Re: [Fwd: Re: Mailet API]
I think I've sent around my thoughts on this, but here goes anyway. a) I would like at some point to change the mailet API to have object attributes on the Mail object (e.g., add getAttribute(String name), setAttribute(String name, Object value), remoteAttribute(String name)). This would let you pass information between matchers and mailets, and mailets and mailets for that matter. b) the CommandForListserv/AvalonListservManager is a bad design pattern IMHO (although I did write it). Matchers are supposed to be convenient ways to component-ize functionality you might want to use in multiple mail apps. Checking the remote IP address, looking up a blacklist via DNS, checking a header, etc... these are great checks that anybody could use, and make great matchers. I think if you're doing something so functionally-specific as CommandForListserv does, you should just use the All matcher and have the Mailet do all the work. There's nothing a matcher can do that a mailet can't, and I don't think we need to change the API to make mailets have a default... I think this makes the API more complicated without simplifying configuration in most cases. I mean to write a decent listserv soon and will likely squash/deprecate the command for listserv matcher since it is a bad example, IMHO. -- Serge Knystautas Loki Technologies - Unstoppable Websites http://www.lokitech.com/ Jeff Keyser wrote: I agree that the work of matching and doing something should be separate. However, I'd like to suggest an alternative way of communicating, since it may be helpful for a Mailet to know what parameters were user by the Matcher. I'm thinking specifically about the CommandForListserv Matcher and the AvalonListservManager Mailet. It would probably be helpful for the Mailet to explicitly know which mailing list it is processing for. It may also be helpful to know which command was matched, but that's getting even more complicated. How to do this? I'm not sure, but if it can be done cleanly, I see it being useful. -Original Message- From: Andrew Timberlake [mailto:[EMAIL PROTECTED]] Sent: Monday, April 22, 2002 12:00 PM To: [EMAIL PROTECTED] Subject: [Fwd: Re: Mailet API] Thanks Dave for the response I'm forwarding this thread back into the list as I would like to hear the main developers, and others, feedback and insight into this. Thanks Andrew -Forwarded Message- From: Dave Morris [EMAIL PROTECTED] To: Andrew Timberlake [EMAIL PROTECTED] Subject: Re: Mailet API Date: 22 Apr 2002 16:19:22 +0100 Yep. Quite true. However, kind of makes the Matcher redundant if all the Mailets start doing their own matching. I kind of like the separation of functionality, a Matcher filters the messages and a Mailet does stuff with the messages. What I want to add is a way of the Mailet an Matcher to talk to each other, mainly to share configuration information. This came up when I was experimenting with designing some of my own custom Mailets. In each case, the Mailet needed to process emails to one or more addresses in a list or group. Both the Mailet and Matcher needed to be configured to access the same list of addresses. I kept ending up with an odd situation where both the Mailet and Matcher share the same list of addresses, but they can't communicate directly with each other. Much like the current RecipientIsLocal Matcher and LocalDeliver Mailet, both have to use an Avalon lookup to get a reference to the local reporistory, but they can't talk to each other. You are right, it is possible to implement using the current API, just a few extra hoops to jump through. The proposed change would just make it a little easier to design Matcher and Mailet combinations. If it causes too many side effects, then it isn't worth it. Thanks, Dave Andrew Timberlake wrote: Just a quick question. A mailet can perform the function of a matcher just by virtue of checking the mail message as it processes it. Therefore could you not achieve what you are looking for with the match=ALL and then write matching information into the mailet? Andrew On Mon, 2002-04-22 at 14:21, Dave Morris wrote: Hi, I would like to propose a change to the Mailet API, and would be interested in thoughts and ideas. At the moment, Mailets have no access to their Matcher. I appreciate that this is probably by design. However . I would like to suggest adding the following to the Mailet API. /** * Create a Matcher for this Mailet. * Default is to return null and let the container create the Matcher. * Advantage is that the Mailet can use it's internal data to generate and configure a suitable Matcher. * Disadvantage is that the Mailet interface becomes tied to the Matcher interface. * */ public Matcher getMatcher() ; And changing the code which loads the Mailets and Matchers in JamesSpoolManager to this. Mailet mailet = null; Matcher matcher = null;
RE: [Fwd: Re: Mailet API]
For consideration: c) allow mailets (and matchers?) to log messages at levels other than info, i.e. debug, warn, error, fatal etc. Cheers Steve -Original Message- From: Serge Knystautas [mailto:[EMAIL PROTECTED]] Sent: Tuesday, April 30, 2002 12:46 PM To: James Developers List Subject: Re: [Fwd: Re: Mailet API] I think I've sent around my thoughts on this, but here goes anyway. a) I would like at some point to change the mailet API to have object attributes on the Mail object (e.g., add getAttribute(String name), setAttribute(String name, Object value), remoteAttribute(String name)). This would let you pass information between matchers and mailets, and mailets and mailets for that matter. b) the CommandForListserv/AvalonListservManager is a bad design pattern IMHO (although I did write it). Matchers are supposed to be convenient ways to component-ize functionality you might want to use in multiple mail apps. Checking the remote IP address, looking up a blacklist via DNS, checking a header, etc... these are great checks that anybody could