org.opentripplanner.api.model

Class JSONObjectMapperProvider

java.lang.Object

org.opentripplanner.api.model.JSONObjectMapperProvider

All Implemented Interfaces:

javax.ws.rs.ext.ContextResolver<com.fasterxml.jackson.databind.ObjectMapper>

@Provider
 @Produces(value="application/json")
public class JSONObjectMapperProvider
extends Object
implements javax.ws.rs.ext.ContextResolver<com.fasterxml.jackson.databind.ObjectMapper>

AgencyAndId is a third-party class in One Bus Away which represents a GTFS element's ID, including an agency name as identifier scope information since more than one feed may be loaded at once. While this works when there is only one agency per feed, the true scope of identifiers is the feed, and the same agency could appear in multiple feeds. We don't want the key "agencyId" to appear in the final OTP API because it will eventually not represent an agency. See this ticket: https://github.com/opentripplanner/OpenTripPlanner/issues/1352 And this proposal to gtfs-changes: https://groups.google.com/d/msg/gtfs-changes/zVjEoNIPr_Y/4ngWCajPoS0J Our solution is to serialize the AgencyAndId as a single string with a separator character between the agency and ID. In future versions this scoped identifier will actually represent a feed and ID. The important thing is that the API will remain the same, and identifiers fetched from one API result can be used in another request with no conflicts. Since AgencyAndId is a third-party class, we can't modify it with a custom serialization method or annotations. Instead, we have to let Jackson know which custom serializer class applies to the third-party type. According to http://wiki.fasterxml.com/JacksonHowToCustomSerializers "Jackson 1.7 added ability to register serializers and deserializes via Module interface. This is the recommended way to add custom serializers." A Jackson "Module" is a group of extensions to default functionality, used for example to support serializing new data types. Modules are registered with an ObjectMapper, which constructs ObjectWriters, which are used to do the final JSON writing. In OTP the ObjectWriter construction and JSON writing are performed automatically by Jersey.

Constructor Summary

Constructors

Constructor and Description
JSONObjectMapperProvider() Pre-instantiate a Jackson ObjectMapper that will be handed off to all incoming Jersey requests, and used to construct the ObjectWriters that will produce JSON responses.

Method Summary

Modifier and Type	Method and Description
com.fasterxml.jackson.databind.ObjectMapper	getContext(Class<?> type) When serializing any kind of result, use the same ObjectMapper.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JSONObjectMapperProvider

public JSONObjectMapperProvider()

Pre-instantiate a Jackson ObjectMapper that will be handed off to all incoming Jersey requests, and used to construct the ObjectWriters that will produce JSON responses.

Method Detail

getContext

public com.fasterxml.jackson.databind.ObjectMapper getContext(Class<?> type)

When serializing any kind of result, use the same ObjectMapper. The "type" parameter will be the type of the object being serialized, so you could provide different ObjectMappers for different result types.

Specified by:

getContext in interface javax.ws.rs.ext.ContextResolver<com.fasterxml.jackson.databind.ObjectMapper>