Make Module support Initializable

It might be easier for the delegate class inside the module to implement
this interface than to specify the initializer inside the Plugin
annotation, especially because annotation could not be partially
overridden. Now the Initializable interface has higher priority than the
initializer annotation, and at most one of them will be called when a
module is initialized.

Closes #249.

Signed-off-by: Curtis Rueden <ctrueden@wisc.edu>

Author: lnyng

src/main/java/org/scijava/module/AbstractModule.java

@@ -35,6 +35,8 @@
 import java.util.HashSet;
 import java.util.Map;
 
+import org.scijava.Initializable;
+
 /**
  * Abstract superclass of {@link Module} implementations.
  * <p>
@@ -76,11 +78,16 @@ public void cancel() {
 	public void initialize() throws MethodCallException {
 		// execute global module initializer
 		final Object delegateObject = getDelegateObject();
-		if (initializerRef == null) {
-			final String initializer = getInfo().getInitializer();
-			initializerRef = new MethodRef(delegateObject.getClass(), initializer);
+		if (delegateObject instanceof Initializable) {
+			((Initializable) delegateObject).initialize();
+		}
+		else {
+			if (initializerRef == null) {
+				final String initializer = getInfo().getInitializer();
+				initializerRef = new MethodRef(delegateObject.getClass(), initializer);
+			}
+			initializerRef.execute(delegateObject);
 		}
-		initializerRef.execute(delegateObject);
 
 		// execute individual module item initializers
 		for (final ModuleItem<?> item : getInfo().inputs()) {