MBeanModule.newExporter() to ease exporting inside other modules.

Returns ExportBuilder() that wraps a Multibinder<Mapping>.

This is to avoid problems where you install() a 
MBeanModule inside another module that doesn't bind
MBeanServer; MBeanModule implicitly requires a bound
MBeanServer.

.gitignore

@@ -1,3 +1,6 @@
 /target
 /*.iws
 /test-output
+.classpath
+.project
+.settings

README.md

@@ -28,14 +28,26 @@
 # Guice support
 
     Injector injector = Guice.createInjector(
-                new MBeanModule() {
-                    @Override
-                    protected void configureMBeans()
-                    {
-                        export(ManagedObject.class).as("test:name=X");
-                        export(ManagedObject.class).annotatedWith(SomeAnnotation.class).as("test:name=Y");
-                    }
-                }, ...);
+        new MBeanModule() {
+            @Override
+            protected void configureMBeans()
+            {
+                export(ManagedObject.class).as("test:name=X");
+                export(ManagedObject.class).annotatedWith(SomeAnnotation.class).as("test:name=Y");
+            }
+        }, new AbstractModule() {
+	    @Override
+   	    protected void configure() {	
+                /* 
+		 * You don't want to install() a MBeanModule in another module
+		 * because you'll get binding errors; MBeanModule requires you 
+		 * to bind a MBeanServer outside of it. Use the ExportBuilder
+		 * in this case.
+		 */
+                ExportBuilder builder = MBeanModule.newExporter();
+		builder.export(AnotherManagedObject.class).as("test:name="X");
+	    }
+        }, ...);
 
 # License
 

src/main/java/org/weakref/jmx/guice/ExportBuilder.java

@@ -0,0 +1,15 @@
+package org.weakref.jmx.guice;
+
+import com.google.inject.multibindings.Multibinder;
+
+public class ExportBuilder {
+	private final Multibinder<Mapping> binder; 
+
+	ExportBuilder(Multibinder<Mapping> binder) {
+		this.binder = binder;
+	}
+
+	public AnnotatedExportBuilder export(Class<?> clazz) {
+		return new AnnotatedExportBuilder(binder, clazz);
+	}
+}

src/main/java/org/weakref/jmx/guice/MBeanModule.java

@@ -15,18 +15,20 @@
  */
 package org.weakref.jmx.guice;
 
+import static com.google.inject.multibindings.Multibinder.newSetBinder;
+
 import com.google.inject.AbstractModule;
-import com.google.inject.multibindings.Multibinder;
+import com.google.inject.Binder;
 
 public abstract class MBeanModule
         extends AbstractModule
 {
-    private Multibinder<Mapping> binder;
+    private ExportBuilder builder;
 
     @Override
     protected final void configure()
     {
-        binder = Multibinder.newSetBinder(binder(), Mapping.class);
+        builder = newExporter(binder());
 
         install(new InternalMBeanModule());
         configureMBeans();
@@ -36,7 +38,12 @@ protected final void configure()
 
     protected AnnotatedExportBuilder export(Class<?> clazz)
     {
-        return new AnnotatedExportBuilder(binder, clazz);
+        return builder.export(clazz);
+    }
+
+    public static ExportBuilder newExporter(Binder binder) 
+    {
+    	return new ExportBuilder(newSetBinder(binder, Mapping.class));
     }
 
 }

src/test/java/org/weakref/jmx/guice/TestMBeanModule.java

@@ -20,7 +20,10 @@
 import com.google.inject.AbstractModule;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
+import com.google.inject.Key;
 import com.google.inject.Stage;
+import com.google.inject.binder.LinkedBindingBuilder;
+import com.google.inject.multibindings.Multibinder;
 import com.google.inject.name.Names;
 import org.weakref.jmx.SimpleObject;
 import org.weakref.jmx.Util;
@@ -206,4 +209,42 @@ protected void configureMBeans()
         server.unregisterMBean(objectName1);
         server.unregisterMBean(objectName2);
     }
+
+    @Test
+    public void testExportBuilder() 
+    	throws IntrospectionException, InstanceNotFoundException, ReflectionException, MBeanRegistrationException
+    {
+    	final ObjectName objectName1 = Util.getUniqueObjectName();
+        final ObjectName objectName2 = Util.getUniqueObjectName();
+
+        Injector injector = Guice.createInjector(PRODUCTION, new MBeanModule() {
+			@Override
+			protected void configureMBeans() {
+
+			}}, new AbstractModule()
+        {
+			@Override
+			protected void configure() {
+                bind(MBeanServer.class).toInstance(ManagementFactory.getPlatformMBeanServer());
+                bind(SimpleObject.class).annotatedWith(Names.named("1")).toInstance(new SimpleObject());
+                bind(SimpleObject.class).annotatedWith(Names.named("2")).toInstance(new SimpleObject());
+
+                ExportBuilder exporter = MBeanModule.newExporter(binder());
+				exporter.export(SimpleObject.class)
+					.annotatedWith(Names.named("1"))
+					.as(objectName1.getCanonicalName());
+				exporter.export(SimpleObject.class)
+					.annotatedWith(Names.named("2"))
+					.as(objectName2.getCanonicalName());
+			}
+        });
+
+        MBeanServer server = injector.getInstance(MBeanServer.class);
+
+        Assert.assertNotNull(server.getMBeanInfo(objectName1));
+        Assert.assertNotNull(server.getMBeanInfo(objectName2));
+
+        server.unregisterMBean(objectName1);
+        server.unregisterMBean(objectName2);
+    }
 }