Re: [Php-java-bridge-users] Caching of (Java) objects (Lucene)

[<php...@li...>]

Hi,


> dedicated application. But in my case, I want to
> build an easy to
> distribute/deploy PHP component requiring only the
> minimim work of
> installing 

the memory cache is the easiest solution I can think
of. 

A file cache requires much more work, every node has
to serialize the data to java.io.tmpdir (that's the
only directory to which J2EE or SEL has write access)
and make sure that all other nodes don't update or
read the cache while one node updates the data.

If the data doesn't fit into memory or into
java.io.tmpdir, you'll need a decicated cache daemon
which listens on some port, updates its database
regularily and answers requests from the nodes. Users
could start this daemon, if they want to: java -jar
luceneCacheDaemon.jar

If a Socket(daemonPort) fails during startup of a node
you could revert to memory cache:

public class fooFactory {
  private static Foo foo;
  private static final Socket cacheDaemon;
  static {
    try { cacheDaemon = new Socket(DAEMON_PORT); }
    catch (IOException e) {/*ignore*/}
  }
  public static synchronized foo getFoo() {
    if(foo!=null) return foo;
    if(cacheDaemon!=null) 
      return foo=getFoo(cacheDaemon);
    return foo = createFoo();
  }
}


> to native code yet (but will do, curious about the
> performance with
> respect to a VM install)

Starting a native lucene .so costs about 100 to 150
ms.


Regards,
Jost Boekemeier



		
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