Red Hat Application Server, Руководство пользователя

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Chapter 8. Developing Entity Beans 83
8.4.1. Primary Key Class Example
public class AccountBeanPK implements java.io.Serializable {
public int accno;
public AccountBeanPK(int accno) { this.accno = accno; }
public AccountBeanPK() { }
public int hashcode() { return accno; }
public boolean equals(Object other) {
...
}
}
8.4.1.1. Special Case: Automatic Generation of Primary Keys Field
There are two ways to manage automatic primary keys with JOnAS. The first method is closer to the
EJB specification (that is, an automatic PK is a hidden field, the type of which is not even known
by the application). In the second method, the idea is to declare a typical PK CMP field of the type
java.lang.Integer
as
automatic
. These two cases are described below.
8.4.1.1.1. Method 1: Standard Automatic Primary Keys (from JOnAS 4.0.0)
In this case, an automatic PK is a hidden field, the type of which is not known by the application.
All that is necessary is to stipulate in the standard deployment descriptor that this EJB has an auto-
matic PK; you do this by specifying
java.lang.Object
as primkey-class. The primary key will be
completely hidden from the application (no CMP field, no getter/setter method). This is valid for both
CMP 2.x and CMP1 entity beans. The container will create an internal CMP field and generate its
value when the Entity Bean is created.
8.4.1.1.1.1. Method 1 Example:
Standard deployment descriptor:
&
entity
'
...
&
ejb-name
'
AddressEJB
&
/ejb-name
'
&
local-home
'
com.titan.address.AddressHomeLocal
&
/local-home
'
&
local
'
com.titan.address.AddressLocal
&
/local
'
&
ejb-class
'
com.titan.address.AddressBean
&
/ejb-class
'
&
persistence-type
'
Container
&
/persistence-type
'
&
prim-key-class
'
java.lang.Object
&
/prim-key-class
'
&
reentrant
'
False
&
/reentrant
'
&
cmp-version
'
2.x
&
/cmp-version
'
&
abstract-schema-name
'
Cmp2_Address
&
/abstract-schema-name
'
&
cmp-field
'
&
field-name
'
street
&
/field-name
'
&
/cmp-field
'
&
cmp-field
'
&
field-name
'
city
&
/field-name
'
&
/cmp-field
'
&
cmp-field
'
&
field-name
'
state
&
/field-name
'
&
/cmp-field
'
&
cmp-field
'
&
field-name
'
zip
&
/field-name
'
&
/cmp-field
'
Address Bean Class extract:
// Primary key is not explicitly initialized during ejbCreate method
// No cmp field corresponds to the primary key
public Integer ejbCreateAddress(String street, String city,
String state, String zip ) throws javax.ejb.CreateException {
setStreet(street);
setCity(city);
setState(state);
setZip(zip);