Report non-optional services' failing to initialize

dscho · ctrueden · commit 25beaf628a98 · 2013-07-22T13:33:13.000-05:00
This hopefully addresses the issue that some services should not clutter
the log when failing to initialize (such as SCIFIO's LuraWaveService),
but other services should not fail silently, such as ImageJ2's
LUTService or LegacyService.

From now on, we can mark the former category of services with the
Optional interface and still have helpful information from the log in
case essential services were not initialized (and therefore not added
to the set of available services).

Signed-off-by: Johannes Schindelin &lt;johannes.schindelin@gmx.de&gt;
diff --git a/src/main/java/org/scijava/service/ServiceHelper.java b/src/main/java/org/scijava/service/ServiceHelper.java
@@ -44,6 +44,7 @@
 
 import org.scijava.AbstractContextual;
 import org.scijava.Context;
+import org.scijava.Optional;
 import org.scijava.event.EventService;
 import org.scijava.log.LogService;
 import org.scijava.log.StderrLogService;
@@ -180,8 +181,15 @@ public <S extends Service> S createExactService(final Class<S> c) {
 		}
 		catch (final Throwable t) {
 			if (log.isDebug()) {
+				// when in debug mode, always give full stack trace of invalid services
 				log.debug("Invalid service: " + c.getName(), t);
-			} else {
+			}
+			else if (!Optional.class.isAssignableFrom(c)) {
+				// for required (i.e., non-optional) services, we also dump the stack
+				log.warn("Invalid service: " + c.getName(), t);
+			}
+			else {
+				// we emit only a short warning for failing optional services
 				log.warn("Invalid service: " + c.getName());
 			}
 		}
