JacksonJsonProvider (Jackson JSON Processor)

java.lang.Object
- org.codehaus.jackson.jaxrs.JacksonJsonProvider

All Implemented Interfaces:

MessageBodyReader<Object>, MessageBodyWriter<Object>, Versioned

Direct Known Subclasses:

JacksonJaxbJsonProvider
```
@Provider
public class JacksonJsonProvider
extends Object
implements MessageBodyReader<Object>, MessageBodyWriter<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 Summary

Fields
Modifier and Type	Field and Description
`protected boolean`	`_cfgCheckCanDeserialize` Whether we want to actually check that Jackson has a deserializer for given type.
`protected boolean`	`_cfgCheckCanSerialize` Whether we want to actually check that Jackson has a serializer for given type.
`protected HashSet<ClassKey>`	`_cfgCustomUntouchables` Set of types (classes) that provider should ignore for data binding
`protected String`	`_jsonpFunctionName` JSONP function name to use for automatic JSONP wrapping, if any; if null, no JSONP wrapping is done.
`protected MapperConfigurator`	`_mapperConfig` Helper object used for encapsulating configuration aspects of `ObjectMapper`
`protected Providers`	`_providers` Injectable context object used to locate configured instance of `ObjectMapper` to use for actual serialization.
`static Class<?>[]`	`_unreadableClasses` These are classes that we never use for reading (never try to deserialize instances of these types).
`static HashSet<ClassKey>`	`_untouchables` Looks like we need to worry about accidental data binding for types we shouldn't be handling.
`static Class<?>[]`	`_unwritableClasses` These are classes that we never use for writing (never try to serialize instances of these types).
`static Annotations[]`	`BASIC_ANNOTATIONS` Default annotation sets to use, if not explicitly defined during construction: only Jackson annotations are used for the base class.

Constructor Summary

Constructors
Constructor and Description
`JacksonJsonProvider()` Default constructor, usually used when provider is automatically configured to be used with JAX-RS implementation.
`JacksonJsonProvider(Annotations... annotationsToUse)`
`JacksonJsonProvider(ObjectMapper mapper)`
`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 Summary

Methods
Modifier and Type	Method and Description
`protected static boolean`	`_containedIn(Class<?> mainType, HashSet<ClassKey> set)`
`protected Class<?>`	`_findView(ObjectMapper mapper, Annotation[] annotations)`
`void`	`addUntouchable(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).
`void`	`checkCanDeserialize(boolean state)` Method for defining whether actual detection for existence of a deserializer for type should be done when `isReadable(java.lang.Class<?>, java.lang.reflect.Type, java.lang.annotation.Annotation[], javax.ws.rs.core.MediaType)` is called.
`void`	`checkCanSerialize(boolean state)` Method for defining whether actual detection for existence of a serializer for type should be done when `isWriteable(java.lang.Class<?>, java.lang.reflect.Type, java.lang.annotation.Annotation[], javax.ws.rs.core.MediaType)` is called.
`JacksonJsonProvider`	`configure(DeserializationConfig.Feature f, boolean state)`
`JacksonJsonProvider`	`configure(JsonGenerator.Feature f, boolean state)`
`JacksonJsonProvider`	`configure(JsonParser.Feature f, boolean state)`
`JacksonJsonProvider`	`configure(SerializationConfig.Feature f, boolean state)`
`JacksonJsonProvider`	`disable(DeserializationConfig.Feature f, boolean state)`
`JacksonJsonProvider`	`disable(JsonGenerator.Feature f, boolean state)`
`JacksonJsonProvider`	`disable(JsonParser.Feature f, boolean state)`
`JacksonJsonProvider`	`disable(SerializationConfig.Feature f, boolean state)`
`JacksonJsonProvider`	`enable(DeserializationConfig.Feature f, boolean state)`
`JacksonJsonProvider`	`enable(JsonGenerator.Feature f, boolean state)`
`JacksonJsonProvider`	`enable(JsonParser.Feature f, boolean state)`
`JacksonJsonProvider`	`enable(SerializationConfig.Feature f, boolean state)`
`protected JsonEncoding`	`findEncoding(MediaType mediaType, MultivaluedMap<String,Object> httpHeaders)` Helper method to use for determining desired output encoding.
`long`	`getSize(Object value, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)` Method that JAX-RS container calls to try to figure out serialized length of given value.
`protected boolean`	`isJsonType(MediaType mediaType)` Helper method used to check whether given media type is JSON type or sub type.
`boolean`	`isReadable(Class<?> type, Type genericType, Annotation[] annotations, 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.
`boolean`	`isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)` Method that JAX-RS container calls to try to check whether given value (of specified type) can be serialized by this provider.
`ObjectMapper`	`locateMapper(Class<?> type, MediaType mediaType)` Method called to locate `ObjectMapper` to use for serialization and deserialization.
`Object`	`readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String,String> httpHeaders, InputStream entityStream)` Method that JAX-RS container calls to deserialize given value.
`void`	`setAnnotationsToUse(Annotations[] annotationsToUse)` Method for configuring which annotation sets to use (including none).
`void`	`setJSONPFunctionName(String fname)`
`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.
`Version`	`version()` Method that will return version information stored in and read from jar that contains this class.
`void`	`writeTo(Object value, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String,Object> httpHeaders, OutputStream entityStream)` Method that JAX-RS container calls to serialize given value.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 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 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 Class<?>[] _unreadableClasses
```
    These are classes that we never use for reading (never try to deserialize instances of these types).
  - _unwritableClasses
```
public static final Class<?>[] _unwritableClasses
```
    These are classes that we never use for writing (never try to serialize instances of these types).
  - _mapperConfig
```
protected final MapperConfigurator _mapperConfig
```
    Helper object used for encapsulating configuration aspects of ObjectMapper
  - _cfgCustomUntouchables
```
protected HashSet<ClassKey> _cfgCustomUntouchables
```
    Set of types (classes) that provider should ignore for data binding
    
