Path: csiph.com!usenet.pasdenom.info!gegeweb.org!eternal-september.org!feeder.eternal-september.org!mx04.eternal-september.org!.POSTED!not-for-mail
From: Jim Janney <jjanney@shell.xmission.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: Caching with timed expiry
Date: Wed, 09 May 2012 13:14:36 -0600
Organization: objurgating the centipede
Lines: 31
Message-ID: <ydn3979kvz7.fsf@shell.xmission.com>
References: <joc4c0$2hm$1@news.albasani.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx04.eternal-september.org; posting-host="PnllQd880uOddfy6hsxHuQ"; logging-data="10824"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+e5rprHAsvkzHFAAnP8fjA"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux)
Cancel-Lock: sha1:DIt2xmVvStmOsRGh+Rd+K7PJcYA= sha1:evKBjOTNUByXhWVxbqsuufcYZNs=
Xref: csiph.com comp.lang.java.programmer:14452

Sebastian <sebastian@undisclosed.invalid> writes:

> Hello there,
>
> does anyone of a cache / map implementation in which entries
> expire after a fixed time? By which I mean that after a cnfigurable
> delay after an enzry has been caches,it is automatically removed
> from the cache and some clean-up action (perhaps event-triggred)
> can be taken.
>
> My scenario is this: A GUI client searches an LDAP server using
> the virtual list view control. The server requires all requests
> to be made over the same connection. So my middleware component
> will need to check out that connection from a pool and cache it,
> using the ASN1 cookie sent by the client as a key.
>
> Trouble is, if the client never signals that it won't request
> another page (e. g. because it crashes), I need to auto-release
> the LDAP server connection to the connection pool to prevent leakage.
> I thought that a ready-made cache with timed expiry would come in handy.
> If there is no such beast, any ideas for possible approaches?
>
> -- Sebastian

Look at subclassing java.util.LinkedHashMap and overriding the
removeEldestEntry method to check an expiration time.  The removal time
will not be precise (since it's triggered when something else is looked
up) but it may be good enough.

-- 
Jim Janney