Package edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.deser.std

Class StdDelegatingDeserializer<T>

java.lang.Object
edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.JsonDeserializer<T>
edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.deser.std.StdDeserializer<T>
edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.deser.std.StdDelegatingDeserializer<T>
Type Parameters:
T - Target type to convert to, from delegate type
All Implemented Interfaces:
ContextualDeserializer, NullValueProvider, ResolvableDeserializer, ValueInstantiator.Gettable, Serializable
public class StdDelegatingDeserializer<T> extends StdDeserializer<T> implements ContextualDeserializer, ResolvableDeserializer
Deserializer implementation where given Java type is first deserialized by a standard Jackson deserializer into a delegate type; and then this delegate type is converted using a configured Converter into desired target type. Common delegate types to use are Map and JsonNode.

Note that although types (delegate, target) may be related, they must not be same; trying to do this will result in an exception.

Since 2.5 There is StdNodeBasedDeserializer that is a simplified version for cases where intermediate type is JsonNode

Since:
2.1
See Also:

  • Field Details

    • _converter

      protected final Converter<Object,T> _converter
      Converter that was used for creating _delegateDeserializer.

    • _delegateType

      protected final JavaType _delegateType
      Fully resolved delegate type, with generic information if any available.

    • _delegateDeserializer

      protected final JsonDeserializer<Object> _delegateDeserializer
      Underlying serializer for type T.

  • Constructor Details

  • Method Details

    • withDelegate

      protected StdDelegatingDeserializer<T> withDelegate(Converter<Object,T> converter, JavaType delegateType, JsonDeserializer<?> delegateDeserializer)
      Method used for creating resolved contextual instances. Must be overridden when sub-classing.

    • resolve

      public void resolve(DeserializationContext ctxt) throws JsonMappingException
      Description copied from interface: ResolvableDeserializer
      Method called after deserializer instance has been constructed (and registered as necessary by provider objects), but before it has returned it to the caller. Called object can then resolve its dependencies to other types, including self-references (direct or indirect).
      Specified by:
      resolve in interface ResolvableDeserializer
      Parameters:
      ctxt - Context to use for accessing configuration, resolving secondary deserializers
      Throws:
      JsonMappingException

    • createContextual

      public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException
      Description copied from interface: ContextualDeserializer
      Method called to see if a different (or differently configured) deserializer is needed to deserialize values of specified property. Note that instance that this method is called on is typically shared one and as a result method should NOT modify this instance but rather construct and return a new instance. This instance should only be returned as-is, in case it is already suitable for use.
      Specified by:
      createContextual in interface ContextualDeserializer
      Parameters:
      ctxt - Deserialization context to access configuration, additional deserializers that may be needed by this deserializer
      property - Method, field or constructor parameter that represents the property (and is used to assign deserialized value). Should be available; but there may be cases where caller cannot provide it and null is passed instead (in which case impls usually pass 'this' deserializer as is)
      Returns:
      Deserializer to use for deserializing values of specified property; may be this instance or a new instance.
      Throws:
      JsonMappingException

    • deserialize

      public T deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
      Description copied from class: JsonDeserializer
      Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles. Returned instance is to be constructed by method itself.

      Pre-condition for this method is that the parser points to the first event that is part of value to deserializer (and which is never JSON 'null' literal, more on this below): for simple types it may be the only value; and for structured types the Object start marker or a FIELD_NAME.

      The two possible input conditions for structured types result from polymorphism via fields. In the ordinary case, Jackson calls this method when it has encountered an OBJECT_START, and the method implementation must advance to the next token to see the first field name. If the application configures polymorphism via a field, then the object looks like the following. 

            {
          "@class": "class name",
          ...
      }
      Jackson consumes the two tokens (the @class field name and its value) in order to learn the class and select the deserializer. Thus, the stream is pointing to the FIELD_NAME for the first field after the @class. Thus, if you want your method to work correctly both with and without polymorphism, you must begin your method with: 
             if (p.currentToken() == JsonToken.START_OBJECT) {
         p.nextToken();
       }
      This results in the stream pointing to the field name, so that the two conditions align.

      Post-condition is that the parser will point to the last event that is part of deserialized value (or in case deserialization fails, event that was not recognized or usable, which may be the same event as the one it pointed to upon call).

      Note that this method is never called for JSON null literal, and thus deserializers need (and should) not check for it.

