HBASE-27203 Clean up error-prone findings in hbase-client

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

@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase;
 
 import java.util.Collections;
+import java.util.IdentityHashMap;
 import java.util.Map;
 import java.util.stream.Collectors;
 import org.apache.hadoop.hbase.client.RegionInfo;
@@ -28,7 +29,7 @@ public final class CacheEvictionStats {
 
   private final long evictedBlocks;
   private final long maxCacheSize;
-  private final Map<byte[], Throwable> exceptions;
+  private final IdentityHashMap<byte[], Throwable> exceptions;
 
   CacheEvictionStats(CacheEvictionStatsBuilder builder) {
     this.evictedBlocks = builder.evictedBlocks;
@@ -44,6 +45,7 @@ public long getMaxCacheSize() {
     return maxCacheSize;
   }
 
+  @SuppressWarnings("IdentityHashMapUsage")
   public Map<byte[], Throwable> getExceptions() {
     return Collections.unmodifiableMap(exceptions);
   }

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

@@ -17,15 +17,15 @@
  */
 package org.apache.hadoop.hbase;
 
-import java.util.HashMap;
-import java.util.Map;
+import java.util.IdentityHashMap;
 import org.apache.yetus.audience.InterfaceAudience;
 
 @InterfaceAudience.Private
 public final class CacheEvictionStatsBuilder {
+
   long evictedBlocks = 0;
   long maxCacheSize = 0;
-  Map<byte[], Throwable> exceptions = new HashMap<>();
+  IdentityHashMap<byte[], Throwable> exceptions = new IdentityHashMap<>();
 
   CacheEvictionStatsBuilder() {
   }
@@ -44,6 +44,7 @@ public void addException(byte[] regionName, Throwable ie) {
     exceptions.put(regionName, ie);
   }
 
+  @SuppressWarnings("IdentityHashMapUsage")
   public CacheEvictionStatsBuilder append(CacheEvictionStats stats) {
     this.evictedBlocks += stats.getEvictedBlocks();
     this.maxCacheSize += stats.getMaxCacheSize();
@@ -54,4 +55,5 @@ public CacheEvictionStatsBuilder append(CacheEvictionStats stats) {
   public CacheEvictionStats build() {
     return new CacheEvictionStats(this);
   }
+
 }

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

@@ -349,8 +349,8 @@ public static TableState getTableState(Result r) throws IOException {
   }
 
   /**
-   * @return Deserialized values of <qualifier,regioninfo> pairs taken from column values that
-   *         match the regex 'info:merge.*' in array of <code>cells</code>.
+   * Return deserialized values of &lt;qualifier,regioninfo&gt; pairs taken from column values that
+   * match the regex 'info:merge.*' in array of <code>cells</code>.
    */
   @Nullable
   public static Map<String, RegionInfo> getMergeRegionsWithName(Cell[] cells) {
@@ -376,8 +376,8 @@ public static Map<String, RegionInfo> getMergeRegionsWithName(Cell[] cells) {
   }
 
   /**
-   * @return Deserialized regioninfo values taken from column values that match the regex
-   *         'info:merge.*' in array of <code>cells</code>.
+   * Return deserialized regioninfo values taken from column values that match the regex
+   * 'info:merge.*' in array of <code>cells</code>.
    */
   @Nullable
   public static List<RegionInfo> getMergeRegions(Cell[] cells) {
@@ -386,8 +386,8 @@ public static List<RegionInfo> getMergeRegions(Cell[] cells) {
   }
 
   /**
-   * @return True if any merge regions present in <code>cells</code>; i.e. the column in
-   *         <code>cell</code> matches the regex 'info:merge.*'.
+   * Return true if any merge regions present in <code>cells</code>; i.e. the column in
+   * <code>cell</code> matches the regex 'info:merge.*'.
    */
   public static boolean hasMergeRegions(Cell[] cells) {
     for (Cell cell : cells) {
@@ -399,7 +399,7 @@ public static boolean hasMergeRegions(Cell[] cells) {
   }
 
   /**
-   * @return True if the column in <code>cell</code> matches the regex 'info:merge.*'.
+   * Return true if the column in <code>cell</code> matches the regex 'info:merge.*'.
    */
   public static boolean isMergeQualifierPrefix(Cell cell) {
     // Check to see if has family and that qualifier starts with the merge qualifier 'merge'

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

@@ -59,6 +59,7 @@ private ClientMetaTableAccessor() {
   }
 
   @InterfaceAudience.Private
+  @SuppressWarnings("ImmutableEnumChecker")
   public enum QueryType {
     ALL(HConstants.TABLE_FAMILY, HConstants.CATALOG_FAMILY),
     REGION(HConstants.CATALOG_FAMILY),
@@ -101,8 +102,7 @@ public static CompletableFuture<Optional<TableState>> getTableState(AsyncTable<?
   }
 
   /**
-   * Returns the HRegionLocation from meta for the given region n * @param regionName region we're
-   * looking for
+   * Returns the HRegionLocation from meta for the given region we're looking for
    * @return HRegionLocation for the given region
    */
   public static CompletableFuture<Optional<HRegionLocation>>
@@ -127,8 +127,7 @@ public static CompletableFuture<Optional<TableState>> getTableState(AsyncTable<?
   }
 
