HBASE-27235 Clean up error-prone warnings in hbase-hadoop-compat (#4648)

Signed-off-by: Duo Zhang <zhangduo@apache.org>

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/CompatibilitySingletonFactory.java

@@ -31,6 +31,8 @@ import org.slf4j.LoggerFactory;
  */
 @InterfaceAudience.Private
 public class CompatibilitySingletonFactory extends CompatibilityFactory {
+
+  @SuppressWarnings("ImmutableEnumChecker")
   public static enum SingletonStorage {
     INSTANCE;
 

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerSourceFactoryImpl.java

@@ -23,10 +23,12 @@ import org.apache.yetus.audience.InterfaceAudience;
 
 @InterfaceAudience.Private
 public class MetricsHBaseServerSourceFactoryImpl extends MetricsHBaseServerSourceFactory {
+
+  @SuppressWarnings("ImmutableEnumChecker")
   private enum SourceStorage {
     INSTANCE;
 
-    HashMap<String, MetricsHBaseServerSource> sources = new HashMap<>();
+    private final HashMap<String, MetricsHBaseServerSource> sources = new HashMap<>();
   }
 
   @Override

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/mapreduce/JobUtil.java

@@ -24,8 +24,6 @@ import org.apache.hadoop.mapreduce.Cluster;
 import org.apache.hadoop.mapreduce.JobSubmissionFiles;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Utility methods to interact with a job.
@@ -33,7 +31,6 @@ import org.slf4j.LoggerFactory;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public abstract class JobUtil {
-  private static final Logger LOG = LoggerFactory.getLogger(JobUtil.class);
 
   protected JobUtil() {
     super();

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsAssignmentManagerSourceImpl.java

@@ -66,6 +66,7 @@ public class MetricsAssignmentManagerSourceImpl extends BaseSourceImpl
     super(metricsName, metricsDescription, metricsContext, metricsJmxContext);
   }
 
+  @Override
   public void init() {
     ritGauge = metricsRegistry.newGauge(RIT_COUNT_NAME, RIT_COUNT_DESC, 0L);
     ritCountOverThresholdGauge =

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterSourceFactoryImpl.java

@@ -24,10 +24,12 @@ import org.apache.yetus.audience.InterfaceAudience;
  */
 @InterfaceAudience.Private
 public class MetricsMasterSourceFactoryImpl implements MetricsMasterSourceFactory {
+
+  @SuppressWarnings("ImmutableEnumChecker")
   private static enum FactoryStorage {
     INSTANCE;
 
-    MetricsMasterSource masterSource;
+    private MetricsMasterSource masterSource;
   }
 
   @Override

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/balancer/MetricsStochasticBalancerSourceImpl.java

@@ -64,6 +64,7 @@ public class MetricsStochasticBalancerSourceImpl extends MetricsBalancerSourceIm
   /**
    * Reports stochastic load balancer costs to JMX
    */
+  @Override
   public void updateStochasticCost(String tableName, String costFunctionName, String functionDesc,
     Double cost) {
     if (tableName == null || costFunctionName == null || cost == null) {

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/metrics/BaseSourceImpl.java

@@ -39,6 +39,7 @@ import org.apache.yetus.audience.InterfaceAudience;
 @InterfaceAudience.Private
 public class BaseSourceImpl implements BaseSource, MetricsSource {
 
+  @SuppressWarnings("ImmutableEnumChecker")
   private static enum DefaultMetricsSystemInitializer {
     INSTANCE;
 
