Add method getJobInstance in JobOperator

Issue #3930

Author: fmbenhassine

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2022 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.
@@ -30,13 +30,15 @@
 import org.springframework.batch.core.repository.JobExecutionAlreadyRunningException;
 import org.springframework.batch.core.repository.JobInstanceAlreadyCompleteException;
 import org.springframework.batch.core.repository.JobRestartException;
+import org.springframework.lang.Nullable;
 
 /**
  * Low level interface for inspecting and controlling jobs with access only to primitive
  * and collection types. Suitable for a command-line client (e.g. that launches a new
  * process for each operation), or a remote launcher like a JMX console.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  */
 public interface JobOperator {
@@ -65,6 +67,19 @@ public interface JobOperator {
 	 */
 	List<Long> getJobInstances(String jobName, int start, int count) throws NoSuchJobException;
 
+	/**
+	 * @param jobName {@link String} name of the job.
+	 * @param jobParameters {@link JobParameters} parameters for the job instance.
+	 * @return the {@link JobInstance} with the given name and parameters, or
+	 * {@code null}.
+	 *
+	 * @since 5.0
+	 */
+	@Nullable
+	default JobInstance getJobInstance(String jobName, JobParameters jobParameters) {
+		throw new UnsupportedOperationException();
+	}
+
 	/**
 	 * Get the id values of all the running {@link JobExecution JobExecutions} with the
 	 * given job name.

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

@@ -61,6 +61,7 @@
 import org.springframework.batch.core.step.tasklet.Tasklet;
 import org.springframework.batch.core.step.tasklet.TaskletStep;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.Assert;
 
@@ -198,6 +199,17 @@ public List<Long> getJobInstances(String jobName, int start, int count) throws N
 		return list;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 *
+	 * @see org.springframework.batch.core.launch.JobOperator#getJobInstance(String,
+	 * JobParameters)
+	 */
+	@Nullable
+	public JobInstance getJobInstance(String jobName, JobParameters jobParameters) {
+		return this.jobExplorer.getJobInstance(jobName, jobParameters);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 *

spring-batch-core/src/test/java/org/springframework/batch/core/launch/support/SimpleJobOperatorTests.java

@@ -272,6 +272,22 @@ void testGetLastInstancesNoSuchJob() {
 		assertThrows(NoSuchJobException.class, () -> jobOperator.getJobInstances("no-such-job", 0, 2));
 	}
 
+	@Test
+	public void testGetJobInstanceWithNameAndParameters() {
+		// given
+		String jobName = "job";
+		JobParameters jobParameters = new JobParameters();
+		JobInstance jobInstance = mock(JobInstance.class);
+
+		// when
+		when(this.jobExplorer.getJobInstance(jobName, jobParameters)).thenReturn(jobInstance);
+		JobInstance actualJobInstance = this.jobOperator.getJobInstance(jobName, jobParameters);
+
+		// then
+		verify(this.jobExplorer).getJobInstance(jobName, jobParameters);
+		assertEquals(jobInstance, actualJobInstance);
+	}
+
 	@Test
 	void testGetJobNames() {
 		Set<String> names = jobOperator.getJobNames();