Class JacksonJsonProvider

  • All Implemented Interfaces:
    javax.ws.rs.ext.MessageBodyReader<java.lang.Object>, javax.ws.rs.ext.MessageBodyWriter<java.lang.Object>, Versioned
    Direct Known Subclasses:
    JacksonJaxbJsonProvider

    @Provider
    public class JacksonJsonProvider
    extends java.lang.Object
    implements javax.ws.rs.ext.MessageBodyReader<java.lang.Object>, javax.ws.rs.ext.MessageBodyWriter<java.lang.Object>, Versioned
    Basic implementation of JAX-RS abstractions (MessageBodyReader, MessageBodyWriter) needed for binding JSON ("application/json") content to and from Java Objects ("POJO"s).

    Actual data binding functionality is implemented by ObjectMapper: mapper to use can be configured in multiple ways:

    • By explicitly passing mapper to use in constructor
    • By explictly setting mapper to use by setMapper(org.codehaus.jackson.map.ObjectMapper)
    • By defining JAX-RS Provider that returns ObjectMappers.
    • By doing none of above, in which case a default mapper instance is constructed (and configured if configuration methods are called)
    The last method ("do nothing specific") is often good enough; explicit passing of Mapper is simple and explicit; and Provider-based method may make sense with Depedency Injection frameworks, or if Mapper has to be configured differently for different media types.

    Note that the default mapper instance will be automatically created if one of explicit configuration methods (like configure(org.codehaus.jackson.map.DeserializationConfig.Feature, boolean)) is called: if so, Provider-based introspection is NOT used, but the resulting Mapper is used as configured.

    Note: version 1.3 added a sub-class (JacksonJaxbJsonProvider) which is configured by default to use both Jackson and JAXB annotations for configuration (base class when used as-is defaults to using just Jackson annotations)

    Author:
    Tatu Saloranta
    • Field Detail

      • BASIC_ANNOTATIONS

        public static final Annotations[] BASIC_ANNOTATIONS
        Default annotation sets to use, if not explicitly defined during construction: only Jackson annotations are used for the base class. Sub-classes can use other settings.
      • _untouchables

        public static final java.util.HashSet<ClassKey> _untouchables
        Looks like we need to worry about accidental data binding for types we shouldn't be handling. This is probably not a very good way to do it, but let's start by blacklisting things we are not to handle.

        (why ClassKey? since plain old Class has no hashCode() defined, lookups are painfully slow)

      • _unreadableClasses

        public static final java.lang.Class<?>[] _unreadableClasses
        These are classes that we never use for reading (never try to deserialize instances of these types).
      • _unwritableClasses

        public static final java.lang.Class<?>[] _unwritableClasses
        These are classes that we never use for writing (never try to serialize instances of these types).
      • _cfgCustomUntouchables

        protected java.util.HashSet<ClassKey> _cfgCustomUntouchables
        Set of types (classes) that provider should ignore for data binding
        Since:
        1.5
      • _jsonpFunctionName

        protected java.lang.String _jsonpFunctionName
        JSONP function name to use for automatic JSONP wrapping, if any; if null, no JSONP wrapping is done.
      • _providers

        @Context
        protected javax.ws.rs.ext.Providers _providers
        Injectable context object used to locate configured instance of ObjectMapper to use for actual serialization.
      • _cfgCheckCanSerialize

        protected boolean _cfgCheckCanSerialize
        Whether we want to actually check that Jackson has a serializer for given type. Since this should generally be the case (due to auto-discovery) and since the call to check availability can be bit expensive, defaults to false.
      • _cfgCheckCanDeserialize

        protected boolean _cfgCheckCanDeserialize
        Whether we want to actually check that Jackson has a deserializer for given type. Since this should generally be the case (due to auto-discovery) and since the call to check availability can be bit expensive, defaults to false.
    • Constructor Detail

      • JacksonJsonProvider

        public JacksonJsonProvider()
        Default constructor, usually used when provider is automatically configured to be used with JAX-RS implementation.
      • JacksonJsonProvider

        public JacksonJsonProvider​(Annotations... annotationsToUse)
        Parameters:
        annotationsToUse - Annotation set(s) to use for configuring data binding
      • JacksonJsonProvider

        public JacksonJsonProvider​(ObjectMapper mapper)
      • JacksonJsonProvider

        public JacksonJsonProvider​(ObjectMapper mapper,
                                   Annotations[] annotationsToUse)
        Constructor to use when a custom mapper (usually components like serializer/deserializer factories that have been configured) is to be used.
    • Method Detail

      • version

        public Version version()
        Method that will return version information stored in and read from jar that contains this class.
        Specified by:
        version in interface Versioned
        Since:
        1.6
      • setAnnotationsToUse

        public void setAnnotationsToUse​(Annotations[] annotationsToUse)
        Method for configuring which annotation sets to use (including none). Annotation sets are defined in order decreasing precedence; that is, first one has the priority over following ones.
        Parameters:
        annotationsToUse - Ordered list of annotation sets to use; if null, default
      • setMapper

        public void setMapper​(ObjectMapper m)
        Method that can be used to directly define ObjectMapper to use for serialization and deserialization; if null, will use the standard provider discovery from context instead. Default setting is null.
      • addUntouchable

