Revert "HBASE-27093 AsyncNonMetaRegionLocator：put Complete CompletableFuture outside lock block (apache#4496)"

This reverts commit 1e5147a.

Author: wenwj0

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

@@ -35,12 +35,10 @@
 import static org.apache.hadoop.hbase.util.ConcurrentMapUtils.computeIfAbsent;
 
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
@@ -124,26 +122,6 @@ public boolean equals(Object obj) {
     }
   }
 
-  private static final class RegionLocationsFutureResult {
-    private final CompletableFuture<RegionLocations> future;
-    private final RegionLocations result;
-    private final Throwable e;
-
-    public RegionLocationsFutureResult(CompletableFuture<RegionLocations> future,
-      RegionLocations result, Throwable e) {
-      this.future = future;
-      this.result = result;
-      this.e = e;
-    }
-
-    public void complete() {
-      if (e != null) {
-        future.completeExceptionally(e);
-      }
-      future.complete(result);
-    }
-  }
-
   private static final class TableCache {
 
     private final ConcurrentNavigableMap<byte[], RegionLocations> cache =
@@ -170,20 +148,18 @@ public Optional<LocateRequest> getCandidate() {
       return allRequests.keySet().stream().filter(r -> !isPending(r)).findFirst();
     }
 
-    public List<RegionLocationsFutureResult> clearCompletedRequests(RegionLocations locations) {
-      List<RegionLocationsFutureResult> futureResultList = new ArrayList<>();
+    public void clearCompletedRequests(RegionLocations locations) {
       for (Iterator<Map.Entry<LocateRequest, CompletableFuture<RegionLocations>>> iter =
         allRequests.entrySet().iterator(); iter.hasNext();) {
         Map.Entry<LocateRequest, CompletableFuture<RegionLocations>> entry = iter.next();
-        if (tryComplete(entry.getKey(), entry.getValue(), locations, futureResultList)) {
+        if (tryComplete(entry.getKey(), entry.getValue(), locations)) {
           iter.remove();
         }
       }
-      return futureResultList;
     }
 
     private boolean tryComplete(LocateRequest req, CompletableFuture<RegionLocations> future,
-      RegionLocations locations, List<RegionLocationsFutureResult> futureResultList) {
+      RegionLocations locations) {
       if (future.isDone()) {
         return true;
       }
@@ -209,7 +185,7 @@ private boolean tryComplete(LocateRequest req, CompletableFuture<RegionLocations
         completed = loc.getRegion().containsRow(req.row);
       }
       if (completed) {
-        futureResultList.add(new RegionLocationsFutureResult(future, locations, null));
+        future.complete(locations);
         return true;
       } else {
         return false;
@@ -343,36 +319,32 @@ private void complete(TableName tableName, LocateRequest req, RegionLocations lo
     TableCache tableCache = getTableCache(tableName);
     if (locs != null) {
       RegionLocations addedLocs = addToCache(tableCache, locs);
-      List<RegionLocationsFutureResult> futureResultList = new ArrayList<>();
       synchronized (tableCache) {
         tableCache.pendingRequests.remove(req);
-        futureResultList.addAll(tableCache.clearCompletedRequests(addedLocs));
+        tableCache.clearCompletedRequests(addedLocs);
         // Remove a complete locate request in a synchronized block, so the table cache must have
         // quota to send a candidate request.
         toSend = tableCache.getCandidate();
         toSend.ifPresent(r -> tableCache.send(r));
       }
-      futureResultList.forEach(RegionLocationsFutureResult::complete);
       toSend.ifPresent(r -> locateInMeta(tableName, r));
     } else {
       // we meet an error
       assert error != null;
-      List<RegionLocationsFutureResult> futureResultList = new ArrayList<>();
       synchronized (tableCache) {
         tableCache.pendingRequests.remove(req);
         // fail the request itself, no matter whether it is a DoNotRetryIOException, as we have
         // already retried several times
-        CompletableFuture<RegionLocations> future = tableCache.allRequests.remove(req);
+        CompletableFuture<?> future = tableCache.allRequests.remove(req);
         if (future != null) {
-          futureResultList.add(new RegionLocationsFutureResult(future, null, error));
+          future.completeExceptionally(error);
         }
-        futureResultList.addAll(tableCache.clearCompletedRequests(null));
+        tableCache.clearCompletedRequests(null);
         // Remove a complete locate request in a synchronized block, so the table cache must have
         // quota to send a candidate request.
         toSend = tableCache.getCandidate();
         toSend.ifPresent(r -> tableCache.send(r));
       }
-      futureResultList.forEach(RegionLocationsFutureResult::complete);
       toSend.ifPresent(r -> locateInMeta(tableName, r));
     }
   }
@@ -570,11 +542,9 @@ public void onNext(Result[] results, ScanController controller) {
               continue;
             }
             RegionLocations addedLocs = addToCache(tableCache, locs);
-            List<RegionLocationsFutureResult> futureResultList = new ArrayList<>();
             synchronized (tableCache) {
-              futureResultList.addAll(tableCache.clearCompletedRequests(addedLocs));
+              tableCache.clearCompletedRequests(addedLocs);
             }
-            futureResultList.forEach(RegionLocationsFutureResult::complete);
           }
         }
       }
@@ -706,16 +676,12 @@ void clearCache(TableName tableName) {
     if (tableCache == null) {
       return;
     }
-    List<RegionLocationsFutureResult> futureResultList = new ArrayList<>();
     synchronized (tableCache) {
       if (!tableCache.allRequests.isEmpty()) {
         IOException error = new IOException("Cache cleared");
-        tableCache.allRequests.values().forEach(f -> {
-          futureResultList.add(new RegionLocationsFutureResult(f, null, error));
-        });
+        tableCache.allRequests.values().forEach(f -> f.completeExceptionally(error));
       }
     }
-    futureResultList.forEach(RegionLocationsFutureResult::complete);
     conn.getConnectionMetrics()
       .ifPresent(metrics -> metrics.incrMetaCacheNumClearRegion(tableCache.cache.size()));
   }