Add ability to stop any kind of step

Before this commit, it was only possible to
stop tasklet steps.

This commit introduces a new interface to be
implemented by any step that is able to handle
external stop signals.

Resolves #4965

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/launch/support/SimpleJobOperator.java

@@ -36,6 +36,7 @@
 import org.springframework.batch.core.job.parameters.JobParametersIncrementer;
 import org.springframework.batch.core.job.parameters.JobParametersInvalidException;
 import org.springframework.batch.core.step.Step;
+import org.springframework.batch.core.step.StoppableStep;
 import org.springframework.batch.core.step.StepExecution;
 import org.springframework.batch.core.job.UnexpectedJobExecutionException;
 import org.springframework.batch.core.configuration.JobRegistry;
@@ -351,6 +352,11 @@ public boolean stop(JobExecution jobExecution) throws JobExecutionNotRunningExce
 									StepSynchronizationManager.release();
 								}
 							}
+							if (step instanceof StoppableStep stoppableStep) {
+								StepSynchronizationManager.register(stepExecution);
+								stoppableStep.stop(stepExecution);
+								StepSynchronizationManager.release();
+							}
 						}
 						catch (NoSuchStepException e) {
 							logger.warn("Step not found", e);

spring-batch-core/src/main/java/org/springframework/batch/core/step/AbstractStep.java

@@ -63,7 +63,7 @@
  * @author Mahmoud Ben Hassine
  * @author Jinwoo Bae
  */
-public abstract class AbstractStep implements Step, InitializingBean, BeanNameAware {
+public abstract class AbstractStep implements StoppableStep, InitializingBean, BeanNameAware {
 
 	private static final Log logger = LogFactory.getLog(AbstractStep.class);
 

spring-batch-core/src/main/java/org/springframework/batch/core/step/StoppableStep.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2025-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.
+ */
+package org.springframework.batch.core.step;
+
+/**
+ * Extension of the {@link Step} interface to be implemented by steps that support being
+ * stopped.
+ *
+ * @author Mahmoud Ben Hassine
+ * @since 6.0
+ */
+public interface StoppableStep extends Step {
+
+	/**
+	 * Callback to signal the step to stop. The default implementation sets the
+	 * {@link StepExecution} to terminate only. Concrete implementations can override this
+	 * method to add custom stop logic.
+	 * @param stepExecution the current step execution
+	 */
+	default void stop(StepExecution stepExecution) {
+		stepExecution.setTerminateOnly();
+	}
+
+}