use, and make great matchers. I think if you're doing something so functionally-specific as CommandForListserv does, you should just use the All matcher and have the Mailet do all the work. There's nothing a matcher can do that a mailet can't, and I don't think we need to change the API to make mailets have a default... I think this makes the API more complicated without simplifying configuration in most cases. I mean to write a decent listserv soon and will likely squash/deprecate the command for listserv matcher since it is a bad example, IMHO. -- Serge Knystautas Loki Technologies - Unstoppable Websites http://www.lokitech.com/ Jeff Keyser wrote: I agree that the work of matching and doing something should be separate. However, I'd like to suggest an alternative way of communicating, since it may be helpful for a Mailet to know what parameters were user by the Matcher. I'm thinking specifically about the CommandForListserv Matcher and the AvalonListservManager Mailet. It would probably be helpful for the Mailet to explicitly know which mailing list it is processing for. It may also be helpful to know which command was matched, but that's getting even more complicated. How to do this? I'm not sure, but if it can be done cleanly, I see it being useful. -Original Message- From: Andrew Timberlake [mailto:[EMAIL PROTECTED]] Sent: Monday, April 22, 2002 12:00 PM To: [EMAIL PROTECTED] Subject: [Fwd: Re: Mailet API] Thanks Dave for the response I'm forwarding this thread back into the list as I would like to hear the main developers, and others, feedback and insight into this. Thanks Andrew -Forwarded Message- From: Dave Morris [EMAIL PROTECTED] To: Andrew Timberlake [EMAIL PROTECTED] Subject: Re: Mailet API Date: 22 Apr 2002 16:19:22 +0100 Yep. Quite true. However, kind of makes the Matcher redundant if all the Mailets start doing their own matching. I kind of like the separation of functionality, a Matcher filters the messages and a Mailet does stuff with the messages. What I want to add is a way of the Mailet an Matcher to talk to each other, mainly to share configuration information. This came up when I was experimenting with designing some of my own custom Mailets. In each case, the Mailet needed to process emails to one or more addresses in a list or group. Both the Mailet and Matcher needed to be configured to access the same list of addresses. I kept ending up with an odd situation where both the Mailet and Matcher share the same list of addresses, but they can't communicate directly with each other. Much like the current RecipientIsLocal Matcher and LocalDeliver Mailet, both have to use an Avalon lookup to get a reference to the local reporistory, but they can't talk to each other. You are right, it is possible to implement using the current API, just a few extra hoops to jump through. The proposed change would just make it a little easier to design Matcher and Mailet combinations. If it causes too many side effects, then it isn't worth it. Thanks, Dave Andrew Timberlake wrote: Just a quick question. A mailet can perform the function of a matcher just by virtue of checking the mail message as it processes it. Therefore could you not achieve what you are looking for with the match=ALL and then write matching information into the mailet? Andrew On Mon, 2002-04-22 at 14:21, Dave Morris wrote: Hi, I would like to propose a change to the Mailet API, and would be interested in thoughts and ideas. At the moment, Mailets have no access to their Matcher. I appreciate that this is probably by design. However . I would like to suggest adding the following to the Mailet API. /** * Create a Matcher for this Mailet. * Default is to return null and let the container create the Matcher. * Advantage is that the Mailet can use it's internal data
Re: [Fwd: Re: Mailet API]
Ah, very interesting. Seems very reasonable to me. +1. I would like to make one more near-final release of James (with proper avalon releases and any additional few bug fixes) before we start changing the mailet API. -- Serge Knystautas Loki Technologies - Unstoppable Websites http://www.lokitech.com/ Steve Short wrote: For consideration: c) allow mailets (and matchers?) to log messages at levels other than info, i.e. debug, warn, error, fatal etc. Cheers Steve -Original Message- From: Serge Knystautas [mailto:[EMAIL PROTECTED]] Sent: Tuesday, April 30, 2002 12:46 PM To: James Developers List Subject: Re: [Fwd: Re: Mailet API] I think I've sent around my thoughts on this, but here goes anyway. a) I would like at some point to change the mailet API to have object attributes on the Mail object (e.g., add getAttribute(String name), setAttribute(String name, Object value), remoteAttribute(String name)). This would let you pass information between matchers and mailets, and mailets and mailets for that matter. b) the CommandForListserv/AvalonListservManager is a bad design pattern IMHO (although I did write it). Matchers are supposed to be convenient ways to component-ize functionality you might want to use in multiple mail apps. Checking the remote IP address, looking up a blacklist via DNS, checking a header, etc... these are great checks that anybody could use, and make great matchers. I think if you're doing something so functionally-specific as CommandForListserv does, you should just use the All matcher and have the Mailet do all the work. There's nothing a matcher can do that a mailet can't, and I don't think we need to change the API to make mailets have a default... I think this makes the API more complicated without simplifying configuration in most cases. I mean to write a decent listserv soon and will likely squash/deprecate the command for listserv matcher since it is a bad example, IMHO. -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Re: [Fwd: Re: Mailet API]
Jeff,
It would probably be helpful for the Mailet to explicitly know which mailing
list it is processing for.
