[refactor] make Java embed utils generic

core/src/main/java/org/jruby/ir/instructions/RuntimeHelperCall.java

@@ -29,8 +29,10 @@ public enum Methods {
         IS_DEFINED_CLASS_VAR, IS_DEFINED_SUPER, IS_DEFINED_METHOD, IS_DEFINED_CALL,
         IS_DEFINED_CONSTANT_OR_METHOD, MERGE_KWARGS, IS_HASH_EMPTY, HASH_CHECK, ARRAY_LENGTH;
 
-        public static Methods fromOrdinal(int value) {
-            return value < 0 || value >= values().length ? null : values()[value];
+        private static final Methods[] VALUES = values();
+
+        static Methods fromOrdinal(int value) {
+            return value < 0 || value >= VALUES.length ? null : VALUES[value];
         }
     }
 

core/src/main/java/org/jruby/javasupport/JavaEmbedUtils.java

@@ -43,20 +43,24 @@
 import org.jruby.runtime.Block;
 import org.jruby.runtime.Helpers;
 import org.jruby.runtime.builtin.IRubyObject;
-import org.jruby.util.UriLikePathHelper;
 
 /**
- * Utility functions to help embedders out.   These function consolidate logic that is
- * used between BSF and JSR 223.  People who are embedding JRuby 'raw' should use these
- * as well.  If at a later date, we discover a flaw or change how we do things, this
- * utility class should provide some insulation.
+ * Utility functions to help embedders out.
+ * These function consolidate logic that is used between BSF and JSR 223.
+ * People who are embedding JRuby 'raw' should use these as well.
+ * If at a later date, we discover a flaw or change how we do things, this utility class should provide some insulation.
  *
+ * <pre>
  * Example:
- * Ruby runtime = JavaEmbedUtils.initialize(new ArrayList());
- * RubyRuntimeAdapter evaler = JavaEmbedUtils.newRuntimeAdapter();
- * IRubyObject rubyObject = evaler.parse(runtime, expr.toString(), file, line).run());
- * SomeClassOrInterface javaObject = (SomeClassOrInterface) JavaEmbedUtils.rubyToJava(rubyObject);
- * runtime.terminate();
+ *
+ *   Ruby runtime = JavaEmbedUtils.initialize(List.of("a/custom/load/path"));
+ *
+ *   RubyRuntimeAdapter evaler = JavaEmbedUtils.newRuntimeAdapter();
+ *   IRubyObject rubyObject = evaler.parse(runtime, expr.toString(), file, line).run());
+ *   SomeClassOrInterface javaObject = JavaEmbedUtils.rubyToJava(rubyObject, SomeClassOrInterface.class);
+ *
+ *   runtime.terminate();
+ * </pre>
  */
 public class JavaEmbedUtils {
     /**
@@ -223,7 +227,7 @@ public static void terminate(Ruby runtime) {
      * @return the result of the invocation.
      */
     @SuppressWarnings("deprecation")
-    public static Object invokeMethod(Ruby runtime, Object receiver, String method, Object[] args, Class returnType) {
+    public static <T> T invokeMethod(Ruby runtime, Object receiver, String method, Object[] args, Class<T> returnType) {
         IRubyObject rubyReceiver = receiver != null ? JavaUtil.convertJavaToRuby(runtime, receiver) : runtime.getTopSelf();
 
         IRubyObject[] rubyArgs = JavaUtil.convertJavaArrayToRuby(runtime, args);
@@ -243,7 +247,12 @@ public static Object invokeMethod(Ruby runtime, Object receiver, String method,
     /**
      * Convert a Ruby object to a Java object.
      */
-    public static Object rubyToJava(Ruby runtime, IRubyObject value, Class type) {
+    public static <T> T rubyToJava(IRubyObject value, Class<T> type) {
+        return value.toJava(type);
+    }
+
+    // @Deprecated
+    public static <T> T rubyToJava(Ruby runtime, IRubyObject value, Class<T> type) {
         return value.toJava(type);
     }
 
@@ -252,17 +261,15 @@ public static Object rubyToJava(Ruby runtime, IRubyObject value, Class type) {
      * @param value to be converted
      * @return the converted object
      */
-    public static Object rubyToJava(IRubyObject value) {
-        return value.toJava(Object.class);
+    public static <T> T rubyToJava(IRubyObject value) {
+        return (T) value.toJava(Object.class);
     }
 
