HBASE-23575 Remove dead code in AsyncRegistry (apache#940)

Removes a bunch of dead code and fixes some checkstyle nits.

(cherry picked from commit efa4fe9)
Signed-off-by: Jan Hentschel <janh@apache.org>
Signed-off-by: Xu Cang <xucang@apache.org>
Signed-off-by: Sean Busbey <busbey@apache.org>
Signed-off-by: Viraj Jasani <virajjasani007@gmail.com>

Author: bharathv

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegistry.java

@@ -1,4 +1,4 @@
-/**
+/*
  * 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
@@ -19,15 +19,12 @@
 
 import java.io.Closeable;
 import java.util.concurrent.CompletableFuture;
-
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
  * Implementations hold cluster information such as this cluster's id, location of hbase:meta, etc..
- * All stuffs that may be related to zookeeper at client side are placed here.
- * <p>
  * Internal use only.
  */
 @InterfaceAudience.Private
@@ -45,21 +42,11 @@ interface AsyncRegistry extends Closeable {
    */
   CompletableFuture<String> getClusterId();
 
-  /**
-   * Get the number of 'running' regionservers.
-   */
-  CompletableFuture<Integer> getCurrentNrHRS();
-
   /**
    * Get the address of HMaster.
    */
   CompletableFuture<ServerName> getMasterAddress();
 
-  /**
-   * Get the info port of HMaster.
-   */
-  CompletableFuture<Integer> getMasterInfoPort();
-
   /**
    * Closes this instance and releases any system resources associated with it
    */

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClusterConnection.java

@@ -323,10 +323,4 @@ HRegionLocation getRegionLocation(TableName tableName, byte[] row, boolean reloa
    *         supports cell blocks.
    */
   boolean hasCellBlockSupport();
-
-  /**
-   * @return the number of region servers that are currently running
-   * @throws IOException if a remote or network exception occurs
-   */
-  int getCurrentNrHRS() throws IOException;
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java

@@ -2077,11 +2077,6 @@ public boolean isAborted(){
     return this.aborted;
   }
 
-  @Override
-  public int getCurrentNrHRS() throws IOException {
-    return get(this.registry.getCurrentNrHRS());
-  }
-
   @Override
   public void close() {
     if (this.closed) {

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZKAsyncRegistry.java

@@ -1,4 +1,4 @@
-/**
+/*
  * 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
@@ -24,7 +24,6 @@
 import static org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil.lengthOfPBMagic;
 import static org.apache.hadoop.hbase.util.FutureUtils.addListener;
 import static org.apache.hadoop.hbase.zookeeper.ZKMetadata.removeMetaData;
-
 import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
@@ -43,14 +42,12 @@
 import org.apache.yetus.audience.InterfaceAudience;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import com.xiaomi.infra.thirdparty.com.google.common.annotations.VisibleForTesting;
-
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ZooKeeperProtos;
 
 /**
- * Fetch the registry data from zookeeper.
+ * Zookeeper based registry implementation.
  */
 @InterfaceAudience.Private
 class ZKAsyncRegistry implements AsyncRegistry {
@@ -212,11 +209,6 @@ public CompletableFuture<RegionLocations> getMetaRegionLocation() {
     return future;
   }
 
-  @Override
-  public CompletableFuture<Integer> getCurrentNrHRS() {
-    return zk.exists(znodePaths.rsZNode).thenApply(s -> s != null ? s.getNumChildren() : 0);
-  }
-
   private static ZooKeeperProtos.Master getMasterProto(byte[] data) throws IOException {
     if (data == null || data.length == 0) {
       return null;
@@ -239,12 +231,6 @@ public CompletableFuture<ServerName> getMasterAddress() {
         });
   }
 
-  @Override
-  public CompletableFuture<Integer> getMasterInfoPort() {
-    return getAndConvert(znodePaths.masterAddressZNode, ZKAsyncRegistry::getMasterProto)
-        .thenApply(proto -> proto != null ? proto.getInfoPort() : 0);
-  }
-
   @Override
   public void close() {
     zk.close();

hbase-client/src/test/java/org/apache/hadoop/hbase/client/DoNothingAsyncRegistry.java

@@ -1,4 +1,4 @@
-/**
+/*
  * 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
@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.client;
 
 import java.util.concurrent.CompletableFuture;
-
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
@@ -43,21 +42,11 @@ public CompletableFuture<String> getClusterId() {
     return CompletableFuture.completedFuture(null);
   }
 
-  @Override
-  public CompletableFuture<Integer> getCurrentNrHRS() {
-    return CompletableFuture.completedFuture(0);
-  }
-
   @Override
   public CompletableFuture<ServerName> getMasterAddress() {
     return CompletableFuture.completedFuture(null);
   }
 