    Since:
    
    1.5
  - _jsonpFunctionName
```
protected String _jsonpFunctionName
```
    JSONP function name to use for automatic JSONP wrapping, if any; if null, no JSONP wrapping is done.
  - _providers
```
@Context
protected 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
  - checkCanDeserialize
```
public void checkCanDeserialize(boolean state)
```
    Method for defining whether actual detection for existence of a deserializer for type should be done when isReadable(java.lang.Class<?>, java.lang.reflect.Type, java.lang.annotation.Annotation[], javax.ws.rs.core.MediaType) is called.
  - checkCanSerialize
```
public void checkCanSerialize(boolean state)
```
    Method for defining whether actual detection for existence of a serializer for type should be done when isWriteable(java.lang.Class<?>, java.lang.reflect.Type, java.lang.annotation.Annotation[], javax.ws.rs.core.MediaType) is called.
  - 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.
  - configure
```
public JacksonJsonProvider configure(DeserializationConfig.Feature f,
                            boolean state)
```
  - configure
```
public JacksonJsonProvider configure(SerializationConfig.Feature f,
                            boolean state)
```
  - configure
```
public JacksonJsonProvider configure(JsonParser.Feature f,
                            boolean state)
```
  - configure
```
public JacksonJsonProvider configure(JsonGenerator.Feature f,
                            boolean state)
```
  - enable
```
public JacksonJsonProvider enable(DeserializationConfig.Feature f,
                         boolean state)
```
  - enable
```
public JacksonJsonProvider enable(SerializationConfig.Feature f,
                         boolean state)
```
  - enable
```
public JacksonJsonProvider enable(JsonParser.Feature f,
                         boolean state)
```
  - enable
```
public JacksonJsonProvider enable(JsonGenerator.Feature f,
                         boolean state)
```
  - disable
```
public JacksonJsonProvider disable(DeserializationConfig.Feature f,
                          boolean state)
```
  - disable
```
public JacksonJsonProvider disable(SerializationConfig.Feature f,
                          boolean state)
```
  - disable
```
public JacksonJsonProvider disable(JsonParser.Feature f,
                          boolean state)
```
  - disable
```
public JacksonJsonProvider disable(JsonGenerator.Feature f,
                          boolean state)
```
  - addUntouchable
```
public void addUntouchable(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(String fname)
```
  - isReadable
```
public boolean isReadable(Class<?> type,
                 Type genericType,
                 Annotation[] annotations,
                 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 MessageBodyReader<Object>
  - readFrom
```
public Object readFrom(Class<Object> type,
              Type genericType,
              Annotation[] annotations,
              MediaType mediaType,
              MultivaluedMap<String,String> httpHeaders,
              InputStream entityStream)
                throws IOException
```
    Method that JAX-RS container calls to deserialize given value.
    
    Specified by:
    
    readFrom in interface MessageBodyReader<Object>
    
    Throws:
    
    IOException
  - getSize
```
public long getSize(Object value,
           Class<?> type,
           Type genericType,
           Annotation[] annotations,
           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 MessageBodyWriter<Object>
  - isWriteable
```
public boolean isWriteable(Class<?> type,
                  Type genericType,
                  Annotation[] annotations,
                  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 MessageBodyWriter<Object>
  - writeTo
```
public void writeTo(Object value,
           Class<?> type,
           Type genericType,
           Annotation[] annotations,
           MediaType mediaType,
           MultivaluedMap<String,Object> httpHeaders,
           OutputStream entityStream)
             throws IOException
```
    Method that JAX-RS container calls to serialize given value.
    
    Specified by:
    
    writeTo in interface MessageBodyWriter<Object>
    
    Throws:
    
    IOException
  - findEncoding
```
protected JsonEncoding findEncoding(MediaType mediaType,
                        MultivaluedMap<String,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(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(Class<?> type,
                        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(Class<?> mainType,
                   HashSet<ClassKey> set)
```
  - _findView
```
protected Class<?> _findView(ObjectMapper mapper,
                 Annotation[] annotations)
                      throws JsonMappingException
```
    Throws:
    
    JsonMappingException

Class JacksonJsonProvider

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

BASIC_ANNOTATIONS

_untouchables

_unreadableClasses

_unwritableClasses

_mapperConfig

_cfgCustomUntouchables

_jsonpFunctionName

_providers

_cfgCheckCanSerialize

_cfgCheckCanDeserialize

Constructor Detail

JacksonJsonProvider

JacksonJsonProvider

JacksonJsonProvider

JacksonJsonProvider

Method Detail

version

checkCanDeserialize

checkCanSerialize

setAnnotationsToUse

setMapper

configure

configure

configure

configure

enable

enable

enable

enable

disable

disable

disable

disable

addUntouchable

setJSONPFunctionName

isReadable

readFrom

getSize

isWriteable

writeTo

findEncoding

isJsonType

locateMapper

_containedIn

_findView