[squeak-dev] some quick and dirty sites

Colin Putney colin at wiresong.com
Fri Sep 7 18:06:45 UTC 2012

On Tue, Sep 4, 2012 at 12:35 PM, Chris Cunnington
<smalltalktelevision at gmail.com> wrote:
> This is quite a
> useful demo for me to better understand Altitude and the Strategy pattern. I
> can see now that people are supposed to write locator classes as subclasses
> of ALAbstractLocator as needed, which is what the blog post shows. Once I
> saw what was supposed to happen it was simple to change it to work with the
> latest version of Altitude.

Hi guys,

I'm a little late to respond here, as I've been on vacation. :-)

I've gone back and forth on this a couple of times. The first
iteration had multiple Locator classes, but I didn't bother to have an
abstract superclass because only #pathForResource: and
#resourceForPath: are actually needed.

Then I came up with a away to factor out the commonality into a single
class called ALLocator, which would be customized by various
strategies. But the very first time I needed to customize the way urls
are constructed, I found the strategy patterned didn't give me the
flexibility I needed.

So now we both options. ALAbstractLocator shows what protocol locators
are expected to support. ALDigestLocator provides a default
implementation, which can be customized via strategies. In cases where
we want more customization than ALDigestLocator allows, we can create
an alternate concrete locator class.


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