org.springframework.core

Interface AttributeAccessor

All Known Subinterfaces:

AnnotatedBeanDefinition, BeanDefinition, TestContext

All Known Implementing Classes:

AbstractBeanDefinition, AnnotatedGenericBeanDefinition, AttributeAccessorSupport, AutowireCandidateQualifier, BeanMetadataAttributeAccessor, ChildBeanDefinition, DefaultTestContext, GenericBeanDefinition, PropertyValue, RootBeanDefinition, ScannedGenericBeanDefinition

public interface AttributeAccessor

Interface defining a generic contract for attaching and accessing metadata to/from arbitrary objects.

Since:

2.0

Author:

Rob Harrop, Sam Brannen

Method Summary

Modifier and Type	Method and Description
String[]	attributeNames() Return the names of all attributes.
default <T> T	computeAttribute(String name, Function<String,T> computeFunction) Compute a new value for the attribute identified by name if necessary and set the new value in this AttributeAccessor.
Object	getAttribute(String name) Get the value of the attribute identified by name.
boolean	hasAttribute(String name) Return true if the attribute identified by name exists.
Object	removeAttribute(String name) Remove the attribute identified by name and return its value.
void	setAttribute(String name, Object value) Set the attribute defined by name to the supplied value.

Method Detail

setAttribute

void setAttribute(String name,
                  @Nullable
                  Object value)

Set the attribute defined by name to the supplied value.

If value is null, the attribute is removed.

In general, users should take care to prevent overlaps with other metadata attributes by using fully-qualified names, perhaps using class or package names as prefix.

Parameters:

name - the unique attribute key

value - the attribute value to be attached

getAttribute

@Nullable
Object getAttribute(String name)

Get the value of the attribute identified by name.

Return null if the attribute doesn't exist.

Parameters:

name - the unique attribute key

Returns:

the current value of the attribute, if any

computeAttribute

default <T> T computeAttribute(String name,
                               Function<String,T> computeFunction)

Compute a new value for the attribute identified by name if necessary and set the new value in this AttributeAccessor.

If a value for the attribute identified by name already exists in this AttributeAccessor, the existing value will be returned without applying the supplied compute function.

The default implementation of this method is not thread safe but can overridden by concrete implementations of this interface.

Type Parameters:

T - the type of the attribute value

Parameters:

name - the unique attribute key

computeFunction - a function that computes a new value for the attribute name; the function must not return a null value

Returns:

the existing value or newly computed value for the named attribute

Since:

5.3.3

See Also:

getAttribute(String), setAttribute(String, Object)

removeAttribute

@Nullable
Object removeAttribute(String name)

Remove the attribute identified by name and return its value.

Return null if no attribute under name is found.

Parameters:

name - the unique attribute key

Returns:

the last value of the attribute, if any

hasAttribute

boolean hasAttribute(String name)

Return true if the attribute identified by name exists.

Otherwise return false.

Parameters:

name - the unique attribute key

attributeNames

String[] attributeNames()

Return the names of all attributes.