HBASE-23305: Remove dead code in AsyncRegistry

This is a prep change for master based async registry impl.
Removes a bunch of dead code and fixes some checkstyle nits.

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/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 org.apache.hbase.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 {
@@ -210,11 +207,6 @@ 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;
@@ -237,12 +229,6 @@ 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-server/src/test/java/org/apache/hadoop/hbase/client/DummyAsyncRegistry.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
@@ -39,21 +39,11 @@ public CompletableFuture<String> getClusterId() {
     return null;
   }
 
-  @Override
-  public CompletableFuture<Integer> getCurrentNrHRS() {
-    return null;
-  }
-
   @Override
   public CompletableFuture<ServerName> getMasterAddress() {
     return null;
   }
 
-  @Override
-  public CompletableFuture<Integer> getMasterInfoPort() {
-    return null;
-  }
-
   @Override
   public void close() {
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestZKAsyncRegistry.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
@@ -25,7 +25,6 @@
 import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
-
 import java.io.IOException;
 import java.util.concurrent.ExecutionException;
 import java.util.stream.IntStream;
@@ -84,11 +83,8 @@ public void test() throws InterruptedException, ExecutionException, IOException
     String expectedClusterId = TEST_UTIL.getHBaseCluster().getMaster().getClusterId();
     assertEquals("Expected " + expectedClusterId + ", found=" + clusterId, expectedClusterId,
       clusterId);
-    assertEquals(TEST_UTIL.getHBaseCluster().getClusterMetrics().getLiveServerMetrics().size(),
-      REGISTRY.getCurrentNrHRS().get().intValue());
     assertEquals(TEST_UTIL.getHBaseCluster().getMaster().getServerName(),
       REGISTRY.getMasterAddress().get());
-    assertEquals(-1, REGISTRY.getMasterInfoPort().get().intValue());
     RegionReplicaTestHelper
       .waitUntilAllMetaReplicasHavingRegionLocation(TEST_UTIL.getConfiguration(), REGISTRY, 3);
     RegionLocations locs = REGISTRY.getMetaRegionLocation().get();