Merge pull request #483 from Thrameos/convert_string2

Enable option to support legacy conversion of strings with polymorphic return.

.gitattributes

@@ -5,6 +5,7 @@
 *.cpp text eol=lf
 *.c text eol=lf
 *.h text eol=lf
+*.java text eol=lf
 
 *.xml text eol=lf
 *.md text

.travis.yml

@@ -47,6 +47,14 @@ matrix:
       dist: xenial
       language: python
 
+    # TODO: remove in 0.8
+    - name: "Python 2.7 on Xenial Linux"
+      python: 2.7
+      dist: xenial
+      language: python
+      env:
+        - JPYPE_STR_CONVERSION=False
+
     - name: "Python 3.7 on Xenial Linux (w/o NUMPY)"
       python: 3.7
       dist: xenial
@@ -64,6 +72,16 @@ matrix:
         - PYTHON=python3
         - PIP=pip3
 
+    # TODO: remove in 0.8
+    - name: "Python 3.7 on Xenial Linux"
+      python: 3.7
+      dist: xenial
+      language: python
+      env:
+        - PYTHON=python3
+        - PIP=pip3
+        - JPYPE_STR_CONVERSION=False
+
     ## This pattern is good, but something is broken in openJDK 12
     ## Deal with in another pull
     - name: "Python 2.7 on macOS"
@@ -101,3 +119,4 @@ install:
 script:
   - $PYTHON -c "import jpype"
   - $PYTHON -m pytest -v test/jpypetest
+

jpype/_core.py

@@ -113,7 +113,7 @@ def _handleClassPath(clsList):
 def startJVM(*args, **kwargs):
     """
     Starts a Java Virtual Machine.  Without options it will start
-    the JVM with the default classpath and jvmpath.  
+    the JVM with the default classpath and jvmpath.
 
     The default classpath is determined by ``jpype.getClassPath()``.
     The default jvmpath is determined by ``jpype.getDefaultJVMPath()``.
@@ -124,17 +124,29 @@ def startJVM(*args, **kwargs):
 
     Keyword Arguments:
       jvmpath (str):  Path to the jvm library file,
-        Typically one of (``libjvm.so``, ``jvm.dll``, ...) 
+        Typically one of (``libjvm.so``, ``jvm.dll``, ...)
         Using None will apply the default jvmpath.
       classpath (str,[str]): Set the classpath for the jvm.
         This will override any classpath supplied in the arguments
         list. A value of None will give no classpath to JVM.
       ignoreUnrecognized (bool): Option to JVM to ignore
         invalid JVM arguments. Default is False.
+      convertStrings (bool): Option to JPype to force Java strings to
+        cast to Python strings. This option is to support legacy code
+        for which conversion of Python strings was the default. This
+        will globally change the behavior of all calls using
+        strings, and a value of True is NOT recommended for newly 
+        developed code.
+
+        The default value for this option during 0.7 series is 
+        True.  The option will be False starting in 0.8. A
+        warning will be issued if this option is not specified
+        during the transition period.
+
 
     Raises:
       OSError: if the JVM cannot be started or is already running.
-      TypeError: if an invalid keyword argument is supplied 
+      TypeError: if an invalid keyword argument is supplied
         or a keyword argument conflicts with the arguments.
 
      """
@@ -185,11 +197,26 @@ def startJVM(*args, **kwargs):
 
     ignoreUnrecognized = kwargs.pop('ignoreUnrecognized', False)
 
+    if not "convertStrings" in kwargs:
+        import warnings
+        warnings.warn("""
+-------------------------------------------------------------------------------
+Deprecated: convertStrings was not specified when starting the JVM. The default
+behavior in JPype will be False starting in JPype 0.8. The recommended setting
+for new code is convertStrings=False.  The legacy value of True was assumed for
+this session. If you are a user of an application that reported this warning,
+please file a ticket with the developer.
+-------------------------------------------------------------------------------
+""")
+
+    convertStrings = kwargs.pop('convertStrings', True)
+
+
     if kwargs:
         raise TypeError("startJVM() got an unexpected keyword argument '%s'"
                         % (','.join([str(i) for i in kwargs])))
 
-    _jpype.startup(jvmpath, tuple(args), ignoreUnrecognized)
+    _jpype.startup(jvmpath, tuple(args), ignoreUnrecognized, convertStrings)
     _initialize()
 
 
@@ -201,8 +228,8 @@ def attachToJVM(jvm):
 def shutdownJVM():
     """ Shuts down the JVM.
 
-    This method shuts down the JVM and thus disables access to existing 
-    Java objects. Due to limitations in the JPype, it is not possible to 
+    This method shuts down the JVM and thus disables access to existing
+    Java objects. Due to limitations in the JPype, it is not possible to
     restart the JVM after being terminated.
     """
     _jpype.shutdown()
@@ -211,10 +238,10 @@ def shutdownJVM():
 def isThreadAttachedToJVM():
     """ Checks if a thread is attached to the JVM.
 
