Module tools.jackson.databind
Package tools.jackson.databind.cfg

Class ContextAttributes

java.lang.Object
tools.jackson.databind.cfg.ContextAttributes
All Implemented Interfaces:
Snapshottable<ContextAttributes>
Direct Known Subclasses:
ContextAttributes.Impl
public abstract class ContextAttributes extends Object implements Snapshottable<ContextAttributes>
Helper class used for storing and accessing per-call attributes. Storage is two-layered: at higher precedence, we have actual per-call (ObjectMapper.readValue or ObjectMapper.writeValue) attributes; and at lower precedence, default attributes that may be defined for Object readers and writers.

Note that the way mutability is implemented differs between kinds of attributes, to account for thread-safety: per-call attributes are handled assuming that instances are never shared, whereas changes to per-reader/per-writer attributes are made assuming sharing, by creating new copies instead of modifying state. This allows sharing of default values without per-call copying, but requires two-level lookup on access.

To set default attributes, use withSharedAttributes(Map) or withSharedAttribute(Object, Object), starting with "empty" instance (see getEmpty()). For example: 

   ContextAttributes attrs = ContextAttributes.getEmpty()
     .withSharedAttribute("foo", "bar")
     .withSharedAttribute("attr2", "value2");

  • Constructor Details

    • ContextAttributes

      public ContextAttributes()

  • Method Details

    • getEmpty

      public static ContextAttributes getEmpty()
      Accessor for an empty instance of ContextAttributes: usable as-is, or as a starting point for building up a set of default attributes.

    • withSharedAttribute

      public abstract ContextAttributes withSharedAttribute(Object key, Object value)
      Fluent factory method for creating a new instance with an additional shared attribute.
      Parameters:
      key - Name of the attribute to add
      value - Value of the attribute to add; may be null, in which case attribute will be removed if it already exists.
      Returns:
      New instance of ContextAttributes that has specified change.

    • withSharedAttributes

      public abstract ContextAttributes withSharedAttributes(Map<?,?> attributes)
      Fluent factory method for creating a new instance with specified set of shared attributes. Any shared attributes that already exist will be replaced
      Parameters:
      attributes - Map of shared attributes to add, replacing any existing ones.
      Returns:
      New instance of ContextAttributes that has specified shared attributes.

    • withoutSharedAttribute

      public abstract ContextAttributes withoutSharedAttribute(Object key)

    • getAttribute

      public abstract Object getAttribute(Object key)
      Accessor for value of specified attribute

    • withPerCallAttribute

      public abstract ContextAttributes withPerCallAttribute(Object key, Object value)
      Mutator used during call (via context) to set value of "non-shared" part of attribute set.