        public void addUntouchable​(java.lang.Class<?> type)
        Method for marking specified type as "untouchable", meaning that provider will not try to read or write values of this type (or its subtypes).
        Parameters:
        type - Type to consider untouchable; can be any kind of class, including abstract class or interface. No instance of this type (including subtypes, i.e. types assignable to this type) will be read or written by provider
        Since:
        1.5
      • setJSONPFunctionName

        public void setJSONPFunctionName​(java.lang.String fname)
      • isReadable

        public boolean isReadable​(java.lang.Class<?> type,
                                  java.lang.reflect.Type genericType,
                                  java.lang.annotation.Annotation[] annotations,
                                  javax.ws.rs.core.MediaType mediaType)
        Method that JAX-RS container calls to try to check whether values of given type (and media type) can be deserialized by this provider. Implementation will first check that expected media type is a JSON type (via call to isJsonType(javax.ws.rs.core.MediaType); then verify that type is not one of "untouchable" types (types we will never automatically handle), and finally that there is a deserializer for type (iff checkCanDeserialize(boolean) has been called with true argument -- otherwise assumption is there will be a handler)
        Specified by:
        isReadable in interface javax.ws.rs.ext.MessageBodyReader<java.lang.Object>
      • readFrom

        public java.lang.Object readFrom​(java.lang.Class<java.lang.Object> type,
                                         java.lang.reflect.Type genericType,
                                         java.lang.annotation.Annotation[] annotations,
                                         javax.ws.rs.core.MediaType mediaType,
                                         javax.ws.rs.core.MultivaluedMap<java.lang.String,​java.lang.String> httpHeaders,
                                         java.io.InputStream entityStream)
                                  throws java.io.IOException
        Method that JAX-RS container calls to deserialize given value.
        Specified by:
        readFrom in interface javax.ws.rs.ext.MessageBodyReader<java.lang.Object>
        Throws:
        java.io.IOException
      • getSize

        public long getSize​(java.lang.Object value,
                            java.lang.Class<?> type,
                            java.lang.reflect.Type genericType,
                            java.lang.annotation.Annotation[] annotations,
                            javax.ws.rs.core.MediaType mediaType)
        Method that JAX-RS container calls to try to figure out serialized length of given value. Since computation of this length is about as expensive as serialization itself, implementation will return -1 to denote "not known", so that container will determine length from actual serialized output (if needed).
        Specified by:
        getSize in interface javax.ws.rs.ext.MessageBodyWriter<java.lang.Object>
      • isWriteable

        public boolean isWriteable​(java.lang.Class<?> type,
                                   java.lang.reflect.Type genericType,
                                   java.lang.annotation.Annotation[] annotations,
                                   javax.ws.rs.core.MediaType mediaType)
        Method that JAX-RS container calls to try to check whether given value (of specified type) can be serialized by this provider. Implementation will first check that expected media type is a JSON type (via call to isJsonType(javax.ws.rs.core.MediaType); then verify that type is not one of "untouchable" types (types we will never automatically handle), and finally that there is a serializer for type (iff checkCanSerialize(boolean) has been called with true argument -- otherwise assumption is there will be a handler)
        Specified by:
        isWriteable in interface javax.ws.rs.ext.MessageBodyWriter<java.lang.Object>
      • writeTo

        public void writeTo​(java.lang.Object value,
                            java.lang.Class<?> type,
                            java.lang.reflect.Type genericType,
                            java.lang.annotation.Annotation[] annotations,
                            javax.ws.rs.core.MediaType mediaType,
                            javax.ws.rs.core.MultivaluedMap<java.lang.String,​java.lang.Object> httpHeaders,
                            java.io.OutputStream entityStream)
                     throws java.io.IOException
        Method that JAX-RS container calls to serialize given value.
        Specified by:
        writeTo in interface javax.ws.rs.ext.MessageBodyWriter<java.lang.Object>
        Throws:
        java.io.IOException
      • findEncoding

        protected JsonEncoding findEncoding​(javax.ws.rs.core.MediaType mediaType,
                                            javax.ws.rs.core.MultivaluedMap<java.lang.String,​java.lang.Object> httpHeaders)
        Helper method to use for determining desired output encoding. For now, will always just use UTF-8...
        Since:
        1.7.0
      • isJsonType

        protected boolean isJsonType​(javax.ws.rs.core.MediaType mediaType)
        Helper method used to check whether given media type is JSON type or sub type. Current implementation essentially checks to see whether MediaType.getSubtype() returns "json" or something ending with "+json".
      • locateMapper

        public ObjectMapper locateMapper​(java.lang.Class<?> type,
                                         javax.ws.rs.core.MediaType mediaType)
        Method called to locate ObjectMapper to use for serialization and deserialization. If an instance has been explicitly defined by setMapper(org.codehaus.jackson.map.ObjectMapper) (or non-null instance passed in constructor), that will be used. If not, will try to locate it using standard JAX-RS ContextResolver mechanism, if it has been properly configured to access it (by JAX-RS runtime). Finally, if no mapper is found, will return a default unconfigured ObjectMapper instance (one constructed with default constructor and not modified in any way)
        Parameters:
        type - Class of object being serialized or deserialized; not checked at this point, since it is assumed that unprocessable classes have been already weeded out, but will be passed to ContextResolver as is.
        mediaType - Declared media type for the instance to process: not used by this method, but will be passed to ContextResolver as is.
      • _containedIn

        protected static boolean _containedIn​(java.lang.Class<?> mainType,
                                              java.util.HashSet<ClassKey> set)