@@ -121,6 +122,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
 
   }
 
+  @Override
   public void init() {
     this.metricsRegistry.clearMetrics();
   }
@@ -130,6 +132,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
    * @param gaugeName gauge name
    * @param value     the new value of the gauge.
    */
+  @Override
   public void setGauge(String gaugeName, long value) {
     MutableGaugeLong gaugeInt = metricsRegistry.getGauge(gaugeName, value);
     gaugeInt.set(value);
@@ -140,6 +143,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
    * @param gaugeName The name of the gauge to increment.
    * @param delta     The amount to increment the gauge by.
    */
+  @Override
   public void incGauge(String gaugeName, long delta) {
     MutableGaugeLong gaugeInt = metricsRegistry.getGauge(gaugeName, 0L);
     gaugeInt.incr(delta);
@@ -150,6 +154,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
    * @param gaugeName The name of the gauge.
    * @param delta     the ammount to subtract from a gauge value.
    */
+  @Override
   public void decGauge(String gaugeName, long delta) {
     MutableGaugeLong gaugeInt = metricsRegistry.getGauge(gaugeName, 0L);
     gaugeInt.decr(delta);
@@ -160,6 +165,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
    * @param key   the name of the counter
    * @param delta the ammount to increment
    */
+  @Override
   public void incCounters(String key, long delta) {
     MutableFastCounter counter = metricsRegistry.getCounter(key, 0L);
     counter.incr(delta);
@@ -176,6 +182,7 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
    * Remove a named gauge.
    * @param key the key of the gauge to remove
    */
+  @Override
   public void removeMetric(String key) {
     metricsRegistry.removeMetric(key);
     JmxCacheBuster.clearJmxCache();
@@ -190,18 +197,22 @@ public class BaseSourceImpl implements BaseSource, MetricsSource {
     return metricsRegistry;
   }
 
+  @Override
   public String getMetricsContext() {
     return metricsContext;
   }
 
+  @Override
   public String getMetricsDescription() {
     return metricsDescription;
   }
 
+  @Override
   public String getMetricsJmxContext() {
     return metricsJmxContext;
   }
 
+  @Override
   public String getMetricsName() {
     return metricsName;
   }

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/metrics/Interns.java

@@ -39,6 +39,7 @@ public final class Interns {
   private static LoadingCache<String, ConcurrentHashMap<String, MetricsInfo>> infoCache =
     CacheBuilder.newBuilder().expireAfterAccess(1, TimeUnit.DAYS)
       .build(new CacheLoader<String, ConcurrentHashMap<String, MetricsInfo>>() {
+        @Override
         public ConcurrentHashMap<String, MetricsInfo> load(String key) {
           return new ConcurrentHashMap<>();
         }
@@ -46,6 +47,7 @@ public final class Interns {
   private static LoadingCache<MetricsInfo, ConcurrentHashMap<String, MetricsTag>> tagCache =
     CacheBuilder.newBuilder().expireAfterAccess(1, TimeUnit.DAYS)
       .build(new CacheLoader<MetricsInfo, ConcurrentHashMap<String, MetricsTag>>() {
+        @Override
         public ConcurrentHashMap<String, MetricsTag> load(MetricsInfo key) {
           return new ConcurrentHashMap<>();
         }

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionAggregateSourceImpl.java

@@ -52,6 +52,7 @@ public class MetricsRegionAggregateSourceImpl extends BaseSourceImpl
 
     // Every few mins clean the JMX cache.
     executor.getExecutor().scheduleWithFixedDelay(new Runnable() {
+      @Override
       public void run() {
         JmxCacheBuster.clearJmxCache();
       }

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionServerSourceFactoryImpl.java

@@ -27,10 +27,12 @@ import org.apache.yetus.audience.InterfaceAudience;
  */
 @InterfaceAudience.Private
 public class MetricsRegionServerSourceFactoryImpl implements MetricsRegionServerSourceFactory {
+
+  @SuppressWarnings("ImmutableEnumChecker")
   public static enum FactoryStorage {
     INSTANCE;
 
-    private Object aggLock = new Object();
+    private final Object aggLock = new Object();
     private MetricsRegionAggregateSourceImpl regionAggImpl;
     private MetricsUserAggregateSourceImpl userAggImpl;
     private MetricsTableAggregateSourceImpl tblAggImpl;
@@ -46,6 +48,7 @@ public class MetricsRegionServerSourceFactoryImpl implements MetricsRegionServer
     }
   }
 
+  @Override
   public synchronized MetricsUserAggregateSourceImpl getUserAggregate() {
     synchronized (FactoryStorage.INSTANCE.aggLock) {
       if (FactoryStorage.INSTANCE.userAggImpl == null) {
@@ -91,6 +94,7 @@ public class MetricsRegionServerSourceFactoryImpl implements MetricsRegionServer
     return new MetricsTableSourceImpl(table, getTableAggregate(), wrapper);
   }
 
+  @Override
   public MetricsIOSource createIO(MetricsIOWrapper wrapper) {
     return new MetricsIOSourceImpl(wrapper);
   }

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionWrapper.java

@@ -116,13 +116,13 @@ public interface MetricsRegionWrapper {
   long getNumCompactionsFailed();
 
   /**
-   * @return the total number of compactions that are currently queued(or being executed) at point
+   * Returns the total number of compactions that are currently queued(or being executed) at point
    * in time
    */
   long getNumCompactionsQueued();
 