It may also be helpful to know which command was matched, but that's getting
even more complicated.
This is the kind of thing I as trying to do.
With the minimum changes to the current API, which is why I came up with the
idea of allowing the Mailet to create the Matcher.
In the example you describe.
The list name could be moved into the Mailet configuration rather than the
Matcher configuration.
mailet class=AvalonListservManager
listName[EMAIL PROTECTED]/listName
repositoryNamejames-list/repositoryName
/mailet
The Mailet gets the list name by reading the configuration when it is
initialised.
The Mailet then creates the Matcher, passing it the same list name.
/**
* Our Matcher.
*
*/
private Matcher matcher ;
/**
* Initialise our Matcher, using the list name from our config.
*
*/
protected void initMatcher()
throws MessagingException
{
//
// Create our Matcher.
//
matcher = new CommandForListserv() ;
MatcherConfigImpl config = new MatcherConfigImpl();
//
// Set the Matcher list name.
//
config.setCondition(myListname);
config.setMailetContext(getMailetContext());
matcher.init(config);
}
/**
* Get our Matcher, creating a new one if required.
*
*/
public Matcher getMatcher()
{
if (null == matcher)
{
initMatcher() ;
}
return matcher ;
}
So, both the Mailet and the Matcher get the same list name, set once in the
Mailet configuration.
If you want to add additional communication between the Matcher and Mailet.
To be able to change the list name for example (not a very practical example,
but just suppose).
You could extend the Matcher class, to add setListName() and getListName()
methods.
class XCommandForListserv
extends CommandForListserv
{
public void setListName(String name) { } ;
public String getListName() { } ;
}
The Mailet could then create an XCommandForListserv, and have access to the new
methods.
Internally, the Mailet has a reference to the extended class, but externally it
is still a generic Matcher.
/**
* Our extended Matcher.
*
*/
private XCommandForListserv matcher ;
/**
* Initialise our Matcher, using the list name from our config.
*
*/
protected void initMatcher()
throws MessagingException
{
//
// Create our extended Matcher.
//
matcher = new XCommandForListserv() ;
MatcherConfigImpl config = new MatcherConfigImpl();
//
// Set the Matcher list name.
//
config.setCondition(myListname);
config.setMailetContext(getMailetContext());
matcher.init(config);
}
/**
* Get our Matcher, creating a new one if required.
*
*/
public Matcher getMatcher()
{
if (null == matcher)
{
initMatcher() ;
}
return matcher ;
}
/**
* Change the list name for no obvious reason.
*
*/
public void sillyExample(String name)
{
if (null != matcher)
{
matcher.setListName(name) ;
}
}
Would this enable you to do what you wanted ?
Hopefully, without too many side effects on the rest of the Mailet / Matcher
code already in place.
In theory, it would be possible to extend XCommandForListserv to enable the
Mailet to ask the Matcher what command was matched.
However, it would probably need to be thread safe and sync possible, but a
bit more complicated.
Hope this helps,
Dave
Jeff Keyser wrote:
I agree that the work of matching and doing something should be separate.
However, I'd like to suggest an alternative way of communicating, since it
may be helpful for a Mailet to know what parameters were user by the
Matcher.
I'm thinking specifically about the CommandForListserv Matcher and the
AvalonListservManager Mailet. It would probably be helpful for the Mailet
to explicitly know which mailing list it is processing for. It may also be
helpful to know which command was matched, but that's getting even more
complicated.
How to do this? I'm not sure, but if it can be done cleanly, I see it being
useful.
