Learn how to use JiBX to convert XML to Java POJOs and vice versa. In this tutorial, you’ll learn about using the new features of JiBX to generate XML schema definitions easily from existing Java code and to. JiBX Binding Tutorial. Companies are moving more and more towards service oriented architecture (SOA) and SOA services communicate with well formatted.
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For the highest degree of control over JiBX binding behavior you can write custom code that ties directly into the JiBX framework. This gives you ways of handling special cases that are beyond the normal binding flexibility. It’s not a technique to be used lightly, though. Working at this level takes you into the internals of the JiBX runtime implementation classes.
These implementation classes are considered to be reasonably stable, but are likely jjibx change more frequently then the interface classes in the org. They’re also not as well documented as the normal user interface – all you’ll have to work with is this page, the associated example code, and the JavaDocs for the implementation classes in the org. Even with these limitations, the flexibility may be worth the pain involved if you have special binding requirements.
I’ve supplied a pair of examples here which illustrate this flexibility. The JiBX custom code portions of these examples are included in the jibx-extras.
The principle behind custom marshallers and unmarshallers is simple: Instead of letting JiBX build a marshaller and unmarshaller for a class based on a mapping element in your binding definition, you tell JiBX to use your own supplied class. This class must implement the org.
IUnmarshaller for an unmarshaller, used by an input binding interfaces. You can think of custom marshallers and unmarshallers as taking the simpler idea of custom serializers and deserializers tutodial a whole new level. Serializers and deserializers give you control over the text representation of primitive or simple object values, where there’s no XML structure involved. The downside of this extended control is that marshallers and unmarshallers are considerably more complex to code than serializers and deserializers.
Customizing JiBX binding behavior
The Java class structure is based off a Directory rutorial contains a HashMap highlighted in green using customer identifier strings as keys and the associated customer information in the form of Customer class instances as values. The custom marshaller code converts the hashmap into a map element wrapper with an attribute giving the number of key-value pairs, and the actual key-value pairs as contained entry elements all highlighted in magenta.
Each entry element gives the key as an attribute and the mapped value as the content. The custom unmarshaller converts this XML structure back into a hashmap instance. HashMap instances referenced by the binding.
Here the actual binding definition for the tutkrial field highlighted in green automatically uses the custom code.
Mapping xml to java ojects using jibx, examples and developer notes:
In the bottom version, the custom marshaller and unmarshaller are instead referenced directly by the binding definition for the field again highlighted in green. This particular implementation handles one particular form of hashmaps, with string keys and jibs of an object type with a mapping definition within the JiBX binding file. Consider how the XML structure would need to be different if the key values in the hashmap were other mapped objects rather than simple string values, for instance they couldn’t be expressed in XML as attribute values, for starters.
At runtime, JiBX creates an instance of the class when needed using either a default no-argument constructor or an optional aliased constructor that uses element name information passed in from the JiBX binding. For the Figure 21 example JiBX uses the aliased constructor behind the scenes, since the binding definitions supply a name for the mapped element.
If a custom marshaller or unmarshaller class which need not be the same class supports setting the root element name in this way it needs to implement the org. IAliasable interface which is only an indicator interface, with no actual methods defined. This naming flexibility only applies at the top level, though. As you can see from the code, the local names used for the attributes and nested element name are fixed at compile time, while the namespaces are all set to match that of the aliased top-level element which may not be what you want – often documents that use namespaces for elements do not use them for attributes, for instance.
Besides the two constructor variations shown in this example, you can also define constructors that take an additional String parameter. Another interesting issue that’s come up for several users in the past is the need to work with multiple versions of XML documents. JiBX has supported this from the beginning if the versions used different root element names, but this is not a convenient approach for XML versioning – it’s much easier to keep the element names the same and instead just use an attribute of the root element to specify the document version.
This makes a good example of controlling the high-level operation of JiBX from your own code. On the marshalling side, this uses a supplied version string to select the binding:.
To use this binding selection code you need to define a pair of arrays of giving the text values for each tutoriao number and the corresponding binding name, then create the BindingSelector instance and set the document to be unmarshalled before tutoriao calling unmarshalVersioned method to get back the unmarshalled root object:.
A version of this class is also included in the jibx-extras. BindingSelectorso if you just want to make use of it as-is you can easily do so. Customizing JiBX binding behavior.
Start from Code Start from Code. BindGen Example Code Example 1.
Start from Schema Start from Schema. CodeGen Schema Datatype Handling. Example Code Default Generation. Customizations Reference Extensions Reference. Binding Definition Binding Tutorial A basic binding.
Tutkrial details Definition contexts. Subprojects Eclipse Plug-in Introduction. Custom marshallers and unmarshallers The principle behind custom marshallers and unmarshallers is simple: Controlling JiBX with front-end code Another interesting issue that’s come up for several users in the past is the need to work with multiple versions of XML documents. On the marshalling side, this uses a supplied version string to select the binding: Sosnoski Sosnoski Tuforial Associates Ltd.
Licensed to the JiBX Project for free distribution and use.