   /**
-   * @return the total number of flushes currently queued(being executed) for this region at point
+   * Returns the total number of flushes currently queued(being executed) for this region at point
    * in time
    */
   long getNumFlushesQueued();
@@ -150,7 +150,7 @@ public interface MetricsRegionWrapper {
   long getStoreRefCount();
 
   /**
-   * @return the max number of references active on any store file among all compacted store files
+   * Returns the max number of references active on any store file among all compacted store files
    * that belong to this region
    */
   long getMaxCompactedStoreFileRefCount();

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsTableAggregateSourceImpl.java

@@ -43,10 +43,6 @@ public class MetricsTableAggregateSourceImpl extends BaseSourceImpl
     super(metricsName, metricsDescription, metricsContext, metricsJmxContext);
   }
 
-  private void register(MetricsTableSource source) {
-    source.registerMetrics();
-  }
-
   @Override
   public void deleteTableSource(String table) {
     try {

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsTableSourceImpl.java

@@ -74,6 +74,9 @@ import org.apache.yetus.audience.InterfaceAudience;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterables;
+
 @InterfaceAudience.Private
 public class MetricsTableSourceImpl implements MetricsTableSource {
 
@@ -354,8 +357,9 @@ public class MetricsTableSourceImpl implements MetricsTableSource {
       for (Entry<String, Long> entry : metricMap.entrySet()) {
         // append 'store' and its name to the metric
         mrb.addGauge(Interns.info(this.tableNamePrefixPart1 + _COLUMNFAMILY
-          + entry.getKey().split(MetricsTableWrapperAggregate.HASH)[1] + this.tableNamePrefixPart2
-          + metricName, metricDesc), entry.getValue());
+          + Iterables
+            .get(Splitter.onPattern(MetricsTableWrapperAggregate.HASH).split(entry.getKey()), 1)
+          + this.tableNamePrefixPart2 + metricName, metricDesc), entry.getValue());
       }
     }
   }
@@ -375,11 +379,9 @@ public class MetricsTableSourceImpl implements MetricsTableSource {
     if (this == o) {
       return true;
     }
-
-    if (o == null || getClass() != o.getClass()) {
+    if (!(o instanceof MetricsTableSourceImpl)) {
       return false;
     }
-
     return (compareTo((MetricsTableSourceImpl) o) == 0);
   }
 

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsUserSourceImpl.java

@@ -57,7 +57,6 @@ public class MetricsUserSourceImpl implements MetricsUserSource {
   private final int hashCode;
 
   private AtomicBoolean closed = new AtomicBoolean(false);
-  private final MetricsUserAggregateSourceImpl agg;
   private final DynamicMetricsRegistry registry;
 
   private ConcurrentHashMap<String, ClientMetrics> clientMetricsMap;
@@ -115,7 +114,6 @@ public class MetricsUserSourceImpl implements MetricsUserSource {
     }
 
     this.user = user;
-    this.agg = agg;
     this.registry = agg.getMetricsRegistry();
 
     this.userNamePrefix = "user_" + user + "_metric_";

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/replication/regionserver/MetricsReplicationSourceFactoryImpl.java

@@ -22,10 +22,11 @@ import org.apache.yetus.audience.InterfaceAudience;
 @InterfaceAudience.Private
 public class MetricsReplicationSourceFactoryImpl implements MetricsReplicationSourceFactory {
 
+  @SuppressWarnings("ImmutableEnumChecker")
   private static enum SourceHolder {
     INSTANCE;
 
-    final MetricsReplicationSourceImpl source = new MetricsReplicationSourceImpl();
+    private final MetricsReplicationSourceImpl source = new MetricsReplicationSourceImpl();
   }
 
   @Override

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/thrift/MetricsThriftServerSourceFactoryImpl.java

@@ -29,11 +29,12 @@ public class MetricsThriftServerSourceFactoryImpl implements MetricsThriftServer
    * A singleton used to make sure that only one thrift metrics source per server type is ever
    * created.
    */
+  @SuppressWarnings("ImmutableEnumChecker")
   private enum FactoryStorage {
     INSTANCE;
 
-    MetricsThriftServerSourceImpl thriftOne;
-    MetricsThriftServerSourceImpl thriftTwo;
+    private MetricsThriftServerSourceImpl thriftOne;
+    private MetricsThriftServerSourceImpl thriftTwo;
   }
 
