Proposal: Pluggable Lock Framework for Lucene
Date: Nov 2004
Developer: Jeff Patterson (jeffATwebdoyen.com -
http://www.webdoyen.com
)
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Abstract: A framework to allow Lucene users to override the default
FileSystem locking mechanism with a custom lock mechanism.
A Lucene user may develop a new class that extends
org.apache.lucene.store.Lock and implement bodies for the following
methods:
public boolean obtain() - to obtain custom lock
public boolean isLocked() - to detect custom lock
public void release() - to release custom lock
NOTE: When implementing these methods, the developer should make sure to
use the this.getLockName() method on the Lock to identify which lock
is being manipulated (see Modified Files below for more).
After developed, the new class must be added to the classpath (along
with any other supporting classes/libraries needed by the new class),
and the Lucene framework must be alerted of the new class by way of
the "org.apache.lucene.lockClass" -D System property. Example:
java -Dorg.apache.lucene.lockClass=foo.MyCustomLocker LuceneTest
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Modified Files: The following files were modified to support
this framework (DIFF files at end):
- org.apache.lucene.store.Lock
The member "lockName" and an accompanying protected getter and
setter were added to this class to support naming the lock. This
is transparent to the default lock mechanism and is only useful
when writing a custom lock.
- org.apache.lucene.store.FSDirectory
Instead of instantiating a default Lock, this class now checks
to see if an overridden Lock mechanism is provided, and if so
asks the LockFactory (see below) to provide an overridden Lock
class.
New Files: The following files were added to support this framework:
- org.apache.lucene.store.LockFactory
This class is used to reflect and instantiate by name the custom
Lock implementation. Error handing should be modified in this
class, but that would have required a more extensive code overhaul.
The javadocs for the LockFactory contain a skeleton Java file for
a custom lock implementation.
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Improvement
Closed
Minor
[PATCH] Lock Framework - allows custom lock mechanism
