Repository: apache/incubator-fluo (java)

Issue:
Old/new observers config exception is causing ITs to fail
Multiple ITs are failing due to exception. It looks like this was caused by #817.

```
org.apache.fluo.api.exceptions.FluoException: Failed to update shared configuration in Zookeeper
Caused by: java.lang.IllegalArgumentException: Old and new observers configuration present.  There can only be one.
```

Pull request description:
Fixes #818 - Old/new observers config exception is causing ITs to fail
* Fixed bug and created unit test to verify

Patch:
diff --git a/modules/api/src/main/java/org/apache/fluo/api/config/FluoConfiguration.java b/modules/api/src/main/java/org/apache/fluo/api/config/FluoConfiguration.java
index c759dbb3..782393bc 100644
--- a/modules/api/src/main/java/org/apache/fluo/api/config/FluoConfiguration.java
+++ b/modules/api/src/main/java/org/apache/fluo/api/config/FluoConfiguration.java
@@ -306,7 +306,8 @@ public class FluoConfiguration extends SimpleConfiguration {
 
     while (iter.hasNext()) {
       String key = iter.next();
-      if (key.startsWith(FluoConfiguration.OBSERVER_PREFIX)) {
+      if (key.startsWith(FluoConfiguration.OBSERVER_PREFIX)
+          && !key.equals(FluoConfiguration.OBSERVER_PROVIDER)) {
         String value = getString(key).trim();
 
         if (value.isEmpty()) {


Test patch:
diff --git a/modules/core/src/test/java/org/apache/fluo/core/observer/ObserverStoreTest.java b/modules/core/src/test/java/org/apache/fluo/core/observer/ObserverStoreTest.java
new file mode 100644
index 00000000..586d6780
--- /dev/null
+++ b/modules/core/src/test/java/org/apache/fluo/core/observer/ObserverStoreTest.java
@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+ * agreements. See the NOTICE file distributed with this work for additional information regarding
+ * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License. You may obtain a
+ * copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, 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.
+ */
+
+package org.apache.fluo.core.observer;
+
+import org.apache.fluo.api.config.FluoConfiguration;
+import org.apache.fluo.api.config.ObserverSpecification;
+import org.apache.fluo.core.observer.v1.ObserverStoreV1;
+import org.apache.fluo.core.observer.v2.ObserverStoreV2;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ObserverStoreTest {
+
+  @Test
+  public void testNewAndOldConfig() {
+    ObserverStore ov1 = new ObserverStoreV1();
+    ObserverStore ov2 = new ObserverStoreV2();
+
+    FluoConfiguration config = new FluoConfiguration();
+    Assert.assertFalse(ov1.handles(config));
+    Assert.assertFalse(ov2.handles(config));
+
+    config = new FluoConfiguration();
+    config.setObserverProvider("TestProvider1");
+    Assert.assertFalse(ov1.handles(config));
+    Assert.assertTrue(ov2.handles(config));
+
+    config = new FluoConfiguration();
+    config.addObserver(new ObserverSpecification("TestProvider2"));
+    Assert.assertTrue(ov1.handles(config));
+    Assert.assertFalse(ov2.handles(config));
+  }
+}