Replace FutureUtil method with standard library equivalent (#390)

Signed-off-by: Ratan Rai Sur <ratan.r.sur@gmail.com>

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/task/AbstractEthTask.java

@@ -14,8 +14,6 @@
  */
 package org.hyperledger.besu.ethereum.eth.manager.task;
 
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
-
 import org.hyperledger.besu.ethereum.eth.manager.EthScheduler;
 import org.hyperledger.besu.metrics.BesuMetricCategory;
 import org.hyperledger.besu.metrics.noop.NoOpMetricsSystem;
@@ -127,7 +125,7 @@ public abstract class AbstractEthTask<T> implements EthTask<T> {
         subTaskFuture.whenComplete((r, t) -> subTaskFutures.remove(subTaskFuture));
         return subTaskFuture;
       } else {
-        return completedExceptionally(new CancellationException());
+        return CompletableFuture.failedFuture(new CancellationException());
       }
     }
   }

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/task/GetBlockFromPeerTask.java

@@ -14,8 +14,6 @@
  */
 package org.hyperledger.besu.ethereum.eth.manager.task;
 
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
-
 import org.hyperledger.besu.ethereum.core.Block;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.core.Hash;
@@ -102,7 +100,7 @@ public class GetBlockFromPeerTask extends AbstractPeerTask<Block> {
   private CompletableFuture<PeerTaskResult<List<Block>>> completeBlock(
       final PeerTaskResult<List<BlockHeader>> headerResult) {
     if (headerResult.getResult().isEmpty()) {
-      return completedExceptionally(new IncompleteResultsException());
+      return CompletableFuture.failedFuture(new IncompleteResultsException());
     }
 
     return executeSubTask(

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/PipelineChainDownloader.java

@@ -15,7 +15,6 @@
 package org.hyperledger.besu.ethereum.eth.sync;
 
 import static java.util.concurrent.CompletableFuture.completedFuture;
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
 import static org.hyperledger.besu.util.FutureUtils.exceptionallyCompose;
 
 import org.hyperledger.besu.ethereum.eth.manager.EthScheduler;
@@ -134,7 +133,7 @@ public class PipelineChainDownloader<C> implements ChainDownloader {
 
     logDownloadFailure("Chain download failed.", error);
     // Propagate the error out, terminating this chain download.
-    return completedExceptionally(error);
+    return CompletableFuture.failedFuture(error);
   }
 
   private void logDownloadFailure(final String message, final Throwable error) {
@@ -152,7 +151,8 @@ public class PipelineChainDownloader<C> implements ChainDownloader {
 
   private synchronized CompletionStage<Void> startDownloadForSyncTarget(final SyncTarget target) {
     if (cancelled.get()) {
-      return completedExceptionally(new CancellationException("Chain download was cancelled"));
+      return CompletableFuture.failedFuture(
+          new CancellationException("Chain download was cancelled"));
     }
     syncState.setSyncTarget(target.peer(), target.commonAncestor());
     currentDownloadPipeline = downloadPipelineFactory.createDownloadPipelineForSyncTarget(target);

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/fastsync/FastSyncActions.java

@@ -15,7 +15,6 @@
 package org.hyperledger.besu.ethereum.eth.sync.fastsync;
 
 import static java.util.concurrent.CompletableFuture.completedFuture;
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
 import static org.hyperledger.besu.util.FutureUtils.exceptionallyCompose;
 
 import org.hyperledger.besu.ethereum.ProtocolContext;
@@ -103,7 +102,7 @@ public class FastSyncActions<C> {
           if (ExceptionUtils.rootCause(throwable) instanceof TimeoutException) {
             return waitForAnyPeer();
           }
-          return completedExceptionally(throwable);
+          return CompletableFuture.failedFuture(throwable);
         });
   }
 

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/fastsync/FastSyncDownloader.java

@@ -14,7 +14,6 @@
  */
 package org.hyperledger.besu.ethereum.eth.sync.fastsync;
 
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
 import static org.hyperledger.besu.util.FutureUtils.exceptionallyCompose;
 
 import org.hyperledger.besu.ethereum.eth.sync.ChainDownloader;
@@ -90,7 +89,7 @@ public class FastSyncDownloader<C> {
   private CompletableFuture<FastSyncState> handleFailure(final Throwable error) {
     trailingPeerRequirements = Optional.empty();
     if (ExceptionUtils.rootCause(error) instanceof FastSyncException) {
-      return completedExceptionally(error);
+      return CompletableFuture.failedFuture(error);
     } else if (ExceptionUtils.rootCause(error) instanceof StalledDownloadException) {
       LOG.warn(
           "Fast sync was unable to download the world state. Retrying with a new pivot block.");
@@ -151,7 +150,8 @@ public class FastSyncDownloader<C> {
     // after the stop method had called cancel.
     synchronized (this) {
       if (!running.get()) {
-        return completedExceptionally(new CancellationException("FastSyncDownloader stopped"));
+        return CompletableFuture.failedFuture(
+            new CancellationException("FastSyncDownloader stopped"));
       }
       final CompletableFuture<Void> worldStateFuture =
           worldStateDownloader.run(currentState.getPivotBlockHeader().get());