-    Python automatically attaches threads when a Java method is called. 
-    This creates a resource in Java for the Python thread. This method 
-    can be used to check if a Python thread is currently attached so that 
-    it can be disconnected prior to thread termination to prevent leaks.  
+    Python automatically attaches threads when a Java method is called.
+    This creates a resource in Java for the Python thread. This method
+    can be used to check if a Python thread is currently attached so that
+    it can be disconnected prior to thread termination to prevent leaks.
 
     Returns:
       True if the thread is attached to the JVM, False if the thread is
@@ -226,8 +253,8 @@ def isThreadAttachedToJVM():
 def attachThreadToJVM():
     """ Attaches a thread to the JVM.
 
-    The function manually connects a thread to the JVM to allow access to 
-    Java objects and methods. JPype automaticatlly attaches when a Java 
+    The function manually connects a thread to the JVM to allow access to
+    Java objects and methods. JPype automaticatlly attaches when a Java
     resource is used, so a call to this is usually not needed.
 
     Raises:
@@ -241,7 +268,7 @@ def detachThreadFromJVM():
 
     This function detaches the thread and frees the associated resource in
     the JVM. For codes making heavy use of threading this should be used
-    to prevent resource leaks. The thread can be reattached, so there 
+    to prevent resource leaks. The thread can be reattached, so there
     is no harm in detaching early or more than once. This method cannot fail
     and there is no harm in calling it when the JVM is not running.
     """
@@ -252,7 +279,7 @@ def synchronized(obj):
     """ Creates a resource lock for a Java object.
 
     Produces a monitor object. During the lifespan of the monitor the Java
-    will not be able to acquire a thread lock on the object. This will 
+    will not be able to acquire a thread lock on the object. This will
     prevent multiple threads from modifying a shared resource.
 
     This should always be used as part of a Python ``with`` startment.
@@ -319,8 +346,8 @@ def get_default_jvm_path(*args, **kwargs):
 def getJVMVersion():
     """ Get the JVM version if the JVM is started.
 
-    This function can be used to determine the version of the JVM. It is 
-    useful to help determine why a Jar has failed to load.  
+    This function can be used to determine the version of the JVM. It is
+    useful to help determine why a Jar has failed to load.
 
     Returns:
       A typle with the (major, minor, revison) of the JVM if running.

native/common/include/jp_env.h

@@ -44,7 +44,7 @@ namespace JPEnv
 	 * Load the JVM
 	 * TODO : add the non-string parameters, for possible callbacks
 	 */
-	void loadJVM(const string& vmPath, char ignoreUnrecognized, const StringVector& args);
+	void loadJVM(const string& vmPath, const StringVector& args, bool ignoreUnrecognized, bool convertStrings);
 
 	void attachJVM(const string& vmPath);
 
@@ -62,6 +62,8 @@ namespace JPEnv
 
 	void CreateJavaVM(void* arg);
 	void GetCreatedJavaVM();
+
+        bool getConvertStrings();
 }
 
 #endif // _JPENV_H_

native/common/jp_env.cpp

@@ -26,6 +26,7 @@
 namespace
 { // impl details
 	JavaVM* s_JavaVM = NULL;
+	bool s_ConvertStrings = false;
 
 	jint(JNICALL *CreateJVM_Method)(JavaVM **pvm, void **penv, void *args);
 	jint(JNICALL *GetCreatedJVMs_Method)(JavaVM **pvm, jsize size, jsize* nVms);
@@ -137,9 +138,10 @@ void loadEntryPoints(const string& path)
 	GetCreatedJVMs_Method = (jint(JNICALL *)(JavaVM **, jsize, jsize*))GetAdapter()->getSymbol("JNI_GetCreatedJavaVMs");
 }
 
-void JPEnv::loadJVM(const string& vmPath, char ignoreUnrecognized, const StringVector& args)
+void JPEnv::loadJVM(const string& vmPath, const StringVector& args, bool ignoreUnrecognized, bool convertStrings)
 {
 	JP_TRACE_IN("JPEnv::loadJVM");
+        s_ConvertStrings = convertStrings;
 
 	// Get the entry points in the shared library
 	loadEntryPoints(vmPath);
@@ -177,6 +179,11 @@ void JPEnv::loadJVM(const string& vmPath, char ignoreUnrecognized, const StringV
 	JP_TRACE_OUT;
 }
 
+bool JPEnv::getConvertStrings()
+{
+  return s_ConvertStrings;
+}
+
 void JPEnv::shutdown()
 {
 	JP_TRACE_IN("JPEnv::shutdown");

native/common/jp_stringclass.cpp

@@ -12,7 +12,7 @@
    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.
-   
+
  *****************************************************************************/
 #include <jpype.h>
 