-  @Override
-  public CompletableFuture<Integer> getMasterInfoPort() {
-    return CompletableFuture.completedFuture(0);
-  }
-
   @Override
   public void close() {
   }

hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncProcess.java

@@ -472,11 +472,6 @@ public TestRegistry(Configuration conf) {
       public CompletableFuture<String> getClusterId() {
         return CompletableFuture.completedFuture("testClusterId");
       }
-
-      @Override
-      public CompletableFuture<Integer> getCurrentNrHRS() {
-        return CompletableFuture.completedFuture(1);
-      }
     }
 
     final AtomicInteger nbThreads = new AtomicInteger(0);

hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestClientNoCluster.java

@@ -144,11 +144,6 @@ public CompletableFuture<RegionLocations> getMetaRegionLocation() {
     public CompletableFuture<String> getClusterId() {
       return CompletableFuture.completedFuture(HConstants.CLUSTER_ID_DEFAULT);
     }
-
-    @Override
-    public CompletableFuture<Integer> getCurrentNrHRS() {
-      return CompletableFuture.completedFuture(1);
-    }
   }
 
   /**

hbase-server/src/test/java/org/apache/hadoop/hbase/MiniHBaseCluster.java

@@ -787,6 +787,13 @@ public void compact(TableName tableName, boolean major) throws IOException {
     }
   }
 
+  /**
+   * @return Number of live region servers in the cluster currently.
+   */
+  public int getNumLiveRegionServers() {
+    return this.hbaseCluster.getLiveRegionServers().size();
+  }
+
   /**
    * @return List of region server threads. Does not return the master even though it is also
    * a region server.

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java

@@ -215,7 +215,7 @@ public void testCreateTableWithRegions() throws IOException, InterruptedExceptio
       assertTrue(Bytes.equals(hri.getStartKey(), splitKeys[8]));
       assertTrue(hri.getEndKey() == null || hri.getEndKey().length == 0);
 
-      verifyRoundRobinDistribution(conn, l, expectedRegions);
+      verifyRoundRobinDistribution(l, expectedRegions);
     }
 
     // Now test using start/end with a number of regions
@@ -272,7 +272,7 @@ public void testCreateTableWithRegions() throws IOException, InterruptedExceptio
       assertTrue(Bytes.equals(hri.getStartKey(), new byte[] { 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 }));
       assertTrue(hri.getEndKey() == null || hri.getEndKey().length == 0);
 
-      verifyRoundRobinDistribution(conn, l, expectedRegions);
+      verifyRoundRobinDistribution(l, expectedRegions);
     }
 
     // Try once more with something that divides into something infinite
@@ -293,7 +293,7 @@ public void testCreateTableWithRegions() throws IOException, InterruptedExceptio
         expectedRegions, regions.size());
       System.err.println("Found " + regions.size() + " regions");
 
-      verifyRoundRobinDistribution(conn, l, expectedRegions);
+      verifyRoundRobinDistribution(l, expectedRegions);
     }
 
     // Try an invalid case where there are duplicate split keys
@@ -342,9 +342,9 @@ public void testCreateTableWithEmptyRowInTheSplitKeys() throws IOException {
     }
   }
 
-  private void verifyRoundRobinDistribution(ClusterConnection c, RegionLocator regionLocator,
-      int expectedRegions) throws IOException {
-    int numRS = c.getCurrentNrHRS();
+  private void verifyRoundRobinDistribution(RegionLocator regionLocator, int expectedRegions)
+      throws IOException {
+    int numRS = TEST_UTIL.getMiniHBaseCluster().getNumLiveRegionServers();
     List<HRegionLocation> regions = regionLocator.getAllRegionLocations();
     Map<ServerName, List<RegionInfo>> server2Regions = new HashMap<>();
     for (HRegionLocation loc : regions) {

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableAdminApi.java

@@ -22,8 +22,6 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
-
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -52,7 +50,7 @@
 /**
  * Class to test asynchronous table admin operations.
  * @see TestAsyncTableAdminApi2 This test and it used to be joined it was taking longer than our
- * ten minute timeout so they were split.
+ *     ten minute timeout so they were split.
  * @see TestAsyncTableAdminApi3 Another split out from this class so each runs under ten minutes.
  */
 @RunWith(Parameterized.class)
@@ -268,9 +266,8 @@ public void testCreateTableWithRegions() throws Exception {
     }
   }
 
-  private void verifyRoundRobinDistribution(List<HRegionLocation> regions, int expectedRegions)
-      throws IOException {
-    int numRS = ((ClusterConnection) TEST_UTIL.getConnection()).getCurrentNrHRS();
+  private void verifyRoundRobinDistribution(List<HRegionLocation> regions, int expectedRegions) {
+    int numRS = TEST_UTIL.getMiniHBaseCluster().getNumLiveRegionServers();
 
     Map<ServerName, List<RegionInfo>> server2Regions = new HashMap<>();
     regions.stream().forEach((loc) -> {