Remove CountDownLatch to simplify

Resolves #8

Author: gregturn

README.adoc

@@ -120,10 +120,20 @@ The first method defines the job and the second one defines a single step. Jobs
 
 In this job definition, you need an incrementer because jobs use a database to maintain execution state. You then list each step, of which this job has only one step. The job ends, and the Java API produces a perfectly configured job.
 
+The `listener()` method lets you hook into the engine and detect when the job is complete, triggering the verification of results.
+
 In the step definition, you define how much data to write at a time. In this case, it writes up to ten records at a time. Next, you configure the reader, processor, and writer using the injected bits from earlier. 
 
 NOTE: chunk() is prefixed `<Person,Person>` because it's a generic method. This represents the input and output types of each "chunk" of processing, and lines up with `ItemReader<Person>` and `ItemWriter<Person>`.
 
+`src/main/java/hello/JobCompletionNotificationListener.java`
+[source,java]
+----
+include::/complete/src/main/java/hello/JobCompletionNotificationListener.java[]
+----
+
+This code listens for when a job is `BatchStatus.COMPLETED`, and then uses `JdbcTemplate` to inspect the results.
+
 
 == Make the application executable
 

complete/src/main/java/hello/Application.java

@@ -1,36 +1,12 @@
 package hello;
 
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.util.List;
-import java.util.concurrent.CountDownLatch;
-
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.context.ApplicationContext;
-import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.jdbc.core.RowMapper;
 
 @SpringBootApplication
 public class Application {
 
     public static void main(String[] args) throws Exception {
-        ApplicationContext ctx = SpringApplication.run(Application.class, args);
-
-        CountDownLatch countDownLatch = ctx.getBean(CountDownLatch.class);
-
-        countDownLatch.await();
-
-        List<Person> results = ctx.getBean(JdbcTemplate.class).query("SELECT first_name, last_name FROM people", new RowMapper<Person>() {
-            @Override
-            public Person mapRow(ResultSet rs, int row) throws SQLException {
-                return new Person(rs.getString(1), rs.getString(2));
-            }
-        });
-
-        for (Person person : results) {
-            System.out.println("Found <" + person + "> in the database.");
-        }
-
+        SpringApplication.run(Application.class, args);
     }
 }

complete/src/main/java/hello/BatchConfiguration.java

@@ -1,7 +1,5 @@
 package hello;
 
-import java.util.concurrent.CountDownLatch;
-
 import javax.sql.DataSource;
 
 import org.springframework.batch.core.Job;
@@ -29,16 +27,6 @@
 @EnableBatchProcessing
 public class BatchConfiguration {
 
-    @Bean
-    public CountDownLatch countDownLatch() {
-        return new CountDownLatch(1);
-    }
-
-    @Bean
-    public JobExecutionListener jobExecutionListener(CountDownLatch countDownLatch) {
-        return new JobCompletionNotificationListener(countDownLatch);
-    }
-
     // tag::readerwriterprocessor[]
     @Bean
     public ItemReader<Person> reader() {

complete/src/main/java/hello/JobCompletionNotificationListener.java

@@ -15,30 +15,52 @@
  */
 package hello;
 
-import java.util.concurrent.CountDownLatch;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.listener.JobExecutionListenerSupport;
-import org.springframework.util.Assert;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.RowMapper;
+import org.springframework.stereotype.Component;
 
 /**
  * @author Michael Minella
  */
+@Component
 public class JobCompletionNotificationListener extends JobExecutionListenerSupport {
 
-	private CountDownLatch countDownLatch;
+	private static final Logger log = LoggerFactory.getLogger(JobCompletionNotificationListener.class);
 
-	public JobCompletionNotificationListener(CountDownLatch countDownLatch) {
-		Assert.notNull(countDownLatch);
+	private final JdbcTemplate jdbcTemplate;
 
-		this.countDownLatch = countDownLatch;
+	@Autowired
+	public JobCompletionNotificationListener(JdbcTemplate jdbcTemplate) {
+		this.jdbcTemplate = jdbcTemplate;
 	}
 
 	@Override
 	public void afterJob(JobExecution jobExecution) {
 		if(jobExecution.getStatus() == BatchStatus.COMPLETED) {
-			countDownLatch.countDown();
+			log.info("!!! JOB FINISHED! Time to verify the results");
+
+			List<Person> results = jdbcTemplate.query("SELECT first_name, last_name FROM people", new RowMapper<Person>() {
+				@Override
+				public Person mapRow(ResultSet rs, int row) throws SQLException {
+					return new Person(rs.getString(1), rs.getString(2));
+				}
+			});
+
+			for (Person person : results) {
+				log.info("Found <" + person + "> in the database.");
+			}
+
 		}
 	}
 }

complete/src/main/java/hello/PersonItemProcessor.java

@@ -1,17 +1,22 @@
 package hello;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import org.springframework.batch.item.ItemProcessor;
 
 public class PersonItemProcessor implements ItemProcessor<Person, Person> {
 
+    private static final Logger log = LoggerFactory.getLogger(PersonItemProcessor.class);
+
     @Override
     public Person process(final Person person) throws Exception {
         final String firstName = person.getFirstName().toUpperCase();
         final String lastName = person.getLastName().toUpperCase();
 
         final Person transformedPerson = new Person(firstName, lastName);
 
-        System.out.println("Converting (" + person + ") into (" + transformedPerson + ")");
+        log.info("Converting (" + person + ") into (" + transformedPerson + ")");
 
         return transformedPerson;
     }