      Specified by:
      deserialize in class JsonDeserializer<T>
      Parameters:
      p - Parsed used for reading JSON content
      ctxt - Context that can be used to access information about this deserialization activity.
      Returns:
      Deserialized value
      Throws:
      IOException

    • deserializeWithType

      public Object deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws IOException
      Description copied from class: StdDeserializer
      Base implementation that does not assume specific type inclusion mechanism. Sub-classes are expected to override this method if they are to handle type information.
      Overrides:
      deserializeWithType in class StdDeserializer<T>
      typeDeserializer - Deserializer to use for handling type information
      Throws:
      IOException

    • deserialize

      public T deserialize(JsonParser p, DeserializationContext ctxt, Object intoValue) throws IOException
      Description copied from class: JsonDeserializer
      Alternate deserialization method (compared to the most commonly used, JsonDeserializer.deserialize(JsonParser, DeserializationContext)), which takes in initialized value instance, to be configured and/or populated by deserializer. Method is not necessarily used (or supported) by all types (it will not work for immutable types, for obvious reasons): most commonly it is used for Collections and Maps. It may be used both with "updating readers" (for POJOs) and when Collections and Maps use "getter as setter".

      Default implementation just throws UnsupportedOperationException, to indicate that types that do not explicitly add support do not necessarily support update-existing-value operation (esp. immutable types)

      Overrides:
      deserialize in class JsonDeserializer<T>
      Throws:
      IOException

    • _handleIncompatibleUpdateValue

      protected Object _handleIncompatibleUpdateValue(JsonParser p, DeserializationContext ctxt, Object intoValue) throws IOException
      Overridable handler method called when deserialize(JsonParser, DeserializationContext, Object) has been called with a value that is not compatible with delegate value. Since no conversion are expected for such "updateValue" case, this is normally not an operation that can be permitted, and the default behavior is to throw exception. Sub-classes may choose to try alternative approach if they have more information on exact usage and constraints.
      Throws:
      IOException
      Since:
      2.6

    • handledType

      public Class<?> handledType()
      Description copied from class: JsonDeserializer
      Method for accessing concrete physical type of values this deserializer produces. Note that this information is not guaranteed to be exact -- it may be a more generic (super-type) -- but it should not be incorrect (return a non-related type).

      Default implementation will return null, which means almost same same as returning Object.class would; that is, that nothing is known about handled type.

      Overrides:
      handledType in class StdDeserializer<T>
      Returns:
      Physical type of values this deserializer produces, if known; null if not

    • logicalType

      public LogicalType logicalType()
      Description copied from class: JsonDeserializer
      Method for accessing logical type of values this deserializer produces. Typically used for further configuring handling of values, for example, to find which coercions are legal.
      Overrides:
      logicalType in class JsonDeserializer<T>
      Returns:
      Logical type of values this deserializer produces, if known; null if not

    • isCachable

      public boolean isCachable()
      Description copied from class: JsonDeserializer
      Method called to see if deserializer instance is cachable and usable for other properties of same type (type for which instance was created).

      Note that cached instances are still resolved on per-property basis, if instance implements ResolvableDeserializer: cached instance is just as the base. This means that in most cases it is safe to cache instances; however, it only makes sense to cache instances if instantiation is expensive, or if instances are heavy-weight.

      Default implementation returns false, to indicate that no caching is done.

      Overrides:
      isCachable in class JsonDeserializer<T>

    • getDelegatee

      public JsonDeserializer<?> getDelegatee()
      Description copied from class: JsonDeserializer
      Accessor that can be used to determine if this deserializer uses another deserializer for actual deserialization, by delegating calls. If so, will return immediate delegate (which itself may delegate to further deserializers); otherwise will return null.
      Overrides:
      getDelegatee in class JsonDeserializer<T>
      Returns:
      Deserializer this deserializer delegates calls to, if null; null otherwise.

    • getKnownPropertyNames

      public Collection<Object> getKnownPropertyNames()
      Description copied from class: JsonDeserializer
      Method that will either return null to indicate that type being deserializers has no concept of properties; or a collection of identifiers for which toString will give external property name. This is only to be used for error reporting and diagnostics purposes (most commonly, to accompany "unknown property" exception).
      Overrides:
      getKnownPropertyNames in class JsonDeserializer<T>

    • getNullValue

      public T getNullValue(DeserializationContext ctxt) throws JsonMappingException
      Description copied from class: JsonDeserializer
      Method that can be called to determine value to be used for representing null values (values deserialized when JSON token is JsonToken.VALUE_NULL). Usually this is simply Java null, but for some types (especially primitives) it may be necessary to use non-null values.

