Re: [eclipse-dev] resolve(URL) and asLocalURL()

[Jeff McAffer <Jeff_McAffer@xxxxxxxxxx>]

Minor point but want to be sure that
people understand.  The goal of the API is to try and reduce the given
URL to something more commonly known.  Traditionally an input of a
platform: URL would be converted.  All others were returned as is.
 The new runtime has a couple of new URL types (the ones you were
seeing being returned last night).  Since these fill a similar role
to the platform:/plugin URL, we are updating the behaviour to be similar.
Tom mentioned this. 

I would like to stress that Platform.resolve(URL)
is/will not be spec'd to return any particular kind of URL.  In the
future we want to be able to run with plugins in jars.  In this case
the result would likely be a jar: url.  If the plugin was on a web
server, it might be http:, etc etc.

The purpose of Platform.asLocalURL()
is to ensure that the resource indicated by the given URL is in fact available
directly on the local file system (via a file: or jar: url)  resolve()
is similar but does not actually fetch the URL.

Users of these API should consider their
usecases and choose which one makes the most sense for them.  

Jeff

Thomas Watson <tjwatson@xxxxxxxxxx>
Sent by: eclipse-dev-admin@xxxxxxxxxxx

01/19/2004 01:45 PM

Please respond to
eclipse-dev

To	eclipse-dev@xxxxxxxxxxx
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Subject	Re: [eclipse-dev] resolve(URL) and asLocalURL()

After some discussion it has been decided to revert back to the previous
behavior for resolve(URL) to return a file or jar URL.

The reason the change was done was to prepare for running plugins out of
jars instead of running out directories.  The problem is the resource
that a platform URL could reference might not be an actual file on the
filesystem.  It may reference a zipentry in a zipped up plugin.  Or
if you are trying to run plugins from a remote server then it may actually
be an http URL.  The resolve API makes no gaurantee on the type of
URL that it returns.  With that said it is a bit brutal to change
the URL type to something other than a default java supplied protocol (file,
jar, http etc).  So the behavior of resolve(URL) will be to return
a URL that uses one of the java supplied protocols.  For plugins running
out of directories this will continue to be a file URL.  But for plugins
that run out of jars this will be a jar URL.  This should allow our
current usecases of resolve(URL) to work because eclipse currently runs
out of directories so a file URL will always be returned.  But please
note that if eclipse is to ever run out of jars and you have code that
requires a file URL then you must use the asLocalURL() since this will
force a cache of the resource the platform URL references so that a proper
file URL can be created. 

Thomas Watson
Pervasive Development
Phone: 512-838-4533 Tie: 678-4533
tjwatson@xxxxxxxxxx

Dejan Glozic <dejan@xxxxxxxxxx> Sent by: eclipse-dev-admin@xxxxxxxxxxx 01/19/2004 10:46 AM Please respond to eclipse-dev

To:        eclipse-dev@xxxxxxxxxxx        cc:                Subject:        [eclipse-dev] resolve(URL) and asLocalURL()

This change is causing a lot of breakage. Can you describe the benefit
of
this breaking change that justifies the pain?

Regards,

Dejan Glozic, Ph.D.
Manager, Eclipse Development 1A
D2/R0Q/8200/MKM
IBM Canada Ltd.
Tel. 905 413-2745  T/L 969-2745
Fax. 905 413-4854

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