| 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. |
