = eltUtils.getPackageElement("java.lang");
+            ModuleElement  expectedMod = enclosingToModule(javaLangPkg);
+
+            checkMod(charElt, expectedMod);
+            checkMod(javaLangPkg, expectedMod);
+
+            // The module of fields and methods and nested types of
+            // java.lang.Character should match the module of
+            // java.lang.
+            for (Element e : charElt.getEnclosedElements()) {
+                checkMod(e, expectedMod);
+            }
+
+            // A module of a module is itself
+            if (expectedMod != null)
+                checkMod(expectedMod, expectedMod);
+        }
+        return true;
+    }
+
+    private ModuleElement enclosingToModule(Element e) {
+        Element enclosing = e.getEnclosingElement();
+        if (enclosing == null)
+            return null;
+        else
+            return ElementFilter.modulesIn(List.of(enclosing)).get(0);
+    }
+
+    private void checkMod(Element e, ModuleElement expectedMod) {
+        ModuleElement actualMod = eltUtils.getModuleOf(e);
+        if (!Objects.equals(actualMod, expectedMod)) {
+            throw new RuntimeException(String.format("Unexpected module ``%s''' for %s %s, expected ``%s''%n",
+                                                     actualMod, e.getKind(), e.toString(), expectedMod));
+        }
+    }
+}

test/langtools/tools/javac/processing/model/util/elements/TestGetPackageOf.java

@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 6453386 8216404
+ * @bug 6453386 8216404 8230337
  * @summary Test Elements.getPackageOf
  * @author  Joseph D. Darcy
  * @library /tools/javac/lib
@@ -33,7 +33,7 @@
  * @compile -processor TestGetPackageOf -proc:only TestGetPackageOf.java
  */
 
-import java.util.Set;
+import java.util.*;
 import javax.annotation.processing.*;
 import javax.lang.model.SourceVersion;
 import static javax.lang.model.SourceVersion.*;
@@ -48,30 +48,41 @@
  */
 public class TestGetPackageOf extends JavacTestingAbstractProcessor {
     /**
-     * Check expected behavior on classes and packages.
+     * Check expected behavior on classes and packages and other elements.
      */
     public boolean process(Set<? extends TypeElement> annotations,
                            RoundEnvironment roundEnv) {
         if (!roundEnv.processingOver()) {
-            TypeElement    stringElt   = eltUtils.getTypeElement("java.lang.String");
+            TypeElement    charElt     = eltUtils.getTypeElement("java.lang.Character");
             PackageElement javaLangPkg = eltUtils.getPackageElement("java.lang");
             PackageElement unnamedPkg  = eltUtils.getPackageElement("");
-            ModuleElement  moduleElt   = eltUtils.getModuleElement("java.base");
-            PackageElement pkg = null;
 
-            if (!javaLangPkg.equals(pkg=eltUtils.getPackageOf(stringElt) ) )
-                throw new RuntimeException("Unexpected package for String: " + pkg);
+            Map<Element, PackageElement> testCases =
+                Map.of(javaLangPkg, javaLangPkg,
+                       charElt,     javaLangPkg,
+                       unnamedPkg,  unnamedPkg);
 
-            if (!javaLangPkg.equals(pkg=eltUtils.getPackageOf(javaLangPkg) ) )
-                throw new RuntimeException("Unexpected package for java.lang: " + pkg);
+            for (var testCase : testCases.entrySet()) {
+                checkPkg(testCase.getKey(), testCase.getValue());
+            }
 
-            if (!unnamedPkg.equals(pkg=eltUtils.getPackageOf(unnamedPkg) ) )
-                throw new RuntimeException("Unexpected package for unnamed pkg: " + pkg);
+            // The package of fields and methods and nested types of
+            // java.lang.Character is java.lang.
+            for (Element e : charElt.getEnclosedElements()) {
+                checkPkg(e, javaLangPkg);
+            }
 
-            if (eltUtils.getPackageOf(moduleElt) != null)
-                throw new RuntimeException("Unexpected package for module" +
-                                           moduleElt.getSimpleName());
+            // A module has a null package.
+            checkPkg(eltUtils.getModuleElement("java.base"), null);
         }
         return true;
     }
+
+    private void checkPkg(Element e, PackageElement expectedPkg) {
+        PackageElement actualPkg = eltUtils.getPackageOf(e);
+        if (!Objects.equals(actualPkg, expectedPkg)) {
+            throw new RuntimeException(String.format("Unexpected package ``%s''' for %s %s, expected ``%s''%n",
+                                                     actualPkg, e.getKind(), e.toString(), expectedPkg));
+        }
+    }
 }