Author: dblevins
Date: Thu Jul 5 18:16:44 2012
New Revision: 1357783
URL: http://svn.apache.org/viewvc?rev=1357783&view=rev
Log:
Filled in description of CMP2 and how it works in OpenEJB
Modified:
openejb/trunk/openejb/examples/simple-cmp2/README.md
Modified: openejb/trunk/openejb/examples/simple-cmp2/README.md
URL:
http://svn.apache.org/viewvc/openejb/trunk/openejb/examples/simple-cmp2/README.md?rev=1357783&r1=1357782&r2=1357783&view=diff
==============================================================================
--- openejb/trunk/openejb/examples/simple-cmp2/README.md (original)
+++ openejb/trunk/openejb/examples/simple-cmp2/README.md Thu Jul 5 18:16:44
2012
@@ -1,33 +1,48 @@
-Title: Simple Cmp2
+Title: EJB 2.1 CMP EntityBeans (CMP2)
-*Help us document this example! Click the blue pencil icon in the upper right
to edit this page.*
-## Movie
- package org.superbiz.cmp2;
-
- /**
- * @version $Revision$ $Date$
- */
- public interface Movie extends javax.ejb.EJBLocalObject {
- java.lang.Integer getId();
-
- void setId(java.lang.Integer id);
-
- String getDirector();
-
- void setDirector(String director);
-
- String getTitle();
-
- void setTitle(String title);
-
- int getYear();
-
- void setYear(int year);
- }
+OpenEJB, the EJB Container for TomEE and Geronimo, does support all of EJB
1.1 to 3.1, including CMP2.
-## MovieBean
+The CMP2 implementation is actually done by adapting the CMP2 bean into a JPA
Entity dynamically at deploy time.
+
+Appropriate subclasses, a JPA persistence.xml file and a mapping.xml file are
generated at deployment
+time for the CMP2 EntityBeans and all the Entities will be then run on
OpenJPA. This innovative code
+has been used as the sole CMP2 implementation in Geronimo for its J2EE 1.4,
JavaEE 5 and JavaEE 6 certifications.
+
+The persistence.xml and mapping.xml files generated at deploy time can be
saved to disk and included
+in the application, allowing you to:
+
+ - gain finer control over persistence options
+ - slowly convert individual entities from CMP2 to JPA
+
+Let's see an example.
+
+# Movies application
+
+The following is a basic EJB 2.1 application consisting of one CMP2 Entity.
For those that are reading this example
+out of curiosity and are not familiar with CMP2 or EJB 2.x, each CMP2 Entity
is composed of two parts
+
+ - **A Home interface** which has data access methods like "find", "create",
and "remove". This is essentially
+ what people use `@Stateless` beans for today, but with difference that you
do not need to supply
+ the implementation of the interface -- the container will generate one for
you. This is partly what inspired
+ the creation of the OpenEJB-specific [Dynamic
DAO](../dynamic-dao-implementation/README.html) feature.
+
+ - **An abstract EntityBean class** which declares the persistent "properties"
of the entity without actually
+declaring any fields. It is the container's job to implement the actual
methods and create the appropriate
+fields. OpenEJB will implement this bean as a JPA `@Entity` bean.
+
+As such a CMP2 EntityBean is really just the description of a persistent
object and the description of a
+data-access object. There is no actual code to write.
+
+The majority of work in CMP2 is done in the xml:
+
+ - **ejb-jar.xml** mapping information, which describes the persistent
properties of the entity and the queries
+ for all *Home* find, create and remove methods. This information will be
converted by OpenEJB into
+ a JPA mapping.xml file. All queries in the cmp2 part of the ejb-jar.xml are
converted
+ into named queries in JPA and generally everything is converted to its JPA
equivalent.
+
+## CMP2 EntityBean, MovieBean
package org.superbiz.cmp2;
@@ -63,7 +78,7 @@ Title: Simple Cmp2
}
-## Movies
+## CMP2 Home interface, Movies
package org.superbiz.cmp2;
@@ -84,7 +99,7 @@ Title: Simple Cmp2
Collection<Movie> findByDirector(String director) throws
FinderException;
}
-## ejb-jar.xml
+## CMP2 mapping in ejb-jar.xml
<ejb-jar>
<enterprise-beans>
@@ -230,4 +245,4 @@ Title: Simple Cmp2
Results :
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
-
+
\ No newline at end of file
