Support command as array of strings

setCommand now supports passing in an array of strings. When a single
string is supplied, it is tokenized by the Runtime#exec method. When an
array of strings is supplied, the array is supplied as is to the
Runtime#exec method in which case no tokenization takes place.

Resolves spring-projects#752

Author: Philippe Truche

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

@@ -46,7 +46,7 @@
  * so that the batch job does not hang forever if the external process hangs.
  *
  * Tasklet periodically checks for termination status (i.e.
- * {@link #setCommand(String)} finished its execution or
+ * {@link #setCommand(String...)} finished its execution or
  * {@link #setTimeout(long)} expired or job was interrupted). The check interval
  * is given by {@link #setTerminationCheckInterval(long)}.
  *
@@ -64,7 +64,7 @@ public class SystemCommandTasklet extends StepExecutionListenerSupport implement
 
 	protected static final Log logger = LogFactory.getLog(SystemCommandTasklet.class);
 
-	private String command;
+	private String[] cmdArray;
 
 	private String[] environmentParams = null;
 
@@ -100,8 +100,15 @@ public RepeatStatus execute(StepContribution contribution, ChunkContext chunkCon
 
 			@Override
 			public Integer call() throws Exception {
-				Process process = Runtime.getRuntime().exec(command, environmentParams, workingDirectory);
-				return process.waitFor();
+				if (cmdArray.length == 1) {
+					String command = cmdArray[0];
+					Process process = Runtime.getRuntime().exec(command, environmentParams, workingDirectory);
+					return process.waitFor();
+				} else {
+					Process process = Runtime.getRuntime().exec(cmdArray, environmentParams, workingDirectory);
+					return process.waitFor();
+				}
+
 			}
 
 		});
@@ -132,6 +139,7 @@ else if (System.currentTimeMillis() - t0 > timeout) {
 			}
 			else if (execution.isTerminateOnly()) {
 				systemCommandTask.cancel(interruptOnCancel);
+				String command = String.join(" ", cmdArray);
 				throw new JobInterruptedException("Job interrupted while executing system command '" + command + "'");
 			}
 			else if (stopped) {
@@ -143,10 +151,17 @@ else if (stopped) {
 	}
 
 	/**
-	 * @param command command to be executed in a separate system process
+	 * @param command command to be executed in a separate system process. Either a single command can be supplied
+	 *                to be tokenized with a space delimiter, or the command and its arguments are supplied as multiple
+	 *                strings that are not tokenized.
+	 * <p>
+	 * <p>Possible calls to setCommand:
+     *
+	 * <pre> {@code setCommand("myCommand myArg1 myArg2");}</pre>
+	 * <pre> {@code setCommand("myCommand", "myArg1", "myArg2 'args for myArg2'");}</pre>
 	 */
-	public void setCommand(String command) {
-		this.command = command;
+	public void setCommand(String... command) {
+		this.cmdArray = command ;
 	}
 
 	/**
@@ -174,7 +189,10 @@ public void setWorkingDirectory(String dir) {
 
 	@Override
 	public void afterPropertiesSet() throws Exception {
-		Assert.hasLength(command, "'command' property value is required");
+		Assert.notNull(cmdArray, "'cmdArray' property value is required with at least 1 element");
+		Assert.notEmpty(cmdArray, "'cmdArray' property value is required with at least 1 element");
+		Assert.noNullElements(cmdArray, "'cmdArray' property value is required with at least 1 element");
+		Assert.hasLength(cmdArray[0], "'cmdArray' property value is required with at least 1 element");
 		Assert.notNull(systemProcessExitCodeMapper, "SystemProcessExitCodeMapper must be set");
 		Assert.isTrue(timeout > 0, "timeout value must be greater than zero");
 		Assert.notNull(taskExecutor, "taskExecutor is required");

spring-batch-core/src/test/java/org/springframework/batch/core/step/tasklet/SystemCommandTaskletIntegrationTests.java

@@ -81,6 +81,20 @@ private void initializeTasklet() {
 		tasklet.setTaskExecutor(new SimpleAsyncTaskExecutor());
 	}
 
+	/*
+	 * Power usage scenario - successful execution of system command.
+	 */
+	@Test
+	public void testExecuteWithSeparateArgument() throws Exception {
+		tasklet.setCommand(getJavaCommand(), "--version");
+		tasklet.afterPropertiesSet();
+
+		log.info("Executing command: " + getJavaCommand() + " --version");
+		RepeatStatus exitStatus = tasklet.execute(stepExecution.createStepContribution(), null);
+
+		assertEquals(RepeatStatus.FINISHED, exitStatus);
+	}
+
 	/*
 	 * Regular usage scenario - successful execution of system command.
 	 */
@@ -199,6 +213,33 @@ public void testCommandNotSet() throws Exception {
 		catch (IllegalArgumentException e) {
 			// expected
 		}
+
+		tasklet.setCommand(new String[] {});
+		try {
+			tasklet.afterPropertiesSet();
+			fail();
+		}
+		catch (IllegalArgumentException e) {
+			// expected
+		}
+
+		tasklet.setCommand(new String[] { null });
+		try {
+			tasklet.afterPropertiesSet();
+			fail();
+		}
+		catch (IllegalArgumentException e) {
+			// expected
+		}
+
+		tasklet.setCommand(new String[] { "" });
+		try {
+			tasklet.afterPropertiesSet();
+			fail();
+		}
+		catch (IllegalArgumentException e) {
+			// expected
+		}
 	}
 
 	/*