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/fastsync/PivotBlockConfirmer.java

@@ -158,7 +158,7 @@ class PivotBlockConfirmer<C> {
   private CompletableFuture<BlockHeader> executePivotQuery(final long blockNumber) {
     if (isCancelled.get() || result.isDone()) {
       // Stop loop if this task is done
-      return FutureUtils.completedExceptionally(new CancellationException());
+      return CompletableFuture.failedFuture(new CancellationException());
     }
 
     final Optional<RetryingGetHeaderFromPeerByNumberTask> query = createPivotQuery(blockNumber);

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/CheckpointRangeSourceTest.java

@@ -19,7 +19,6 @@ import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static java.util.concurrent.CompletableFuture.completedFuture;
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.hyperledger.besu.util.FutureUtils.completedExceptionally;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
@@ -95,7 +94,7 @@ public class CheckpointRangeSourceTest {
   public void shouldNotHaveNextWhenNoMoreCheckpointsAvailableAndRetryLimitReached() {
     when(syncTargetChecker.shouldContinueDownloadingFromSyncTarget(any(), any())).thenReturn(true);
     when(checkpointFetcher.getNextCheckpointHeaders(peer, commonAncestor))
-        .thenReturn(completedExceptionally(new TimeoutException()));
+        .thenReturn(CompletableFuture.failedFuture(new TimeoutException()));
 
     for (int i = 1; i <= CHECKPOINT_TIMEOUTS_PERMITTED; i++) {
       assertThat(source).hasNext();
@@ -140,7 +139,7 @@ public class CheckpointRangeSourceTest {
   public void shouldDelayBeforeRetryingRequestForCheckpointHeadersAfterFailure() {
     when(syncTargetChecker.shouldContinueDownloadingFromSyncTarget(any(), any())).thenReturn(true);
     when(checkpointFetcher.getNextCheckpointHeaders(peer, commonAncestor))
-        .thenReturn(completedExceptionally(new RuntimeException("Nope")));
+        .thenReturn(CompletableFuture.failedFuture(new RuntimeException("Nope")));
 
     assertThat(source.next()).isNull();
     verify(checkpointFetcher).getNextCheckpointHeaders(peer, commonAncestor);
@@ -151,10 +150,10 @@ public class CheckpointRangeSourceTest {
   public void shouldResetCheckpointFailureCountWhenMoreCheckpointsReceived() {
     when(syncTargetChecker.shouldContinueDownloadingFromSyncTarget(any(), any())).thenReturn(true);
     when(checkpointFetcher.getNextCheckpointHeaders(any(), any()))
-        .thenReturn(completedExceptionally(new TimeoutException()))
-        .thenReturn(completedExceptionally(new TimeoutException()))
+        .thenReturn(CompletableFuture.failedFuture(new TimeoutException()))
+        .thenReturn(CompletableFuture.failedFuture(new TimeoutException()))
         .thenReturn(completedFuture(singletonList(header(15))))
-        .thenReturn(completedExceptionally(new TimeoutException()));
+        .thenReturn(CompletableFuture.failedFuture(new TimeoutException()));
 
     assertThat(source.next()).isNull(); // Fail
     assertThat(source.next()).isNull(); // Fail
@@ -234,7 +233,7 @@ public class CheckpointRangeSourceTest {
   @Test
   public void shouldSendNewRequestIfRequestForHeadersFails() {
     when(checkpointFetcher.getNextCheckpointHeaders(peer, commonAncestor))
-        .thenReturn(completedExceptionally(new NoAvailablePeersException()))
+        .thenReturn(CompletableFuture.failedFuture(new NoAvailablePeersException()))
         .thenReturn(completedFuture(asList(header(15), header(20))));
 
     // Returns null when the first request fails

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/fastsync/FastSyncDownloaderTest.java

@@ -132,7 +132,8 @@ public class FastSyncDownloaderTest {
   @Test
   public void shouldAbortIfWaitForSuitablePeersFails() {
     when(fastSyncActions.waitForSuitablePeers(FastSyncState.EMPTY_SYNC_STATE))
-        .thenReturn(completedExceptionally(new FastSyncException(FastSyncError.UNEXPECTED_ERROR)));
+        .thenReturn(
+            CompletableFuture.failedFuture(new FastSyncException(FastSyncError.UNEXPECTED_ERROR)));
 
     final CompletableFuture<FastSyncState> result = downloader.start();
 