-Original Message-
From: Andrew Timberlake [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 22, 2002 12:00 PM
To: [EMAIL PROTECTED]
Subject: [Fwd: Re: Mailet API]
Thanks Dave for the response
I'm forwarding this thread back into the list as I would like to hear
the main developers, and others, feedback and insight into this.
Thanks
Andrew
-Forwarded Message-
From: Dave Morris [EMAIL PROTECTED]
To: Andrew Timberlake [EMAIL PROTECTED]
Subject: Re: Mailet API
Date: 22 Apr 2002 16:19:22
RE: [Fwd: Re: Mailet API]
I agree that the work of matching and doing something should be separate.
However, I'd like to suggest an alternative way of communicating, since it
may be helpful for a Mailet to know what parameters were user by the
Matcher.
I'm thinking specifically about the CommandForListserv Matcher and the
AvalonListservManager Mailet. It would probably be helpful for the Mailet
to explicitly know which mailing list it is processing for. It may also be
helpful to know which command was matched, but that's getting even more
complicated.
How to do this? I'm not sure, but if it can be done cleanly, I see it being
useful.
-Original Message-
From: Andrew Timberlake [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 22, 2002 12:00 PM
To: [EMAIL PROTECTED]
Subject: [Fwd: Re: Mailet API]
Thanks Dave for the response
I'm forwarding this thread back into the list as I would like to hear
the main developers, and others, feedback and insight into this.
Thanks
Andrew
-Forwarded Message-
From: Dave Morris [EMAIL PROTECTED]
To: Andrew Timberlake [EMAIL PROTECTED]
Subject: Re: Mailet API
Date: 22 Apr 2002 16:19:22 +0100
Yep.
Quite true.
However, kind of makes the Matcher redundant if all the
Mailets start doing their
own matching.
I kind of like the separation of functionality, a Matcher
filters the messages
and a Mailet does stuff with the messages. What I want to add
is a way of the
Mailet an Matcher to talk to each other, mainly to share configuration
information.
This came up when I was experimenting with designing some of
my own custom
Mailets.
In each case, the Mailet needed to process emails to one or
more addresses in a
list or group.
Both the Mailet and Matcher needed to be configured to access
the same list of
addresses.
I kept ending up with an odd situation where both the Mailet
and Matcher share
the same list of addresses, but they can't communicate
directly with each other.
Much like the current RecipientIsLocal Matcher and
LocalDeliver Mailet, both have
to use an Avalon lookup to get a reference to the local
reporistory, but they
can't talk to each other.
You are right, it is possible to implement using the current
API, just a few
extra hoops to jump through.
The proposed change would just make it a little easier to
design Matcher and
Mailet combinations.
If it causes too many side effects, then it isn't worth it.
Thanks,
Dave
Andrew Timberlake wrote:
Just a quick question.
A mailet can perform the function of a matcher just by virtue of
checking the mail message as it processes it. Therefore
could you not
achieve what you are looking for with the match=ALL and then write
matching information into the mailet?
Andrew
On Mon, 2002-04-22 at 14:21, Dave Morris wrote:
Hi,
I would like to propose a change to the Mailet API, and would be
interested in thoughts and ideas.
At the moment, Mailets have no access to their Matcher.
I appreciate that this is probably by design.
However . I would like to suggest adding the
following to the Mailet
API.
/**
* Create a Matcher for this Mailet.
* Default is to return null and let the container create the
Matcher.
* Advantage is that the Mailet can use it's internal data to
generate and configure a suitable Matcher.
* Disadvantage is that the Mailet interface becomes
tied to the
Matcher interface.
*
*/
public Matcher getMatcher() ;
And changing the code which loads the Mailets and Matchers in
JamesSpoolManager to this.
Mailet mailet = null;
Matcher matcher = null;
//
// Allow blank 'match' attribute in config XML.
String matcherName = c.getAttribute(match, null);
//
// Load the Mailet.
mailet = loadMailet(mailetClassName, mailetcontext, c) ;
//
// If the config specified a Matcher.
if (null != matcherName)
{
matcher = loadMatcher(matcherName, mailetcontext) ;
}
//
// If not, see if the Mailet has it's own Matcher.
else {
matcher = mailet.getMatcher() ;
}
//
// If we still don't have a Matcher.
if (null == matcher)
{
//
// Two possible options.
// a) Throw an Exception saying No Matcher specified
for Mailet.
// b) Add a default 'All' Matcher.
// Depends which people think makes more sense
//
}
This does not break any of the existing Maliets or configuration.
All of the existing mailets can implement the new method
and return
null, leaving the container to configure the Matcher.
All of the exisiting configuration stays the same, any
Matcher specified
in the config will override the Matcher generated by a new Mailet.
As an example of what this change would gain, consider the local
delivery
