org.apache.juneau.rest

Interface RestConverter

All Known Implementing Classes:

Introspectable, Queryable, Traversable

public interface RestConverter

REST method response converter.

Implements a filter mechanism for REST method calls that allows response objects to be converted to some other POJO after invocation of the REST method.

Converters are associated with REST methods through the following:

• RestResource.converters()
• RestMethod.converters()
• RestContext.REST_converters
• RestContextBuilder.converters(Class...)
• RestContextBuilder.converters(RestConverter...)

Example:

public class RequestEchoResource extends RestServlet { // GET request handler @RestMethod(name=GET, path="/*", converters={Queryable.class,Traversable.class}) public HttpServletRequest doGet(RestRequest req) { res.setTitle("Contents of HttpServletRequest object"); return req; } }

Converters can also be associated at the servlet level using the @RestResource.converters() annotation.
Applying converters at the resource level is equivalent to applying converters to each resource method individually.

How to implement

Implementers should simply implement the convert(RestRequest, Object) and return back a 'converted' object.
It's up to the implementer to decide what this means.

Subclasses must implement one of the following constructors:

• public T(); // No-arg constructor
• public T(PropertyStore); // Property store of the RestContext

Subclasses can also be defined as inner classes of the resource class.

Predefined converters

• Traversable - Allows URL additional path info to address individual elements in a POJO tree.
• Queryable - Allows query/view/sort functions to be performed on POJOs.
• Introspectable - Allows Java public methods to be invoked on the returned POJOs.

See Also:

• RestContext.REST_converters - Registering converters with REST resources.
• Overview > juneau-rest-server > Converters

Method Summary

Modifier and Type	Method and Description
Object	convert(RestRequest req, Object res) Performs post-call conversion on the specified response object.

Method Detail

convert

Object convert(RestRequest req,
               Object res)
        throws RestException,
               SerializeException

Performs post-call conversion on the specified response object.

Parameters:

req - The servlet request.

res - The response object set by the REST method through the RestResponse.setOutput(Object) method.

Returns:

The converted object.

Throws:

RestException - Thrown if any errors occur during conversion.

SerializeException