Add support for object arrays.

gojni.h

@@ -37,6 +37,9 @@ __attribute__ ((visibility ("hidden"))) jlong _jni_CallLongMethodA(JNIEnv *env,
 __attribute__ ((visibility ("hidden"))) jfloat _jni_CallFloatMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) jdouble _jni_CallDoubleMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args);
 __attribute__ ((visibility ("hidden"))) jbyteArray _jni_NewByteArray(JNIEnv *env, jsize length);
+__attribute__ ((visibility ("hidden"))) jobjectArray _jni_NewObjectArray(JNIEnv *env, jsize length, jclass elementClass, jobject initialElement);
+__attribute__ ((visibility ("hidden"))) jobject _jni_GetObjectArrayElement(JNIEnv *env, jobjectArray array, jsize index);
+__attribute__ ((visibility ("hidden"))) void _jni_SetObjectArrayElement(JNIEnv *env, jobjectArray array, jsize index, jobject value);
 __attribute__ ((visibility ("hidden"))) jbyte *_jni_GetByteArrayElements(JNIEnv *env, jbyteArray arr);
 __attribute__ ((visibility ("hidden"))) void _jni_ReleaseByteArrayElements(JNIEnv *env, jbyteArray arr, jbyte *elems, jint mode);
 __attribute__ ((visibility ("hidden"))) jsize _jni_GetArrayLength(JNIEnv *env, jarray arr);

jni.c

@@ -178,6 +178,18 @@ jsize _jni_GetArrayLength(JNIEnv *env, jarray arr) {
 	return (*env)->GetArrayLength(env, arr);
 }
 
+jobjectArray _jni_NewObjectArray(JNIEnv *env, jsize length, jclass elementClass, jobject initialElement) {
+	return (*env)->NewObjectArray(env, length, elementClass, initialElement);
+}
+
+jobject _jni_GetObjectArrayElement(JNIEnv *env, jobjectArray array, jsize index) {
+  return (*env)->GetObjectArrayElement(env, array, index);
+}
+
+void _jni_SetObjectArrayElement(JNIEnv *env, jobjectArray array, jsize index, jobject value) {
+  return (*env)->SetObjectArrayElement(env, array, index, value);
+}
+
 jobject _jni_GetStaticObjectField(JNIEnv *env, jclass clazz, jfieldID fieldID) {
     return (*env)->GetStaticObjectField(env, clazz, fieldID);
 }

jni.go

@@ -39,6 +39,8 @@ type (
 	FieldID     C.jfieldID
 	String      C.jstring
 	ByteArray   C.jbyteArray
+	ObjectArray C.jobjectArray
+	Size        C.jsize
 	Value       uint64 // All JNI types fit into 64-bits.
 )
 
@@ -221,6 +223,28 @@ func NewByteArray(e Env, content []byte) ByteArray {
 	return ByteArray(jarr)
 }
 
+func NewObjectArray(e Env, len Size, class Class, elem Object) ObjectArray {
+	jarr := C._jni_NewObjectArray(e.env, C.jsize(len), C.jclass(class), C.jobject(elem))
+	if jarr == 0 {
+		panic(fmt.Errorf("jni: NewObjectArray failed"))
+	}
+	return ObjectArray(jarr)
+}
+
+func GetObjectArrayElement(e Env, jarr ObjectArray, index Size) (Object, error) {
+	jobj := C._jni_GetObjectArrayElement(e.env, C.jobjectArray(jarr), C.jsize(index))
+	return Object(jobj), exception(e)
+}
+
+func SetObjectArrayElement(e Env, jarr ObjectArray, index Size, value Object) error {
+	C._jni_SetObjectArrayElement(
+		e.env,
+		C.jobjectArray(jarr),
+		C.jsize(index),
+		C.jobject(value))
+	return exception(e)
+}
+
 // ClassLoader returns a reference to the Java ClassLoader associated
 // with obj.
 func ClassLoaderFor(e Env, obj Object) Object {

jni_test.go

@@ -805,6 +805,42 @@ func TestByteArray(t *testing.T) {
 	})
 }
 
+func TestObjectArray(t *testing.T) {
+	Do(vm, func(env Env) error {
+		cls := FindClass(env, "java/lang/Object")
+		if cls == 0 {
+			t.Errorf("Class is nil")
+		}
+
+		strings := []string{
+			"item1",
+			"item2",
+		}
+
+		arr := NewObjectArray(env, Size(len(strings)), cls, 0)
+		for i, s := range strings {
+			jstring := JavaString(env, s)
+			err := SetObjectArrayElement(env, arr, Size(i), Object(jstring))
+			if err != nil {
+				t.Errorf("SetObjectArrayElement at index %d raised exception", i)
+			}
+		}
+
+		for i, s := range strings {
+			r, err := GetObjectArrayElement(env, arr, Size(i))
+			if err != nil {
+				t.Errorf("GetObjectArrayElement at index %d raised exception", i)
+			}
+
+			retrieved := GoString(env, String(r))
+			if s != retrieved {
+				t.Errorf("Expected item %d to be '%s' but instead was '%s'", i, s, retrieved)
+			}
+		}
+		return nil
+	})
+}
+
 func TestClassLoaderFor(t *testing.T) {
 	defer func() {
 		if r := recover(); r == nil {