Writing a simple Spring example using the Play! Framework

Question

I'm trying to set up the Spring 1.0.1 module to work with Play! 1.2.1.

Firstly I added the Spring module to the dependencies.yml:

- play -> spring 1.0.1

Then I added the following as per the documentation in the application.conf:

play.spring.component-scan=true

Then I ran the following to download the dependencies and update my IntelliJ configuration:

play deps --sync
play idealize

Now when I go back to IntelliJ, I can see that spring-1.0.1 has been added to my list of project modules which looks correct. However, if I look at the dependencies for my project it doesn't have the jars located in the spring-1.0.1/lib directory. If I try and annotate one of my classes with @Component, it cannot find it. However, if I manually add spring-1.0.1/lib as a project dependency it finds @Component just fine. Am I suppose to run something else to get my IntelliJ project to recognize the spring libraries found in the module?

The second part of my question relates to wiring up a simple example and writing a test for it.

So let's say I have a Job class like this:

@Component
@Every("10min")
public class MyJob extends Job {
    private @Inject Printer printer;

    @Override
    public void doJob() throws Exception {
        printer.print();
    }
}

And the Printer class looks like this:

@Component
public class Printer {
    public void print() {
        System.out.println("foo");
    }
}

Firstly, does the annotating look correct? And secondly, how would I go about writing a test that would call MyJob.doJob() but inject a different Printer that would print "bar" instead of "foo"?

Update: As mentioned by Aaron, I changed the @Inject to be @Autowired. In my test class, I have something like this:

@Test
public void testSomething() {
    MyJob job = play.modules.spring.Spring.getBeanOfType(MyJob.class);
    job.doJob();
    ...
}

It fails on that getBeanOfType statement with the following:

play.modules.spring.SpringException
at play.modules.spring.Spring.getBean(Spring.java:11)
at com.testing.JobTest.testSomething(MyJob.java:20)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at play.test.PlayJUnitRunner$StartPlay$1$1$1.execute(PlayJUnitRunner.java:73)
at play.Invoker$Invocation.run(Invoker.java:265)
at play.Invoker.invokeInThread(Invoker.java:67)
at play.test.PlayJUnitRunner$StartPlay$1$1.evaluate(PlayJUnitRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at play.test.PlayJUnitRunner.run(PlayJUnitRunner.java:48)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:60)

Update 2: Okay I've actually gotten further now. It seems as though even though I am doing component scanning, the Spring module still requires an application-context.xml in the conf/ directory (even though it defines no beans).

Now I just need to sort out how to inject a different version of the Printer object that spits out "bar" instead of "foo".

Update 3: I have replaced using @Autowired with @Resource(name="printer") and I have annotated my production printer with @Component("printer") and renamed it to RealPrinter and provided an interface:

@Component("printer")
public class RealPrinter implements Printer {
    public void print() {
        System.out.println("foo");
    }
}

If I have just the above Printer, the injection works fine. Now if I create a TestPrinter, I need Play's Spring Module to realize that I want to use the TestPrinter and not the RealPrinter when I'm executing a test class.

@Component("printer")
public class TestPrinter implements Printer {
    public void print() {
        System.out.println("bar");
    }
}

However, because I have two components qualified with the name "printer", Play's Spring Module throws the following exception:

play.exceptions.UnexpectedException: Unexpected Error
at play.Play.start(Play.java:491)
at play.test.PlayJUnitRunner.<init>(PlayJUnitRunner.java:31)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:31)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:24)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:29)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:24)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:66)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:192)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:60)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115)
Caused by: java.lang.IllegalStateException: Annotation-specified bean name 'printer' for bean class [com.testing.job.RealPrinter] conflicts with existing, non-compatible bean definition of same name and class [com.testing.job.TestPrinter]
at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.checkCandidate(ClassPathBeanDefinitionScanner.java:267)
at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:208)
at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.scan(ClassPathBeanDefinitionScanner.java:180)
at play.modules.spring.SpringPlugin.onApplicationStart(SpringPlugin.java:98)
at play.plugins.PluginCollection.onApplicationStart(PluginCollection.java:408)
at play.Play.start(Play.java:463)
... 19 more

As you can see, the cause of the exception is that there are now two Printers with the same name.

digiarnie digiarnie · Accepted Answer · 2011-06-01T02:17:02

Okay I have come up with a solution that works for me. So, to write a test that injects a mock/test version of a bean, I did the following:

@Test
public void testSomething() {
    GenericApplicationContext context = SpringPlugin.applicationContext;
    GenericBeanDefinition definition = new GenericBeanDefinition();
    definition.setBeanClass(TestPrinter.class);
    definition.setAutowireCandidate(true);
    context.registerBeanDefinition("printer", definition);

    MyJob job = new MyJob();
    job.doJob();
}

Then I had to change MyJob to be the root "injector" of things it needs:

public class MyJob extends Job {
    public void doJob() throws Exception {
        Printer printer = Spring.getBeanOfType(Printer.class);
        printer.print();
    }
}

The TestPrinter no longer needs to be annotated with @Component as the test method is programatically registering the test printer bean and thus overriding the production printer bean.

So executing the testSomething() method will result in "bar" being printed out. If I remove the registerBeanDefinition stuff, it will result in the production "foo" message being printed out.

I'm not exactly sure if this is the tidiest way of injecting test stuff using Play's Spring module, but at least I am able to do what I want now.

Writing a simple Spring example using the Play! Framework

2 Answers