[Plugin API] - Simplify plugin transaction selector interface to return object instead of list

ethereum/blockcreation/src/main/java/org/hyperledger/besu/ethereum/blockcreation/txselection/BlockTransactionSelector.java

@@ -18,6 +18,7 @@
 import org.hyperledger.besu.datatypes.Wei;
 import org.hyperledger.besu.ethereum.GasLimitCalculator;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.AbstractTransactionSelector;
+import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.AllAcceptingTransactionSelector;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.BlobPriceTransactionSelector;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.BlockSizeTransactionSelector;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.PriceTransactionSelector;
@@ -73,6 +74,7 @@
  */
 public class BlockTransactionSelector {
   private static final Logger LOG = LoggerFactory.getLogger(BlockTransactionSelector.class);
+
   private final Supplier<Boolean> isCancelled;
   private final MainnetTransactionProcessor transactionProcessor;
   private final Blockchain blockchain;
@@ -82,7 +84,7 @@ public class BlockTransactionSelector {
   private final TransactionSelectionResults transactionSelectionResults =
       new TransactionSelectionResults();
   private final List<AbstractTransactionSelector> transactionSelectors;
-  private final List<TransactionSelector> externalTransactionSelectors;
+  private final TransactionSelector externalTransactionSelector;
 
   public BlockTransactionSelector(
       final MainnetTransactionProcessor transactionProcessor,
@@ -117,8 +119,10 @@ public BlockTransactionSelector(
             miningBeneficiary,
             transactionPool);
     transactionSelectors = createTransactionSelectors(blockSelectionContext);
-    externalTransactionSelectors =
-        transactionSelectorFactory.map(TransactionSelectorFactory::create).orElse(List.of());
+    externalTransactionSelector =
+        transactionSelectorFactory
+            .map(TransactionSelectorFactory::create)
+            .orElse(AllAcceptingTransactionSelector.INSTANCE);
   }
 
   /**
@@ -263,18 +267,7 @@ private TransactionSelectionResult evaluateTransactionPreProcessing(
         return result;
       }
     }
-
-    // Process the transaction through external selectors
-    for (var selector : externalTransactionSelectors) {
-      TransactionSelectionResult result =
-          selector.evaluateTransactionPreProcessing(pendingTransaction);
-      // If the transaction is not selected by any external selector, return the result
-      if (!result.equals(TransactionSelectionResult.SELECTED)) {
-        return result;
-      }
-    }
-    // If the transaction is selected by all selectors, return SELECTED
-    return TransactionSelectionResult.SELECTED;
+    return externalTransactionSelector.evaluateTransactionPreProcessing(pendingTransaction);
   }
 
   /**
@@ -301,19 +294,8 @@ private TransactionSelectionResult evaluateTransactionPostProcessing(
         return result;
       }
     }
-
-    // Process the transaction through external selectors
-    for (var selector : externalTransactionSelectors) {
-      TransactionSelectionResult result =
-          selector.evaluateTransactionPostProcessing(pendingTransaction, processingResult);
-      // If the transaction is not selected by any external selector, return the result
-      if (!result.equals(TransactionSelectionResult.SELECTED)) {
-        return result;
-      }
-    }
-
-    // If the transaction is selected by all selectors, return SELECTED
-    return TransactionSelectionResult.SELECTED;
+    return externalTransactionSelector.evaluateTransactionPostProcessing(
+        pendingTransaction, processingResult);
   }
 
   private List<AbstractTransactionSelector> createTransactionSelectors(

ethereum/blockcreation/src/main/java/org/hyperledger/besu/ethereum/blockcreation/txselection/selectors/AllAcceptingTransactionSelector.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright Hyperledger Besu Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.ethereum.blockcreation.txselection.selectors;
+
+import org.hyperledger.besu.datatypes.PendingTransaction;
+import org.hyperledger.besu.plugin.data.TransactionProcessingResult;
+import org.hyperledger.besu.plugin.data.TransactionSelectionResult;
+import org.hyperledger.besu.plugin.services.txselection.TransactionSelector;
+
+/** A TransactionSelector that unconditionally selects all transactions. */
+public class AllAcceptingTransactionSelector implements TransactionSelector {
+  public static final AllAcceptingTransactionSelector INSTANCE =
+      new AllAcceptingTransactionSelector();
+
+  private AllAcceptingTransactionSelector() {}
+
+  /**
+   * Always selects the transaction in the pre-processing stage.
+   *
+   * @param pendingTransaction The transaction to be evaluated.
+   * @return Always SELECTED.
+   */
+  @Override
+  public TransactionSelectionResult evaluateTransactionPreProcessing(
+      final PendingTransaction pendingTransaction) {
+    return TransactionSelectionResult.SELECTED;
+  }
+
+  /**
+   * Always selects the transaction in the post-processing stage.
+   *
+   * @param pendingTransaction The transaction to be evaluated.
+   * @param processingResult The result of the transaction processing.
+   * @return Always SELECTED.
+   */
+  @Override
+  public TransactionSelectionResult evaluateTransactionPostProcessing(
+      final PendingTransaction pendingTransaction,
+      final TransactionProcessingResult processingResult) {
+    return TransactionSelectionResult.SELECTED;
+  }
+}

ethereum/blockcreation/src/test/java/org/hyperledger/besu/ethereum/blockcreation/AbstractBlockTransactionSelectorTest.java

