asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13,
asp.net ean 13,

asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,

asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,

By default, the standard Struts base class is used; however, if a different base class is desired, the property struts.base.class can be overridden. This override could occur at many levels, depending on your needs, but typically it would be from a properties file (see Ant properties in chapter 3). You could even define a new base class from the command-line:

You can now use this domain identifier as a column type when creating a table:

Overriding a base class at build time is perhaps an extreme example of XDoclet s Ant property substitution, and use of a factory-like design pattern could certainly accomplish similar capabilities. The possibilities that open up with this feature are astounding code-generation with build-time control over switches and parameters. Note the use of <packageSubstitution> nested in <ejbdoclet> and within <strutsform>. By default, generated code gets placed in the same package as the original source code being processed. Code can be relocated to more meaningful packages, and their corresponding directories, by using <packageSubstitution>. For example, our sample entity bean is in package org.example.antbook.ejb. All code, except from <strutsform>, is generated into org.example.antbook.interfaces. The <strutsform>-generated code overrides the global package substitution and its code generates into package org.example.antbook.struts.

create table USERS ( ... USER_EMAIL EMAILADDRESS(255) not null, ... );

The (relatively minor) advantage of domains in SQL is the abstraction of common constraints into a single location. Domain constraints are always checked immediately when data is inserted and modified. To complete the previous example, you also have to write the stored function IS_EMAILADDRESS (you can find many regular expressions to do this on the Web). Adding the new domain in a Hibernate mapping is simple as an sql-type:

Having <ejbdoclet> generate all the EJB support code and descriptors is great, but the common practice of going from a database to the EJB models takes time. By using XDoclet, we can save an enormous amount of effort by simply creating a single Java file for each bean with the appropriate tags. Perhaps you already have an existing database that you want to reverse engineer into entity beans. This is precisely the purpose of a great tool called Middlegen, created by Aslak Helles y, who is also a member of the XDoclet development team. See figure 14.3.

<property name="email" type="string"> <column name="USER_EMAIL" length="255" not-null="true" sql-type="EMAILADDRESS"/> </property>

<taskdef name="middlegen" classname="middlegen.MiddlegenTask" classpath="${middlegen.jar}" /> <middlegen gui="${gui}" destination="${java.src.dir}" driver="${db.driver}" databaseurl="${db.url}" username="${db.username}" password="${db.password}" schema="${db.schema}" catalog="${db.catalog}" package="org.example.antbook.ejb" interfacepackage="org.example.antbook.interfaces" />

With annotations, declare your own columnDefinition:

The <middlegen> task works in two modes, based on the gui switch: classes may be generated automatically or interactively (the latter through the user interface shown in figure 14.3). Our database schema simply has two tables, Product and Order, which are linked with a one-to-many relationship. The Middlegen task creates a single-entity bean class for each table processed. The code contains the necessary @tags to be further processed by XDoclet s <ejbdoclet> task. Listing 14.3 shows a sample class generated for our Product table.

@Column(name = "USER_EMAIL", length = 255, columnDefinition = "EMAILADDRESS(255) not null") String email;

package org.example.antbook.ejb; /** * @author <a href="http://boss.bekk.no/boss/middlegen/">Middlegen</a> * * @ejb.bean Standard XDoclet container * type="CMP" managed persistence tags * cmp-version="2.x" * name="Product" * local-jndi-name="org.example.antbook.interfaces.ProductLocal" * view-type="local" * * @weblogic:table-name Product * @weblogic:data-source-name middlegen.database Automatic vendor-specific * @weblogic:persistence support added * * @jboss:table-name Product */ public abstract class ProductBean implements javax.ejb.EntityBean {

If you want to create and drop the domain declaration automatically with the rest of your schema, put it into a <database-object> mapping. SQL supports additional column constraints. For example, the business rules allow only alphanumeric characters in user login names:

create table USERS ( ... USERNAME varchar(16) not null check(regexp_like(USERNAME,'^[[:alpha:]]+$')), ... );

/** * Context set by container */ private javax.ejb.EntityContext _entityContext; /** * Returns the productId * * @return the productId * * @ejb.persistent-field * @ejb.pk-field * * @weblogic:dbms-column ProductID * * @jboss:column-name ProductID */ public abstract java.lang.Long getProductId(); // ... some code removed for brevity ... /** * Returns a collection of local Orders * * @return a collection of local Orders * * @ejb.relation * name="product-order" * role-name="product-has-order" * * @weblogic:column-map Relationship with * foreign-key-column="ProductID" Order table * key-column="ProductID" * @jboss:relation * fk-constraint="true" * fk-column="ProductID" * related-pk-field="ProductID" */ public abstract java.util.Collection getOrders(); // ... some code removed for brevity ... }