From fa98df639ead80e1d374a134ceb289fa1189114e Mon Sep 17 00:00:00 2001
From: Jean-Daniel Cryans <jdcryans@apache.org>
Date: Thu, 22 Mar 2012 18:13:12 +0000
Subject: [PATCH]    HBASE-5586  [replication] NPE in ReplicationSource when
 creating a stream                to an inexistent cluster

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1303945 13f79535-47bb-0310-9956-ffa450edef68
---
 .../replication/ReplicationZookeeper.java     |   6 +-
 .../replication/TestReplicationZookeeper.java | 118 ++++++++++++++++++
 2 files changed, 121 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/org/apache/hadoop/hbase/replication/TestReplicationZookeeper.java

diff --git a/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java b/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java
index 5ee2649d526..e1a7398119e 100644
--- a/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java
+++ b/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java
@@ -218,11 +218,11 @@ public class ReplicationZookeeper implements Closeable{
    */
   public List<ServerName> getSlavesAddresses(String peerClusterId) {
     if (this.peerClusters.size() == 0) {
-      return new ArrayList<ServerName>(0);
+      return Collections.emptyList();
     }
     ReplicationPeer peer = this.peerClusters.get(peerClusterId);
     if (peer == null) {
-      return new ArrayList<ServerName>(0);
+      return Collections.emptyList();
     }
     
     List<ServerName> addresses;
@@ -281,7 +281,7 @@ public class ReplicationZookeeper implements Closeable{
   throws KeeperException {
     List<String> children = ZKUtil.listChildrenNoWatch(zkw, znode);
     if(children == null) {
-      return null;
+      return Collections.emptyList();
     }
     List<ServerName> addresses = new ArrayList<ServerName>(children.size());
     for (String child : children) {
diff --git a/src/test/java/org/apache/hadoop/hbase/replication/TestReplicationZookeeper.java b/src/test/java/org/apache/hadoop/hbase/replication/TestReplicationZookeeper.java
new file mode 100644
index 00000000000..553b5cd7d27
--- /dev/null
+++ b/src/test/java/org/apache/hadoop/hbase/replication/TestReplicationZookeeper.java
@@ -0,0 +1,118 @@
+/**
+ * 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.hadoop.hbase.replication;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.MediumTests;
+import org.apache.hadoop.hbase.Server;
+import org.apache.hadoop.hbase.ServerName;
+import org.apache.hadoop.hbase.catalog.CatalogTracker;
+import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
+import org.apache.zookeeper.KeeperException;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+import static org.junit.Assert.assertEquals;
+
+@Category(MediumTests.class)
+public class TestReplicationZookeeper {
+
+  private static Configuration conf;
+
+  private static HBaseTestingUtility utility;
+
+  private static ZooKeeperWatcher zkw;
+
+  private static ReplicationZookeeper repZk;
+
+  private static String slaveClusterKey;
+
+  @BeforeClass
+  public static void setUpBeforeClass() throws Exception {
+    utility = new HBaseTestingUtility();
+    utility.startMiniZKCluster();
+    conf = utility.getConfiguration();
+    zkw = HBaseTestingUtility.getZooKeeperWatcher(utility);
+    DummyServer server = new DummyServer();
+    repZk = new ReplicationZookeeper(server, new AtomicBoolean());
+    slaveClusterKey = conf.get(HConstants.ZOOKEEPER_QUORUM) + ":" +
+      conf.get("hbase.zookeeper.property.clientPort") + ":/1";
+  }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    utility.shutdownMiniZKCluster();
+  }
+
+  @Test
+  public void testGetAddressesMissingSlave()
+    throws IOException, KeeperException {
+    repZk.addPeer("1", slaveClusterKey);
+    // HBASE-5586 used to get an NPE
+    assertEquals(0, repZk.getSlavesAddresses("1").size());
+  }
+
+  static class DummyServer implements Server {
+
+    @Override
+    public Configuration getConfiguration() {
+      return conf;
+    }
+
+    @Override
+    public ZooKeeperWatcher getZooKeeper() {
+      return zkw;
+    }
+
+    @Override
+    public CatalogTracker getCatalogTracker() {
+      return null;
+    }
+
+    @Override
+    public ServerName getServerName() {
+      return new ServerName("hostname.example.org", 1234, -1L);
+    }
+
+    @Override
+    public void abort(String why, Throwable e) {
+    }
+
+    @Override
+    public boolean isAborted() {
+      return false;
+    }
+
+    @Override
+    public void stop(String why) {
+    }
+
+    @Override
+    public boolean isStopped() {
+      return false;
+    }
+  }
+}