Add a getJobId convenience method to StepContext

Resolves BATCH-2769

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/StepContext.java

@@ -48,6 +48,7 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
+ * @author Nicolas Widart
  *
  */
 public class StepContext extends SynchronizedAttributeAccessor {
@@ -101,6 +102,19 @@ public class StepContext extends SynchronizedAttributeAccessor {
 		return stepExecution.getJobExecution().getJobInstance().getJobName();
 	}
 
+	/**
+	 * Convenient accessor for current job identifier.
+	 *
+	 * @return the job identifier of the enclosing {@link JobInstance}
+	 * associated with the current {@link StepExecution}
+	 */
+	public Long getJobId() {
+		Assert.state(stepExecution.getJobExecution() != null, "StepExecution does not have a JobExecution");
+		Assert.state(stepExecution.getJobExecution().getJobInstance() != null,
+				"StepExecution does not have a JobInstance");
+		return stepExecution.getJobExecution().getJobInstance().getId();
+	}
+
 	/**
 	 * Convenient accessor for System properties to make it easy to access them
 	 * from placeholder expressions.

spring-batch-core/src/test/java/org/springframework/batch/core/scope/context/StepContextTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2014 the original author or authors.
+ * Copyright 2006-2018 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.
@@ -37,6 +37,7 @@ import org.springframework.batch.item.ExecutionContext;
 
 /**
  * @author Dave Syer
+ * @author Nicolas Widart
  *
  */
 public class StepContextTests {
@@ -164,6 +165,11 @@ public class StepContextTests {
 		assertEquals("job", context.getJobName());
 	}
 
+	@Test
+	public void testJobId() throws Exception {
+		assertEquals(2L, (long)context.getJobId());
+	}
+
 	@Test
 	public void testStepExecutionContext() throws Exception {
 		ExecutionContext executionContext = stepExecution.getExecutionContext();