   @Override

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/zookeeper/MetricsZooKeeperSourceImpl.java

@@ -83,6 +83,7 @@ public class MetricsZooKeeperSourceImpl extends BaseSourceImpl implements Metric
       SYNC_OPERATION_LATENCY_DESC);
   }
 
+  @Override
   public void getMetrics(MetricsCollector metricsCollector, boolean all) {
     super.getMetrics(metricsCollector, all);
     clearZKExceptionMetrics();

hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/DefaultMetricsSystemHelper.java

@@ -33,6 +33,7 @@ public class DefaultMetricsSystemHelper {
   private final Field mapField;
 
   public DefaultMetricsSystemHelper() {
+    @SuppressWarnings("GetClassOnEnum")
     Class<? extends DefaultMetricsSystem> clazz = DefaultMetricsSystem.INSTANCE.getClass();
     Method m;
     try {

hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/DynamicMetricsRegistry.java

@@ -26,8 +26,6 @@ import org.apache.hadoop.metrics2.MetricsRecordBuilder;
 import org.apache.hadoop.metrics2.MetricsTag;
 import org.apache.hadoop.metrics2.impl.MsInfo;
 import org.apache.yetus.audience.InterfaceAudience;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.base.MoreObjects;
 import org.apache.hbase.thirdparty.com.google.common.collect.Maps;
@@ -43,7 +41,6 @@ import org.apache.hbase.thirdparty.com.google.common.collect.Maps;
  */
 @InterfaceAudience.Private
 public class DynamicMetricsRegistry {
-  private static final Logger LOG = LoggerFactory.getLogger(DynamicMetricsRegistry.class);
 
   private final ConcurrentMap<String, MutableMetric> metricsMap = Maps.newConcurrentMap();
   private final ConcurrentMap<String, MetricsTag> tagsMap = Maps.newConcurrentMap();

hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MetricsExecutorImpl.java

@@ -43,6 +43,7 @@ public class MetricsExecutorImpl implements MetricsExecutor {
     }
   }
 
+  @SuppressWarnings("ImmutableEnumChecker")
   private enum ExecutorSingleton {
     INSTANCE;
 

hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MutableHistogram.java

@@ -46,6 +46,7 @@ public class MutableHistogram extends MutableMetric implements MetricHistogram {
     this.histogram = new HistogramImpl();
   }
 
+  @Override
   public void add(final long val) {
     histogram.update(val);
   }

hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/util/MetricSampleQuantiles.java

@@ -35,6 +35,7 @@ import org.apache.yetus.audience.InterfaceAudience;
  * summaries" in SIGMOD 2001
  */
 @InterfaceAudience.Private
+@SuppressWarnings("JdkObsolete") // This is a use case for LinkedList
 public class MetricSampleQuantiles {
 
   /**

hbase-hadoop-compat/src/test/java/org/apache/hadoop/hbase/HadoopShims.java

@@ -30,6 +30,7 @@ public interface HadoopShims {
    *               TaskAttemptId.forName()
    * @return a concrete TaskAttemptContext instance of o.a.h.mapreduce.TaskAttemptContext
    */
+  @SuppressWarnings("TypeParameterUnusedInFormals")
   <T, J> T createTestTaskAttemptContext(final J job, final String taskId);
 
 }

hbase-hadoop-compat/src/test/java/org/apache/hadoop/hbase/HadoopShimsImpl.java

@@ -33,7 +33,7 @@ public class HadoopShimsImpl implements HadoopShims {
    * @return a concrete TaskAttemptContext instance of o.a.h.mapreduce.TaskAttemptContext
    */
   @Override
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({ "unchecked", "TypeParameterUnusedInFormals" })
   public <T, J> T createTestTaskAttemptContext(J job, String taskId) {
     Job j = (Job) job;
     return (T) new TaskAttemptContextImpl(j.getConfiguration(), TaskAttemptID.forName(taskId));

hbase-hadoop-compat/src/test/java/org/apache/hadoop/hbase/TestCompatibilitySingletonFactory.java

@@ -41,7 +41,7 @@ public class TestCompatibilitySingletonFactory {
 
   private static final int ITERATIONS = 100000;
 
-  private class TestCompatibilitySingletonFactoryCallable implements Callable<String> {
+  private static class TestCompatibilitySingletonFactoryCallable implements Callable<String> {
 
     @Override
     public String call() throws Exception {