Java API for JSON Processing (JSR-353) - Stream APIs

Java will soon have a standard set of APIs for processing JSON as part of Java EE 7.  This standard is being defined as JSR 353 - Java API for JSON Processing (JSON-P) and it is currently at the Final Approval Ballot.  JSON-P offers both object oriented and stream based approaches, in this post I will introduce the stream APIs.

You can get JSON-P reference implementation from the link below:

• http://java.net/projects/jsonp/

UPDATE

JSR-353 has passed the final approval ballot.

• http://www.jcp.org/en/jsr/results?id=5486

MOXy and JSON with Padding

JSON with padding is a communication mechanism used in JavaScript to overcome restrictions due to the same origin policy (for more information see: http://en.wikipedia.org/wiki/JSONP).  In this post I will demonstrate how to leverage JSON with padding when using MOXy as your JSON provider.

This functionality is new in EclipseLink 2.5.0 (and 2.4.2), you can try it out today using a nightly build available from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

MOXy's Object Graphs & Dynamic JAXB

JAXB (JSR-222) makes it easy for you to convert instances of your domain classes to/from XML.  The EclipseLink MOXy implementation offers an extension called Dynamic JAXB where instead of real classes you have instances of a map like class called DynamicEntity. You can access the data on your DynamicEntity using get and set methods that take the property name (i.e. customer.get("address") and customer.set('name", "Jane Doe").

In this post, first we will bootstrap a dynamic JAXBContext based on an external mapping file.  Then we unmarshal an XML document to dynamic entities, and finally we will apply an object graph to scope the resulting JSON output.

You can try this out today by downloading an EclipseLink 2.5.0 nightly download starting on March 24, 2013 from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

MOXy's Object Graphs - Partial Models on the Fly to/from XML & JSON

In a previous post I introduced how MOXy's Object Graph feature allows you to input and output partial models.  In that example I demonstrated how to define a partial model via metadata.  In this example we will create the object graphs programmatically.  This gives you additional flexibility when you need to create one on the fly.

You can try this out today by downloading an EclipseLink 2.5.0 nightly download starting on March 24, 2013 from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

MOXy's Object Graphs - Input/Output Partial Models to XML & JSON

Suppose you have a domain model that you want to expose as a RESTful service.  The problem is you only want to input/output part of your data.  Previously you would have created a separate model representing  the subset and then have code to move data between the models.  In EclipseLink 2.5.0 we have a new feature called Object Graphs that enables you to easily define partial views on your model.

You can try this out today by downloading an EclipseLink 2.5.0 nightly download starting on March 24, 2013 from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

Binding to JSON & XML - Handling Collections

One of EclipseLink JAXB (MOXy)'s strengths is the ability to map an object model to both JSON and XML with a single set of metadata.  The one weakness had been that you needed to compromise on the JSON key or XML element for collection properties.  I'm happy to say that this issue has been solved in EclipseLink 2.5 (and EclipseLink 2.4.2), and I will demonstrate below with an example.

You can try this out today by downloading an EclipseLink 2.5.0 (or EclipseLink 2.4.2) nightly build starting on March 15, 2013 from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

JAXB and java.util.Map

Is it ironic that it can be difficult to map the java.util.Map class in JAXB (JSR-222)?  In this post I will cover some items that will make it much easier.

MOXy's @XmlInverseReference is now Truly Bidirectional

EclipseLink JAXB (MOXy)'s @XmlInverseReference annotation enables you to map a back pointer during the unmarshal operation (useful when mapping JPA entities).  The problem was it acted like @XmlTransient during the marshal operation.  This means that previously it could only be used in one direction.  Now I'm happy to announce in EclipseLink 2.5.0 we have expanded @XmlInverseReference so that the corresponding property may be writeable enabling it to be used in both directions.

You can try this out today by downloading one EclipseLink 2.5.0 nightly downloads starting on March 1, 2013 from:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

Leveraging MOXy in your Web Service via JAX-WS Provider

In previous articles I demonstrated how EclipseLink JAXB (MOXy) is directly integrated into the JAX-WS implementations in WebLogic (as of 12.1.1) and in GlassFish (as of 3.1.2).  In this post I'll demonstrate how to leverage MOXy in any application server by using the JAX-WS Provider class.

JAXB's @XmlAnyElement(lax=true) Explained

In a previous post I introduced how the @XmlAnyElement(lax=true) annotation could be used to create a very flexible mapping.  In this post I'll dig a bit deeper into how it relates to both the @XmlRootElement and @XmlElementDecl.