content/custom-injection.mdtext

Title: Custom Injection
# Overview

As noted in the [Injection of env-entry Example](injection-of-env-entry-example.html)
, the EJB 3.0 supported env-entry types are fairly limited.  Also the use
of several <env-entry> tags in an ejb-jar.xml can get a bit verbose.

OpenEJB does not restrict you to just these data types or require you to
use an ejb-jar.xml to declare them.

 - `@Resource` can be used on any type for which there is
`java.beans.PropertyEditor`
 - You may `install your own` PropertyEditors and package them with your
app.
 - Java Generics are supported (e.g. List<URI> myURIs)
 - You may use a `META-INF/env-entries.properties` file as an alternative
to an ejb-jar.xml

See [Built-in Type Converters](built-in-type-converters.html)
for a full list of supported env-entry types.

The source for this example is the "custom-injection" directory located in
the [openejb-examples.zip](downloads.html)
available on the [download page](http://tomee.apache.org/downloads.html).

<a name="CustomInjection-TheCode"></a>
# The Code

<a name="CustomInjection-BeanClass"></a>
## Bean Class

    @Stateless
    public class Stratocaster {
    
        @Resource(name = "pickups")
        private List<Pickup> pickups;
    
        @Resource(name = "style")
        private Style style;
    
        @Resource(name = "dateCreated")
        private Date dateCreated;
    
        @Resource(name = "guitarStringGuages")
        private Map<String, Float> guitarStringGuages;
    
        @Resource(name = "certificateOfAuthenticity")
        private File certificateOfAuthenticity;
    
        public Date getDateCreated() {
            return dateCreated;
        }
    
        /**
         * Gets the guage of the electric guitar strings
         * used in this guitar.
         *
         * @param string
         * @return
         */
        public float getStringGuage(String string) {
            return guitarStringGuages.get(string);
        }
    
        public List<Pickup> getPickups() {
            return pickups;
        }
    
        public Style getStyle() {
            return style;
        }
    
        public File getCertificateOfAuthenticity() {
            return certificateOfAuthenticity;
        }
    }

<a name="CustomInjection-TheMETA-INF/env-entries.propertiesfile"></a>
## The META-INF/env-entries.properties file

    guitarStringGuages=E1=0.052\nA=0.042\nD=0.030\nG=0.017\nB=0.013\nE=0.010
    certificateOfAuthenticity=/tmp/strat-certificate.txt
    dateCreated=1962-03-01
    pickups=S,S,S
    style=VINTAGE

<a name="CustomInjection-TheCustomTypeandEditor"></a>
## The Custom Type and Editor

Support for java.lang.Enum types is already built-in, but we've decided
we'd like to allow abbreviated versions of the enum constants to be usable.
 We do this by creating a custom PropertyEditor for our Pickup enum like
so:

    public class PickupEditor extends java.beans.PropertyEditorSupport {
        public void setAsText(String text) throws IllegalArgumentException {
            text = text.trim();
    
            if (text.equalsIgnoreCase("H")) setValue(Pickup.HUMBUCKER);
            else if (text.equalsIgnoreCase("S")) setValue(Pickup.SINGLE_COIL);
            else throw new IllegalStateException("H and S are the only supported Pickup aliases");
        }
    }

We cleverly install this PropertyEditor in a static block in the Pickup
class that will be executed should someone actually reference the Pickup
type.

    public enum Pickup {
    
        HUMBUCKER,
        SINGLE_COIL;
    
        // Here's the little magic where we register the PickupEditor
        // which knows how to create this object from a string.
        // You can add any of your own Property Editors in the same way.
        static {
            PropertyEditorManager.registerEditor(Pickup.class, PickupEditor.class);
        }
    }

<a name="CustomInjection-TestCase"></a>
# Test Case

    public class StratocasterTest extends TestCase {
    
        @EJB
        private Stratocaster strat;
    
        public void test() throws Exception {
            EJBContainer.createEJBContainer().getContext().bind("inject", this);
    
            Date date = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.US).parse("Mar 1, 1962");
            assertEquals("Strat.getDateCreated()", date, strat.getDateCreated());
    
            List<Pickup> pickups = asList(Pickup.SINGLE_COIL, Pickup.SINGLE_COIL, Pickup.SINGLE_COIL);
            assertEquals("Strat.getPickups()", pickups, strat.getPickups());
    
            assertEquals("Strat.getStyle()", Style.VINTAGE, strat.getStyle());
    
            assertEquals("Strat.getStringGuage(\"E1\")", 0.052F, strat.getStringGuage("E1"));
            assertEquals("Strat.getStringGuage(\"A\")", 0.042F, strat.getStringGuage("A"));
            assertEquals("Strat.getStringGuage(\"D\")", 0.030F, strat.getStringGuage("D"));
            assertEquals("Strat.getStringGuage(\"G\")", 0.017F, strat.getStringGuage("G"));
            assertEquals("Strat.getStringGuage(\"B\")", 0.013F, strat.getStringGuage("B"));
            assertEquals("Strat.getStringGuage(\"E\")", 0.010F, strat.getStringGuage("E"));
    
            File file = new File("/tmp/strat-certificate.txt");
            assertEquals("Strat.getCertificateOfAuthenticity()", file,strat.getCertificateOfAuthenticity());
    
    
        }
    }

<a name="CustomInjection-Runningit"></a>
# Running it

Running the example is fairly simple.  In the "custom-injection" directory of the [examples zip](openejb:download.html), just run:

> $ mvn clean install

Which should create output like the following.


    -------------------------------------------------------
     T E S T S
    -------------------------------------------------------
    Running org.superbiz.enventries.StratocasterTest
    Apache OpenEJB 3.1-SNAPSHOT    build: 20080409-12:05
    http://tomee.apache.org/
    INFO - openejb.home = /Users/dblevins/work/openejb3/examples/custom-injection
    INFO - openejb.base = /Users/dblevins/work/openejb3/examples/custom-injection
    INFO - Configuring Service(id=Default Security Service, type=SecurityService, provider-id=Default Security Service)
    INFO - Configuring Service(id=Default Transaction Manager, type=TransactionManager, provider-id=Default Transaction Manager)
    INFO - Configuring Service(id=Default JDK 1.3 ProxyFactory, type=ProxyFactory, provider-id=Default JDK 1.3 ProxyFactory)
    INFO - Found EjbModule in classpath: /Users/dblevins/work/openejb3/examples/custom-injection/target/classes
    INFO - Configuring app: /Users/dblevins/work/openejb3/examples/custom-injection/target/classes
    INFO - Configuring Service(id=Default Stateless Container, type=Container, provider-id=Default Stateless Container)
    INFO - Auto-creating a container for bean StratocasterImpl: Container(type=STATELESS, id=Default Stateless Container)
    INFO - Loaded Module: /Users/dblevins/work/openejb3/examples/custom-injection/target/classes
    INFO - Assembling app: /Users/dblevins/work/openejb3/examples/custom-injection/target/classes
    INFO - Jndi(name=StratocasterImplLocal) --> Ejb(deployment-id=StratocasterImpl)
    INFO - Created Ejb(deployment-id=StratocasterImpl, ejb-name=StratocasterImpl, container=Default Stateless Container)
    INFO - Deployed Application(path=/Users/dblevins/work/openejb3/examples/custom-injection/target/classes)
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.705 sec
    
    Results :
    
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0