Java Reference
In-Depth Information
R
EFACTORED
SOLUTION
NAME
:
Read
/
Write Locks.
R
EFACTORED
SOLUTION
TYPE
:
Software.
R
EFACTORED
SOLUTION
DESCRIPTION
:
Instead of synchronizing on
methods or objects, use a read
/
write lock. As of the publishing date, Java
had not yet included a read
/
write lock, but many examples exist in litera-
ture and on the Internet.
R
OOT
CAUSES
:
Ignorance. Java does not yet include a read
/
write lock, and
information about this solution is not widely distributed.
S
YMPTOMS
,
CONSEQUENCES
:
This antipattern must usually be detected
by inspection, but occasionally a web application server can bog down
without fully using available
CPU
resources.
S
OLUTION
A
LTERNATIVES
:
A second solution for this problem is called
Copy-on-Write. This solution involves creating a copy of a cache item,
locking the copy, writing to the copy, and then deleting the original.
Readers in this scenario do not lock.