      This method may be called once, or multiple times, depending on what JsonDeserializer.getNullAccessPattern() returns.

      Default implementation simply returns null.

      Specified by:
      getNullValue in interface NullValueProvider
      Overrides:
      getNullValue in class JsonDeserializer<T>
      Throws:
      JsonMappingException

    • getNullAccessPattern

      public AccessPattern getNullAccessPattern()
      Description copied from class: JsonDeserializer
      This method may be called in conjunction with calls to JsonDeserializer.getNullValue(DeserializationContext), to check whether it needs to be called just once (static values), or each time empty value is needed.

      Default implementation indicates that the "null value" to use for input null does not vary across uses so that JsonDeserializer.getNullValue(DeserializationContext) need not be called more than once per deserializer instance. This information may be used as optimization.

      Specified by:
      getNullAccessPattern in interface NullValueProvider
      Overrides:
      getNullAccessPattern in class JsonDeserializer<T>

    • getAbsentValue

      public Object getAbsentValue(DeserializationContext ctxt) throws JsonMappingException
      Description copied from class: JsonDeserializer
      Method called to determine placeholder value to be used for cases where no value was obtained from input but we must pass a value nonetheless: the common case is that of Creator methods requiring passing a value for every parameter. Usually this is same as JsonDeserializer.getNullValue(edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.DeserializationContext) (which in turn is usually simply Java null), but it can be overridden for specific types: most notable scalar types must use "default" values.

      This method needs to be called every time a determination is made.

      Default implementation simply calls JsonDeserializer.getNullValue(edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.DeserializationContext) and returns value.

      Specified by:
      getAbsentValue in interface NullValueProvider
      Overrides:
      getAbsentValue in class JsonDeserializer<T>
      Throws:
      JsonMappingException

    • getEmptyValue

      public Object getEmptyValue(DeserializationContext ctxt) throws JsonMappingException
      Description copied from class: JsonDeserializer
      Method called to determine value to be used for "empty" values (most commonly when deserializing from empty JSON Strings). Usually this is same as JsonDeserializer.getNullValue(edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.DeserializationContext) (which in turn is usually simply Java null), but it can be overridden for specific types. Or, if type should never be converted from empty String, method can also throw an exception.

      This method may be called once, or multiple times, depending on what JsonDeserializer.getEmptyAccessPattern() returns.

      Default implementation simply calls JsonDeserializer.getNullValue(edu.internet2.middleware.grouperClientExt.com.fasterxml.jackson.databind.DeserializationContext) and returns value.

      Overrides:
      getEmptyValue in class JsonDeserializer<T>
      Throws:
      JsonMappingException

    • getEmptyAccessPattern

      public AccessPattern getEmptyAccessPattern()
      Description copied from class: JsonDeserializer
      This method may be called in conjunction with calls to JsonDeserializer.getEmptyValue(DeserializationContext), to check whether it needs to be called just once (static values), or each time empty value is needed.
      Overrides:
      getEmptyAccessPattern in class JsonDeserializer<T>

    • supportsUpdate

      public Boolean supportsUpdate(DeserializationConfig config)
      Description copied from class: JsonDeserializer
      Introspection method that may be called to see whether deserializer supports update of an existing value (aka "merging") or not. Return value should either be Boolean.FALSE if update is not supported at all (immutable values); Boolean.TRUE if update should usually work (regular POJOs, for example), or null if this is either not known, or may sometimes work.

      Information gathered is typically used to either prevent merging update for property (either by skipping, if based on global defaults; or by exception during deserializer construction if explicit attempt made) if Boolean.FALSE returned, or inclusion if Boolean.TRUE is specified. If "unknown" case (null returned) behavior is to exclude property if global defaults used; or to allow if explicit per-type or property merging is defined.

      Default implementation returns null to allow explicit per-type or per-property attempts.

      Overrides:
      supportsUpdate in class JsonDeserializer<T>

    • convertValue

      protected T convertValue(Object delegateValue)
      Method called to convert from "delegate value" (which was deserialized from JSON using standard Jackson deserializer for delegate type) into desired target type.

      The default implementation uses configured Converter to do conversion.

      Parameters:
      delegateValue -
      Returns:
      Result of conversion

    • _convertIfNonNull

      protected T _convertIfNonNull(Object delegateValue)