   /**
-   * Returns the HRegionLocation from meta for the given encoded region name n * @param
-   * encodedRegionName region we're looking for
+   * Returns the HRegionLocation from meta for the given encoded region name we're looking for
    * @return HRegionLocation for the given region
    */
   public static CompletableFuture<Optional<HRegionLocation>>
@@ -167,8 +166,8 @@ private static Optional<TableState> getTableState(Result r) throws IOException {
   }
 
   /**
-   * Used to get all region locations for the specific table. n * @param tableName table we're
-   * looking for, can be null for getting all regions
+   * Used to get all region locations for the specific table we're looking for. Can be null for
+   * getting all regions.
    * @return the list of region locations. The return value will be wrapped by a
    *         {@link CompletableFuture}.
    */
@@ -191,9 +190,8 @@ public static CompletableFuture<List<HRegionLocation>> getTableHRegionLocations(
   }
 
   /**
-   * Used to get table regions' info and server. n * @param tableName table we're looking for, can
-   * be null for getting all regions
-   * @param excludeOfflinedSplitParents don't return split parents
+   * Used to get table regions' info and server for the table we're looking for. Can be null for
+   * getting all regions.
    * @return the list of regioninfos and server. The return value will be wrapped by a
    *         {@link CompletableFuture}.
    */
@@ -220,24 +218,12 @@ private static CompletableFuture<List<Pair<RegionInfo, ServerName>>> getTableReg
     return future;
   }
 
-  /**
-   * Performs a scan of META table for given table. n * @param tableName table withing we scan
-   * @param type    scanned part of meta
-   * @param visitor Visitor invoked against each row
-   */
   private static CompletableFuture<Void> scanMeta(AsyncTable<AdvancedScanResultConsumer> metaTable,
     TableName tableName, QueryType type, final Visitor visitor) {
     return scanMeta(metaTable, getTableStartRowForMeta(tableName, type),
       getTableStopRowForMeta(tableName, type), type, Integer.MAX_VALUE, visitor);
   }
 
-  /**
-   * Performs a scan of META table for given table. n * @param startRow Where to start the scan
-   * @param stopRow Where to stop the scan
-   * @param type    scanned part of meta
-   * @param maxRows maximum rows to return
-   * @param visitor Visitor invoked against each row
-   */
   private static CompletableFuture<Void> scanMeta(AsyncTable<AdvancedScanResultConsumer> metaTable,
     byte[] startRow, byte[] stopRow, QueryType type, int maxRows, final Visitor visitor) {
     int rowUpperLimit = maxRows > 0 ? maxRows : Integer.MAX_VALUE;
@@ -383,7 +369,7 @@ public boolean visit(Result r) throws IOException {
     abstract void add(Result r);
 
     /**
-     * @return Collected results; wait till visits complete to collect all possible results
+     * Return collected results; wait till visits complete to collect all possible results
      */
     List<T> getResults() {
       return this.results;
@@ -468,6 +454,7 @@ private static Optional<RegionLocations> getRegionLocations(Result r) {
   }
 
   /**
+   * Determine the start row for scanning META according to query type
    * @param tableName table we're working with
    * @return start row for scanning META according to query type
    */
@@ -493,6 +480,7 @@ public static byte[] getTableStartRowForMeta(TableName tableName, QueryType type
   }
 
   /**
+   * Determine the stop row for scanning META according to query type
    * @param tableName table we're working with
    * @return stop row for scanning META according to query type
    */

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

@@ -34,9 +34,7 @@
 public class ClusterId {
   private final String id;
 
-  /**
-   * New ClusterID. Generates a uniqueid.
-   */
+  /** New ClusterID. Generates a unique UUID. */
   public ClusterId() {
     this(UUID.randomUUID().toString());
   }
@@ -45,16 +43,16 @@ public ClusterId(final String uuid) {
     this.id = uuid;
   }
 
-  /**
-   * @return The clusterid serialized using pb w/ pb magic prefix
-   */
+  /** Return the cluster id serialized using pb with the pb magic prefix */
   public byte[] toByteArray() {
     return ProtobufUtil.prependPBMagic(convert().toByteArray());
   }
 
   /**
+   * Parse a serialized representation of the cluster id.
    * @param bytes A pb serialized {@link ClusterId} instance with pb magic prefix
-   * @return An instance of {@link ClusterId} made from <code>bytes</code> n * @see #toByteArray()
+   * @return An instance of {@link ClusterId} made from <code>bytes</code>
+   * @see #toByteArray()
    */
   public static ClusterId parseFrom(final byte[] bytes) throws DeserializationException {
     if (ProtobufUtil.isPBMagicPrefix(bytes)) {
@@ -74,24 +72,17 @@ public static ClusterId parseFrom(final byte[] bytes) throws DeserializationExce
     }
   }
 
-  /**
-   * @return A pb instance to represent this instance.
-   */
+  /** Return a pb instance to represent this instance. */
   public ClusterIdProtos.ClusterId convert() {
     ClusterIdProtos.ClusterId.Builder builder = ClusterIdProtos.ClusterId.newBuilder();
     return builder.setClusterId(this.id).build();
   }
 
