JAXB

Now, before all of you start to tell me that this isn't a problem, let me show you what JAXB does do to protect your data.

Right off the bat, JAXB isn't going to be an option for you, as JAXB only accepts XML Schema as a constraint model for class generation.

While JAXB is only focused on a Java-to-XML binding, XML isn't the only kind of data being bound to SDO.

JAXB is robust enough to allow you to name anonymous types as you need to via the binding file.

In fact, JAXB is probably just as flexible as either of the two previous methods shown in terms of setting up output properties.

In closing, let me share with you my cheat sheet, the Ant setup I use to make all my classpath and JAXB samples easy.

This cross-stack compatibility is the main benefit of using JAXB and JAX-WS, since it makes it easy for you to switch between stacks.

These interfaces make JAXB-generated code fairly easy to use with existing documents.

The Castor developers also plan to support JAXB in Castor, probably using some sort of compatibility layer.

It allows configuration of any XML binding mechanism like JAXB, SDO, Castor etc. by implementing the standard framework interface.

Then in October, Sun provided a new beta version of the JAXB reference implementation, finally replacing the long outdated EA version.

The data interchange model can be easily configured by using custom XML serializers, JAXB or any other object-to-XML conversion tools.

Until the production release (currently planned for this quarter), JAXB is not a practical alternative for use in real projects.

This goes on for quite a bit -- notice that JAXB creates a lot of classes for even a relatively simply XML Schema.

Java Architecture for XML Binding (JAXB): Provides a binding compiler and a runtime framework to map Java objects to XML documents.

Since this isn't an article on JAXB basics (for such articles, see Resources), I'll just let you see the code, shown in Listing 3.

A useful feature of JAXB is the ability to validate the source data against the associated schema as part of the unmarshalling operation.

You also need an XML Schema to generate classes and data structures from as you work with JAXB.

This is to be expected in the case of Metro and CXF, since they both use the JAXB reference implementation for conversions.

Zeus code generation is similar in usage to JAXB or Castor, with a command line tool provided to construct the necessary classes.

JAXB also handles CDATA sections a little differently than you might expect, but it does preserve semantic equivalence.

This article focuses on that process -- known as marshalling in the data binding world -- and in particular JAXB's marshalling capabilities.

JAXB introduces the concept of data binding, a correspondence between XML schemas and Java classes.

Interested readers can find such an implementation in the JAXB reference implementation in Resources.

In the long run, this should make it more adaptable than JAXB.

Additionally, since JAX-WS uses JAXB for all data binding purposes, the jaxrpc-mapping file is no longer necessary.

Unlike JAXB, there is no real need of providing annotations for your data binding needs.

Using JAXB, it constructs Java objects corresponding to the input XML elements and puts them in a HashMap.

JAXB binding classes are generated either with the command line tool xjc, or directly in the WebSphere Integration Developer environment.

To use this file yourself, simply modify the paths to your own XML input files, as well as to your JAXB JAR files.

At this point, carefully analyze which type of XML binding is appropriate (JAX-RPC, JAXB, and so on).

JAXB still looks like a good choice for the code generation approach in the future (the beta license only allows evaluation use).

JAXB is still going to generate a class that accepts a string argument, based on the usage of the.

This will include trying out some of the customization options JAXB provides.

As mentioned earlier, JAX-WS relies on JAXB to handle the data binding for most of its Web services content.

Note that the implementation classes are only instantiated through a factory class that is generated by the JAXB compiler.

Now you can instruct JAXB to spit the in-memory representation back out to XML.

JAXB is still immature -- this is still the first major release of a fairly new technology.

Generating code from a Schema description is as easy with Castor as with JAXB, and uses the same basic options.

The binding process generates JAXB classes with additional COBOL annotations.

With your classes generated and ready for use, you're all set to unmarshal the XML document from Listing 1 into JAXB's in-memory model.

Additionally, you don't need much XML knowledge at all to use JAXB.

At runtime, JAXB libraries are used in marshalling and unmarshalling.

The line in Listing 14 tells the JAXB runtime to report if the data does not conform to the schema.

These are all freely available, and with the exception of JAXB, are usable in both open source and proprietary projects.

JAXB and Castor are designed to work with documents on file, and Axis works with Web services.

This method must use XML to Java object binding and it uses JAXB for that.

Finally, you'll want to copy over the support files used: Configuration. xml and jaxb. properties.