     /**
      *  Convert a java object to a Ruby object.
      */
     @SuppressWarnings("deprecation")
     public static IRubyObject javaToRuby(Ruby runtime, Object value) {
-        if (value instanceof IRubyObject) return (IRubyObject) value;
-
         IRubyObject result = JavaUtil.convertJavaToUsableRubyObject(runtime, value);
 
         return result instanceof JavaObject ? Java.wrap(runtime, result) : result;

core/src/test/java/org/jruby/javasupport/JavaEmbedUtilsTest.java

@@ -3,14 +3,20 @@
 import java.io.File;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import org.jruby.java.proxies.ConcreteJavaProxy;
+import org.jruby.java.proxies.JavaProxy;
+import org.jruby.runtime.builtin.IRubyObject;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -65,4 +71,90 @@ public void testAddClassloaderToLoadPathOnNoneTCCL() throws Exception {
         String result = runtime.evalScriptlet("require 'test_me';$result").toString();
         assertEquals(result, "uri:" + url);
     }
+
+    @Test
+    public void testAPIUsageTheNonGenericWay() { // before <T> generic signatures were introduced (JRuby <= 9.4.0)
+        final Ruby runtime = Ruby.newInstance();
+        IRubyObject str = runtime.evalScriptlet("'foo'");
+        Object javaStr = JavaEmbedUtils.rubyToJava(runtime, str, String.class);
+        assertEquals("foo", javaStr);
+
+        str = runtime.evalScriptlet("'bar' * 3");
+        javaStr = JavaEmbedUtils.rubyToJava(runtime, str, Object.class);
+        assertEquals("barbarbar", javaStr);
+
+        Object val = JavaEmbedUtils.rubyToJava(runtime.newEmptyArray());
+        assertEquals("org.jruby.RubyArray", val.getClass().getName());
+    }
+
+    @Test
+    public void testJavaToRubyPrimitive() {
+        final Ruby runtime = Ruby.newInstance();
+
+        IRubyObject v;
+        v = JavaEmbedUtils.javaToRuby(runtime, -100L);
+        assertEquals(runtime.newFixnum(-100), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, 200);
+        assertEquals(runtime.newFixnum(200), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, (short) 200);
+        assertEquals(runtime.newFixnum(200), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, (byte) 100);
+        assertEquals(runtime.newFixnum(100), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, 10.0f);
+        assertEquals(runtime.newFloat(10.0), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, 10.0d);
+        assertEquals(runtime.newFloat(10.0), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, true);
+        assertSame(runtime.getTrue(), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, false);
+        assertSame(runtime.getFalse(), v);
+    }
+
+    @Test
+    public void testJavaToRuby() {
+        final Ruby runtime = Ruby.newInstance();
+
+        IRubyObject v;
+        v = JavaEmbedUtils.javaToRuby(runtime, "");
+        assertEquals(runtime.newString(), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, Long.valueOf(42L));
+        assertEquals(runtime.newFixnum(42), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, Boolean.TRUE);
+        assertSame(runtime.getTrue(), v);
+
+        v = JavaEmbedUtils.javaToRuby(runtime, new StringBuilder());
+        assertEquals(ConcreteJavaProxy.class, v.getClass()); // no more JavaObject wrapping!
+    }
+
+    @Test
+    public void testRubyToJava() {
+        final Ruby runtime = Ruby.newInstance();
+
+        CharSequence sym = JavaEmbedUtils.rubyToJava(runtime.newSymbol("foo"), CharSequence.class);
+        assertEquals("foo", sym);
+    }
+
+    @Test
+    public void testJavaToRubyAndRubyToJava() {
+        final Ruby runtime = Ruby.newInstance();
+
+        IRubyObject v = JavaEmbedUtils.javaToRuby(runtime, new ArrayList<>(Arrays.asList("1", '2', 3)));
+        assertTrue(v instanceof JavaProxy);
+        List<?> val = JavaEmbedUtils.rubyToJava(v);
+        assertEquals(3, val.size());
+
+        assertEquals(java.util.ArrayList.class, val.getClass());
+
+        Collection<Object> coll = JavaEmbedUtils.rubyToJava(v, Collection.class);
+        assertSame(val, coll);
+    }
 }