com.fasterxml.jackson.databind.cfg

Class ContextAttributes

java.lang.Object

com.fasterxml.jackson.databind.cfg.ContextAttributes

Direct Known Subclasses:

ContextAttributes.Impl

public abstract class ContextAttributes
extends Object

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");

Since:

2.3

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ContextAttributes.Impl

Constructor Summary

Constructors

Constructor and Description
ContextAttributes()

Method Summary

Modifier and Type	Method and Description
abstract Object	getAttribute(Object key) Accessor for value of specified attribute
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.
abstract ContextAttributes	withoutSharedAttribute(Object key)
abstract ContextAttributes	withPerCallAttribute(Object key, Object value) Mutator used during call (via context) to set value of "non-shared" part of attribute set.
abstract ContextAttributes	withSharedAttribute(Object key, Object value) Fluent factory method for creating a new instance with an additional shared attribute.
abstract ContextAttributes	withSharedAttributes(Map<?,?> attributes) Fluent factory method for creating a new instance with specified set of shared attributes.

Methods inherited from class java.lang.Object

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

Constructor Detail

ContextAttributes

public ContextAttributes()

Method Detail

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.