@@ -33,6 +33,23 @@ JPPyObject JPStringClass::convertToPythonObject(jvalue val)
 		return JPPyObject::getNone();
 	}
 
+	if (JPEnv::getConvertStrings())
+	{
+		bool unicode = false;
+		string str = JPJni::toStringUTF8((jstring) (val.l));
+#if PY_MAJOR_VERSION < 3
+		for (int i = 0; i < str.size(); ++i)
+		{
+			if (str[i]&0x80)
+			{
+				unicode = true;
+				break;
+			}
+		}
+#endif
+		return JPPyString::fromStringUTF8(str, unicode);
+	}
+
 	return JPPythonEnv::newJavaObject(JPValue(this, val));
 	JP_TRACE_OUT;
 }
@@ -78,7 +95,7 @@ jvalue JPStringClass::convertToJava(PyObject* obj)
 		return res;
 	}
 
-	// java.lang.string is already a global object 
+	// java.lang.string is already a global object
 	JPValue* value = JPPythonEnv::getJavaValue(obj);
 	if (value != NULL)
 	{

native/python/pyjp_module.cpp

@@ -12,7 +12,7 @@
    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.
-   
+
  *****************************************************************************/
 
 #include <pyjp.h>
@@ -62,7 +62,7 @@ PyMODINIT_FUNC PyInit__jpype()
 PyMODINIT_FUNC init_jpype()
 #endif
 {
-	// This is required for python versions prior to 3.7.  
+	// This is required for python versions prior to 3.7.
 	// It is called by the python initialization starting from 3.7,
 	// but is safe to call afterwards.
 	PyEval_InitThreads();
@@ -117,8 +117,10 @@ PyObject* PyJPModule::startup(PyObject* obj, PyObject* args)
 		PyObject* vmOpt;
 		PyObject* vmPath;
 		char ignoreUnrecognized = true;
+		char convertStrings = false;
 
-		if (!PyArg_ParseTuple(args, "OO!b|", &vmPath, &PyTuple_Type, &vmOpt, &ignoreUnrecognized))
+		if (!PyArg_ParseTuple(args, "OO!bb", &vmPath, &PyTuple_Type, &vmOpt,
+                      &ignoreUnrecognized, &convertStrings))
 		{
 			return NULL;
 		}
@@ -151,7 +153,7 @@ PyObject* PyJPModule::startup(PyObject* obj, PyObject* args)
 			}
 		}
 
-		JPEnv::loadJVM(cVmPath, ignoreUnrecognized, args);
+		JPEnv::loadJVM(cVmPath, args, ignoreUnrecognized, convertStrings);
 		Py_RETURN_NONE;
 	}
 	PY_STANDARD_CATCH;
@@ -324,7 +326,7 @@ PyObject* PyJPModule::convertToDirectByteBuffer(PyObject* self, PyObject* args)
 			// Bind lifespan of the python to the java object.
 			JPReferenceQueue::registerRef(ref, src);
 
-			// Convert to python object 
+			// Convert to python object
 
 			jvalue v;
 			v.l = ref;

setup.py

@@ -40,7 +40,7 @@
     package_dir={
         'jpype': 'jpype',
     },
-    setup_requires=['setuptools_scm'],
+    #setup_requires=['setuptools_scm'],
     tests_require=['pytest', 'mock', 'unittest2'],
     extras_require={'numpy': ['numpy>=1.6']},
     cmdclass={

test/harness/jpype/array/TestArray.java

@@ -27,7 +27,7 @@ public TestArray()
 
     public Object[] getSubClassArray()
     {
-      return new String[] { "aaa", "bbb" };
+      return new Integer[] { 1, 2 };
     }
 
     public Object getArrayAsObject()
@@ -45,4 +45,4 @@ public byte[] getByteArray()
     	String s = "avcd";
     	return s.getBytes();
     }
-}
+}

test/harness/jpype/str/StringFunction.java

@@ -0,0 +1,6 @@
+package jpype.str;
+
+public interface StringFunction
+{
+	public String call(String s);
+}

test/harness/jpype/str/Test.java

@@ -0,0 +1,28 @@
+package jpype.str;
+
+public class Test
+{
+
+	public static String staticField = "staticField";
+	public String memberField = "memberField";
+
+	public static String staticCall()
+	{
+		return "staticCall";
+	}
+
+	public String memberCall()
+	{
+		return "memberCall";
+	}
+
+	public static final String array[] =
+	{"apples","banana","cherries","dates","elderberry"};
+
+	public static String callProxy(StringFunction f, String s)
+	{
+		return f.call(s);
+	}
+}
+
+