You'd generate the same data model if you ran the JAXB XJC binding compiler directly on the schemas used by a Web service.

All of this often leads developers to either put JAXB down, or learn a lot more about XML, SAX, and DOM.

For those cases where you cannot change the schema, JAXB provides another solution.

Get the JAXB context for your application.

Other than the interfaces and the implementation classes, JAXB-specific classes are generated.

JAXB, Quick, and Zeus all turn in respectable performance figures compared to dom4j, but take nearly twice as long as JiBX overall.

In Java EE 6, JAXB offers improved performance through marshalling optimizations enabled by default.

SDO also offers both a static and dynamic API*, whereas JAXB only provides a static binding.

JAXB automatically inserted this line into the output.

You used the XSD file in conjunction with JAXB to create a suite of associated Java classes.

If you want better support for XML schema through JAXB.

Let's make this more concrete by introducing another technology: JAXB.

JAXB is a technology from Sun that provides some basic capabilities.

JAX-WS, via JAXB, adds support for MTOM, the new attachment specification.

JAXB introduces the idea of data binding to create a correspondence between XML schemas and Java classes.

JAXB provides a convenient way to bind an XML schema to a representation in Java code.

I will provide more information on representation techniques, and especially on the JAXB element representation, later in this article.

In this article, I'll introduce the JaxMe project, which keeps most of JAXB's good features, and dumps many of its problems.

Castor's support for code generation differs in details from the JAXB approach, but is very similar in intent.

JAXB supports both generating code from schemas, as in this case, and starting from code.

The wsimport tool takes a WSDL file as input and generates the necessary SEI, service, and JAXB classes.

Complex data types are first converted into XML using JAXB and then passed to the service invoker.

Again, JAXB makes the marshalling process easy.

The JAXB schema compiler creates Java classes and interfaces based on the structure of the XML schema, typically at development time.

There are actually two different JAXB contexts that we use in the sample application.

This step is required to override the JAXB classes built into the Java software development kit (JDK) version 1. 5. x.

To ease and streamline this mapping process, use JAXB.

Since March, the JAXB project has been moving forward in this new direction.

JAXB 2. x uses annotations in the data model classes to control how data is converted to and from XML.

Support for basic JDOQL querying of objects stored in LDAP via JDO, utilizing JAXB.

You will need the JAXB compile and runtime libraries included in this package to do the steps in this article.

The XML serialization mechanism (based on JAXB 2. 0) is also used to convert complex objects between different class loaders.

Now I'll briefly go through them and give you a close look at the JAXB representation.

For more advanced topics using JAXB see the project home in Resources.

Generating code from a Schema description is very simple with JAXB.

You may even find that in many cases, XPath is a better tool for data binding than working with generated classes and an API such as JAXB.

Unfortunately, there's no way to use a separately generated JAXB data model in WSDL2Java code generation.

The JAXB customizations also follow the rules of XML schema.

Finally, I assume that you have JAXB set up and running.

Castor is also expected to support the coming JAXB standard in the future.

Listing 2 illustrates a full JAXB program.

JAXB promises mappings for all XML schemas.

JAX-WS's data mapping model is JAXB.

While these are similar to the constructs created by JAXB, you'll find a few subtle differences.

We have discussed the need to adapt to frequently changing XSDs, and we saw how JAXB can help in getting that done.

Now, look at the setup required for JAXB.

JAXB does have some weaknesses, however.

This is the first step in testing out JAXB's round-tripping capabilities.

Notice how Listing 4 reproduces the data in Listing 2 thanks to JAXB.

Future versions of Jibx2Wsdl may also support using JAXB 2. 0 and JAX-WS annotations as customizations.

JAX-WS is built around its tight integration with JAXB 2. 0.

I discuss the SAX API of AXIOM here because some data binding frameworks won't work with anything else -- JAXB, for example.

Use of standard, open, technologies such as XML Schema, JAXB, JAX-WS, JMS or HTTP guarantees that a large community will keep them alive.

For example, JAXB code works with JAXB-compliant APIs, like JAXB's reference implementation and JaxMe.

However, the JAXB API (or architecture, if you like) has some deficiencies, and doesn't get updated very often.

The JAXB specification defines ways to customize several aspects of the generated data binding by using binding declarations. These include

Finally parsing occurs, you then return to the JAXB framework with this last call