merge master -Dorg -Ssuccess-only: PR 290 (Assert connection decorato…

…r, see ome#289)

src/omero/gateway/__init__.py

@@ -26,7 +26,7 @@
 from past.utils import old_div
 from builtins import object
 import os
-
+from functools import wraps
 import warnings
 from collections import defaultdict
 
@@ -1505,6 +1505,23 @@ def values(self):
         return ()
 
 
+def assertConnected(func):
+    """decorator that raises an exception if  the decorated function is used when the gateway
+    is not connected.
+
+    Assumes the first argument is a BlitzGateway instance, or the function
+    is a BlitzGateway method
+
+    """
+    @wraps(func)
+    def wrapped(conn, *args, **kwargs):
+        if not conn._connected:
+            raise Ice.ConnectionLostException("Trying to call %s while not connected" % func.__name__)
+
+        return func(conn, *args, **kwargs)
+    return wrapped
+
+
 class _BlitzGateway (object):
     """
     Connection wrapper. Handles connecting and keeping the session alive,
@@ -2308,12 +2325,11 @@ def isConnected(self):
 
         :return:    Boolean
         """
-
         return self._connected
 
     ########################
     # # Connection Stuff # #
-
+    @assertConnected
     def getEventContext(self):
         """
         Returns omero_System_ice.EventContext.

test/unit/test_gateway.py

@@ -30,7 +30,7 @@
 import sys
 
 from omero.gateway import BlitzGateway, ImageWrapper, \
-    WellWrapper, LogicalChannelWrapper, OriginalFileWrapper
+    WellWrapper, LogicalChannelWrapper, OriginalFileWrapper, assertConnected
 from omero.model import ImageI, PixelsI, ExperimenterI, EventI, \
     ProjectI, TagAnnotationI, FileAnnotationI, OriginalFileI, \
     MapAnnotationI, NamedValue, PlateI, WellI, \
@@ -40,6 +40,31 @@
 from omero.rtypes import rstring, rtime, rlong, rint, rdouble
 
 
+def test_assertConnected():
+
+    class MockGateway:
+        _connected = False
+
+        def connect(self):
+            self._connected = True
+            return True
+
+        def isConnected(self):
+            return self._connected
+
+        @assertConnected
+        def foo(self):
+            return 1
+
+    conn = MockGateway()
+    assert not conn.isConnected()
+    with pytest.raises(Ice.ConnectionLostException):
+        conn.foo()
+
+    assert conn.connect()
+    assert conn.foo()
+
+
 class MockQueryService(object):
 
     def __init__(self, obj_to_be_returned):