@@ -554,26 +554,25 @@ public void transactionSelectionPluginShouldWork_PreProcessing() {
 
     final TransactionSelectorFactory transactionSelectorFactory =
         () ->
-            List.of(
-                new TransactionSelector() {
-                  @Override
-                  public TransactionSelectionResult evaluateTransactionPreProcessing(
-                      final PendingTransaction pendingTransaction) {
-                    if (pendingTransaction.getTransaction().equals(notSelectedTransient))
-                      return TransactionSelectionResult.invalidTransient("transient");
-                    if (pendingTransaction.getTransaction().equals(notSelectedInvalid))
-                      return TransactionSelectionResult.invalid("invalid");
-                    return TransactionSelectionResult.SELECTED;
-                  }
-
-                  @Override
-                  public TransactionSelectionResult evaluateTransactionPostProcessing(
-                      final PendingTransaction pendingTransaction,
-                      final org.hyperledger.besu.plugin.data.TransactionProcessingResult
-                          processingResult) {
-                    return TransactionSelectionResult.SELECTED;
-                  }
-                });
+            new TransactionSelector() {
+              @Override
+              public TransactionSelectionResult evaluateTransactionPreProcessing(
+                  final PendingTransaction pendingTransaction) {
+                if (pendingTransaction.getTransaction().equals(notSelectedTransient))
+                  return TransactionSelectionResult.invalidTransient("transient");
+                if (pendingTransaction.getTransaction().equals(notSelectedInvalid))
+                  return TransactionSelectionResult.invalid("invalid");
+                return TransactionSelectionResult.SELECTED;
+              }
+
+              @Override
+              public TransactionSelectionResult evaluateTransactionPostProcessing(
+                  final PendingTransaction pendingTransaction,
+                  final org.hyperledger.besu.plugin.data.TransactionProcessingResult
+                      processingResult) {
+                return TransactionSelectionResult.SELECTED;
+              }
+            };
 
     final Address miningBeneficiary = AddressHelpers.ofValue(1);
     final BlockTransactionSelector selector =
@@ -619,27 +618,25 @@ public void transactionSelectionPluginShouldWork_PostProcessing() {
 
     final TransactionSelectorFactory transactionSelectorFactory =
         () ->
-            List.of(
-                new TransactionSelector() {
-                  @Override
-                  public TransactionSelectionResult evaluateTransactionPreProcessing(
-                      final PendingTransaction pendingTransaction) {
-                    return TransactionSelectionResult.SELECTED;
-                  }
-
-                  @Override
-                  public TransactionSelectionResult evaluateTransactionPostProcessing(
-                      final PendingTransaction pendingTransaction,
-                      final org.hyperledger.besu.plugin.data.TransactionProcessingResult
-                          processingResult) {
-                    // the transaction with max gas +1 should fail
-                    if (processingResult.getEstimateGasUsedByTransaction()
-                        > maxGasUsedByTransaction) {
-                      return TransactionSelectionResult.invalidTransient("Invalid");
-                    }
-                    return TransactionSelectionResult.SELECTED;
-                  }
-                });
+            new TransactionSelector() {
+              @Override
+              public TransactionSelectionResult evaluateTransactionPreProcessing(
+                  final PendingTransaction pendingTransaction) {
+                return TransactionSelectionResult.SELECTED;
+              }
+
+              @Override
+              public TransactionSelectionResult evaluateTransactionPostProcessing(
+                  final PendingTransaction pendingTransaction,
+                  final org.hyperledger.besu.plugin.data.TransactionProcessingResult
+                      processingResult) {
+                // the transaction with max gas +1 should fail
+                if (processingResult.getEstimateGasUsedByTransaction() > maxGasUsedByTransaction) {
+                  return TransactionSelectionResult.invalidTransient("Invalid");
+                }
+                return TransactionSelectionResult.SELECTED;
+              }
+            };
 
     final Address miningBeneficiary = AddressHelpers.ofValue(1);
     final BlockTransactionSelector selector =

plugin-api/build.gradle

@@ -69,7 +69,7 @@ Calculated : ${currentHash}
 tasks.register('checkAPIChanges', FileStateChecker) {
   description = "Checks that the API for the Plugin-API project does not change without deliberate thought"
   files = sourceSets.main.allJava.files
-  knownHash = 'IPqcFdM1uy+ZDbcvzsKxMIrzhP9VoaSeanhBOLtbhfE='
+  knownHash = '8NVdDoCnMQiibEZUsZuemZU+wm3W1LPklcQkiKsriKs='
 }
 check.dependsOn('checkAPIChanges')
 

plugin-api/src/main/java/org/hyperledger/besu/plugin/services/txselection/TransactionSelectorFactory.java

@@ -17,16 +17,14 @@
 
 import org.hyperledger.besu.plugin.Unstable;
 
-import java.util.List;
-
 /** Interface for a factory that creates transaction selectors */
 @Unstable
 public interface TransactionSelectorFactory {
 
   /**
-   * Create a list of transaction selectors
+   * Create a transaction selector
    *
-   * @return the transaction selector list
+   * @return the transaction selector
    */
-  List<TransactionSelector> create();
+  TransactionSelector create();
 }