Documentation  › java.lang  › InheritableThreadLocal
 
 


  InheritableThreadLocal
  public

  Inherits From:   ThreadLocal : Object
  Conforms To:   none
  Declared In:   java.lang


Class Description
 
This class extends ThreadLocal to provide inheritance of values from parent thread to child thread: when a child thread is created, the child receives initial values for all inheritable thread-local variables for which the parent has values. Normally the child's values will be identical to the parent's; however, the child's value can be made an arbitrary function of the parent's by overriding the childValue method in this class.

Inheritable thread-local variables are used in preference to ordinary thread-local variables when the per-thread-attribute being maintained in the variable (e.g., User ID, Transaction ID) must be automatically transmitted to any child threads that are created.



Class Variables
 
None declared in this class.


Instance Variables
 
None declared in this class.


Constructors
 
InheritableThreadLocal
public InheritableThreadLocal( )

No description available for this constructor.


Class Methods
 
None declared in this class.


Instance Methods
 
childValue
protected Object childValue( Object parentValue )

Computes the child's initial value for this inheritable thread-local variable as a function of the parent's value at the time the child thread is created. This method is called from within the parent thread before the child is started.

This method merely returns its input argument, and should be overridden if a different behavior is desired.



Known Subclasses
 
None.



 
 
  dydoc
  3/10/05