This example demonstrates how to implement generic support for HTTP PATCH Method (RFC-5789) via JAX-RS reader interceptor. The example has been created based on [this Gerard Davison's blogentry] (http://kingsfleet.blogspot.co.uk/2014/02/transparent-patch-support-in-jax-rs-20.html). The patch format supported by this example is JSON Patch (RFC-6902).

The mapping of the URI path space is presented in the following table:

As you can see in the table, there is only a single resource deployed in this application, that supports GET and PATCH methods. The resource represents a patchable state, which consists of 3 properties:

• a title text property,
• a message text property, and
• a list property that represents a list/array of text strings.

This state can be patch via HTTP GET method by sending the desired patch/diff in the JSON Patch format as defined in RFC-6902, for example:

[
  {
    "op" : "replace",
    "path" : "/message",
    "value" : "patchedMessage"
  }, {
    "op" : "add",
    "path" : "/list/-",
    "value" : "one"
  }
]

This patch will instruct the resource to replace it's message property content with a new "patchedMessage" text and also to append a new "one" string value to the list of valued contained in the list property.

(See HttpPatchTest for more details.)

You can apply a patch using curl:

curl -v -X PATCH http://localhost:8080/http-patch/patchable-state -H "Content-Type:application/json-patch+json" -d '[{
   "op": "replace",
   "path": "/message",
   "value": "patchedMessage"
}, {
   "op": "add",
   "path": "/list/-",
   "value": "one"
}]'

The application will answer with a patched object:

{
   "list" : [ "one" ],
   "message" : "patchedMessage",
   "title" : ""
}

Run the example as follows:

mvn clean compile exec:java

This deploys the example using Grizzly container.

A WADL description may be accessed at the URL:

• http://localhost:8080/http-patch/application.wadl

The resource is available at

• http://localhost:8080/http-patch/patchable-state