@@ -483,12 +484,6 @@ public class FastSyncDownloaderTest {
     Assertions.assertThat(downloader.calculateTrailingPeerRequirements()).isEmpty();
   }
 
-  private <T> CompletableFuture<T> completedExceptionally(final Throwable error) {
-    final CompletableFuture<T> result = new CompletableFuture<>();
-    result.completeExceptionally(error);
-    return result;
-  }
-
   private <T> void assertCompletedExceptionally(
       final CompletableFuture<T> future, final FastSyncError expectedError) {
     assertThat(future).isCompletedExceptionally();

ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/rlpx/RlpxAgent.java

@@ -37,7 +37,6 @@ import org.hyperledger.besu.ethereum.p2p.rlpx.wire.messages.DisconnectMessage.Di
 import org.hyperledger.besu.metrics.BesuMetricCategory;
 import org.hyperledger.besu.plugin.services.MetricsSystem;
 import org.hyperledger.besu.plugin.services.metrics.Counter;
-import org.hyperledger.besu.util.FutureUtils;
 import org.hyperledger.besu.util.Subscribers;
 
 import java.util.ArrayList;
@@ -118,7 +117,7 @@ public class RlpxAgent {
 
   public CompletableFuture<Integer> start() {
     if (!started.compareAndSet(false, true)) {
-      return FutureUtils.completedExceptionally(
+      return CompletableFuture.failedFuture(
           new IllegalStateException(
               "Unable to start an already started " + getClass().getSimpleName()));
     }
@@ -141,7 +140,7 @@ public class RlpxAgent {
 
   public CompletableFuture<Void> stop() {
     if (!started.get() || !stopped.compareAndSet(false, true)) {
-      return FutureUtils.completedExceptionally(
+      return CompletableFuture.failedFuture(
           new IllegalStateException("Illegal attempt to stop " + getClass().getSimpleName()));
     }
 
@@ -196,7 +195,7 @@ public class RlpxAgent {
   public CompletableFuture<PeerConnection> connect(final Peer peer) {
     // Check if we're ready to establish connections
     if (!localNode.isReady()) {
-      return FutureUtils.completedExceptionally(
+      return CompletableFuture.failedFuture(
           new IllegalStateException(
               "Cannot connect before "
                   + this.getClass().getSimpleName()
@@ -208,7 +207,7 @@ public class RlpxAgent {
       final String errorMsg =
           "Attempt to connect to peer with no listening port: " + enode.toString();
       LOG.warn(errorMsg);
-      return FutureUtils.completedExceptionally((new IllegalArgumentException(errorMsg)));
+      return CompletableFuture.failedFuture((new IllegalArgumentException(errorMsg)));
     }
 
     // Shortcut checks if we're already connected
@@ -223,12 +222,11 @@ public class RlpxAgent {
               + maxConnections
               + "). Cannot connect to peer: "
               + peer;
-      return FutureUtils.completedExceptionally(new IllegalStateException(errorMsg));
+      return CompletableFuture.failedFuture(new IllegalStateException(errorMsg));
     }
     // Check permissions
     if (!peerPermissions.allowNewOutboundConnectionTo(peer)) {
-      return FutureUtils.completedExceptionally(
-          peerPermissions.newOutboundConnectionException(peer));
+      return CompletableFuture.failedFuture(peerPermissions.newOutboundConnectionException(peer));
     }
 
     // Initiate connection or return existing connection

util/src/main/java/org/hyperledger/besu/util/FutureUtils.java

@@ -24,19 +24,6 @@ import java.util.function.Supplier;
 
 public class FutureUtils {
 
-  /**
-   * Creates a {@link CompletableFuture} that is exceptionally completed by <code>error</code>.
-   *
-   * @param error the error to exceptionally complete the future with
-   * @param <T> the type of CompletableFuture
-   * @return a CompletableFuture exceptionally completed by <code>error</code>.
-   */
-  public static <T> CompletableFuture<T> completedExceptionally(final Throwable error) {
-    final CompletableFuture<T> future = new CompletableFuture<>();
-    future.completeExceptionally(error);
-    return future;
-  }
-
   /**
    * Returns a new CompletionStage that, when the provided stage completes exceptionally, is
    * executed with the provided stage's exception as the argument to the supplied function.

util/src/test/java/org/hyperledger/besu/util/FutureUtilsTest.java

@@ -37,7 +37,7 @@ public class FutureUtilsTest {
 
   @Test
   public void shouldCreateExceptionallyCompletedFuture() {
-    final CompletableFuture<Void> future = FutureUtils.completedExceptionally(ERROR);
+    final CompletableFuture<Void> future = CompletableFuture.failedFuture(ERROR);
     assertCompletedExceptionally(future, ERROR);
   }