-  /**
-   * n * @return A {@link ClusterId} made from the passed in <code>cid</code>
-   */
+  /** Return a {@link ClusterId} made from the passed in <code>cid</code> */
   public static ClusterId convert(final ClusterIdProtos.ClusterId cid) {
     return new ClusterId(cid.getClusterId());
   }
 
-  /**
-   * @see java.lang.Object#toString()
-   */
   @Override
   public String toString() {
     return this.id;

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

@@ -70,36 +70,36 @@
 public interface ClusterMetrics {
 
   /**
-   * @return the HBase version string as reported by the HMaster
+   * Return the HBase version string as reported by the master.
    */
   @Nullable
   String getHBaseVersion();
 
   /**
-   * @return the names of region servers on the dead list
+   * Return the names of region servers on the dead list.
    */
   List<ServerName> getDeadServerNames();
 
   /**
-   * @return the names of region servers on the decommissioned list
+   * Return the names of region servers on the decommissioned list.
    */
   List<ServerName> getDecommissionedServerNames();
 
   /**
-   * @return the names of region servers on the live list
+   * Return the names of region servers on the live list.
    */
   Map<ServerName, ServerMetrics> getLiveServerMetrics();
 
   /**
-   * @return the number of regions deployed on the cluster
+   * Return the number of regions deployed on the cluster.
    */
   default int getRegionCount() {
     return getLiveServerMetrics().entrySet().stream()
       .mapToInt(v -> v.getValue().getRegionMetrics().size()).sum();
   }
 
   /**
-   * @return the number of requests since last report
+   * Return the number of requests since the last report.
    */
   default long getRequestCount() {
     return getLiveServerMetrics().entrySet().stream()
@@ -115,7 +115,7 @@ default long getRequestCount() {
   ServerName getMasterName();
 
   /**
-   * @return the names of backup masters
+   * Return the names of the backup masters.
    */
   List<ServerName> getBackupMasterNames();
 
@@ -148,7 +148,7 @@ default long getLastMajorCompactionTimestamp(byte[] regionName) {
   List<ServerName> getServersName();
 
   /**
-   * @return the average cluster load
+   * Return the average cluster load.
    */
   default double getAverageLoad() {
     int serverSize = getLiveServerMetrics().size();
@@ -159,7 +159,7 @@ default double getAverageLoad() {
   }
 
   /**
-   * Provide region states count for given table. e.g howmany regions of give table are
+   * Provide region states count for given table. e.g how many regions of give table are
    * opened/closed/rit etc
    * @return map of table to region states count
    */

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

@@ -67,13 +67,13 @@ public static ClusterStatusProtos.ClusterStatus toClusterStatus(ClusterMetrics m
           .collect(Collectors.toList()))
         .addAllTableRegionStatesCount(metrics.getTableRegionStatesCount().entrySet().stream()
           .map(status -> ClusterStatusProtos.TableRegionStatesCount.newBuilder()
-            .setTableName(ProtobufUtil.toProtoTableName((status.getKey())))
+            .setTableName(ProtobufUtil.toProtoTableName(status.getKey()))
             .setRegionStatesCount(ProtobufUtil.toTableRegionStatesCount(status.getValue())).build())
           .collect(Collectors.toList()))
         .addAllDecommissionedServers(metrics.getDecommissionedServerNames().stream()
           .map(ProtobufUtil::toServerName).collect(Collectors.toList()));
     if (metrics.getMasterName() != null) {
-      builder.setMaster(ProtobufUtil.toServerName((metrics.getMasterName())));
+      builder.setMaster(ProtobufUtil.toServerName(metrics.getMasterName()));
     }
     if (metrics.getMasterTasks() != null) {
       builder.addAllMasterTasks(metrics.getMasterTasks().stream()

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

@@ -28,29 +28,25 @@
 @InterfaceStability.Evolving
 public interface CoprocessorEnvironment<C extends Coprocessor> {
 
-  /** @return the Coprocessor interface version */
+  /** Return the coprocessor interface version */
   int getVersion();
 
-  /** @return the HBase version as a string (e.g. "0.21.0") */
+  /** Return the HBase version as a string (e.g. "0.21.0") */
   String getHBaseVersion();
 
-  /** @return the loaded coprocessor instance */
+  /** Return the loaded coprocessor instance */
   C getInstance();
 
-  /** @return the priority assigned to the loaded coprocessor */
+  /** Return the priority assigned to the loaded coprocessor */
   int getPriority();
 
-  /** @return the load sequence number */
+  /** Return the load sequence number */
   int getLoadSequence();
 
-  /**
-   * @return a Read-only Configuration; throws {@link UnsupportedOperationException} if you try to
-   *         set a configuration.
-   */
+  /** Return a read-only Configuration. */
   Configuration getConfiguration();
 
-  /**
-   * @return the classloader for the loaded coprocessor instance
-   */
+  /** Return the classloader for the loaded coprocessor instance */
   ClassLoader getClassLoader();
+
 }