Improve step execution polling and retrieval

Resolves #3790

---
Ported from c68da18 without the JSR related bits

spring-batch-core/src/main/java/org/springframework/batch/core/partition/support/RemoteStepExecutionAggregator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,12 @@
 
 package org.springframework.batch.core.partition.support;
 
-import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
+import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.core.explore.JobExplorer;
 import org.springframework.beans.factory.InitializingBean;
@@ -88,14 +91,16 @@ public void aggregate(StepExecution result, Collection<StepExecution> executions
 		if (executions == null) {
 			return;
 		}
-		Collection<StepExecution> updates = new ArrayList<>();
-		for (StepExecution stepExecution : executions) {
+		Set<Long> stepExecutionIds = executions.stream().map(stepExecution -> {
 			Long id = stepExecution.getId();
 			Assert.state(id != null, "StepExecution has null id. It must be saved first: " + stepExecution);
-			StepExecution update = jobExplorer.getStepExecution(stepExecution.getJobExecutionId(), id);
-			Assert.state(update != null, "Could not reload StepExecution from JobRepository: " + stepExecution);
-			updates.add(update);
-		}
+			return id;
+		}).collect(Collectors.toSet());
+		JobExecution jobExecution = jobExplorer.getJobExecution(result.getJobExecutionId());
+		Assert.state(jobExecution != null,
+				"Could not load JobExecution from JobRepository for id " + result.getJobExecutionId());
+		List<StepExecution> updates = jobExecution.getStepExecutions().stream()
+				.filter(stepExecution -> stepExecutionIds.contains(stepExecution.getId())).collect(Collectors.toList());
 		delegate.aggregate(result, updates);
 	}
 

spring-batch-integration/src/main/java/org/springframework/batch/integration/partition/MessageChannelPartitionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2022 the original author or authors.
+ * Copyright 2009-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,6 @@
 package org.springframework.batch.integration.partition;
 
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.Callable;
@@ -29,6 +28,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.Step;
 import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.core.explore.JobExplorer;
@@ -256,20 +256,13 @@ private Set<StepExecution> pollReplies(final StepExecution managerStepExecution,
 		Callable<Set<StepExecution>> callback = new Callable<Set<StepExecution>>() {
 			@Override
 			public Set<StepExecution> call() throws Exception {
-
-				for (Iterator<StepExecution> stepExecutionIterator = split.iterator(); stepExecutionIterator
-						.hasNext();) {
-					StepExecution curStepExecution = stepExecutionIterator.next();
-
-					if (!result.contains(curStepExecution)) {
-						StepExecution partitionStepExecution = jobExplorer
-								.getStepExecution(managerStepExecution.getJobExecutionId(), curStepExecution.getId());
-
-						if (!partitionStepExecution.getStatus().isRunning()) {
-							result.add(partitionStepExecution);
-						}
-					}
-				}
+				Set<Long> currentStepExecutionIds = split.stream().map(StepExecution::getId)
+						.collect(Collectors.toSet());
+				JobExecution jobExecution = jobExplorer.getJobExecution(managerStepExecution.getJobExecutionId());
+				jobExecution.getStepExecutions().stream()
+						.filter(stepExecution -> currentStepExecutionIds.contains(stepExecution.getId()))
+						.filter(stepExecution -> !result.contains(stepExecution))
+						.filter(stepExecution -> !stepExecution.getStatus().isRunning()).forEach(result::add);
 
 				if (logger.isDebugEnabled()) {
 					logger.debug(String.format("Currently waiting on %s partitions to finish", split.size()));

spring-batch-integration/src/test/java/org/springframework/batch/integration/partition/MessageChannelPartitionHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2022 the original author or authors.
+ * Copyright 2020-2023 the original author or authors.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 
 package org.springframework.batch.integration.partition;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -174,8 +175,12 @@ void testHandleWithJobRepositoryPolling() throws Exception {
 		stepExecutions.add(partition2);
 		stepExecutions.add(partition3);
 		when(stepExecutionSplitter.split(any(StepExecution.class), eq(1))).thenReturn(stepExecutions);
-		when(jobExplorer.getStepExecution(eq(5L), any(Long.class))).thenReturn(partition2, partition1, partition3,
-				partition3, partition3, partition3, partition4);
+		JobExecution runningJobExecution = new JobExecution(5L, new JobParameters());
+		runningJobExecution.addStepExecutions(Arrays.asList(partition2, partition1, partition3));
+		JobExecution completedJobExecution = new JobExecution(5L, new JobParameters());
+		completedJobExecution.addStepExecutions(Arrays.asList(partition2, partition1, partition4));
+		when(jobExplorer.getJobExecution(5L)).thenReturn(runningJobExecution, runningJobExecution, runningJobExecution,
+				completedJobExecution);
 
 		// set
 		messageChannelPartitionHandler.setMessagingOperations(operations);
@@ -220,7 +225,9 @@ void testHandleWithJobRepositoryPollingTimeout() throws Exception {
 		stepExecutions.add(partition2);
 		stepExecutions.add(partition3);
 		when(stepExecutionSplitter.split(any(StepExecution.class), eq(1))).thenReturn(stepExecutions);
-		when(jobExplorer.getStepExecution(eq(5L), any(Long.class))).thenReturn(partition2, partition1, partition3);
+		JobExecution runningJobExecution = new JobExecution(5L, new JobParameters());
+		runningJobExecution.addStepExecutions(Arrays.asList(partition2, partition1, partition3));
+		when(jobExplorer.getJobExecution(5L)).thenReturn(runningJobExecution);
 
 		// set
 		messageChannelPartitionHandler.setMessagingOperations(operations);