Thread: [Springframework-developer] Custom bean instantiation language?

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springframework-developer

[Springframework-developer] Custom bean instantiation language?

From: Paul G. <pa...@pa...> - 2005-02-19 19:24:17

A quick search didn't turn up anything in the archive...has anyone given 
serious thought to a custom language to replace the XML bean 
instantiation definitions that seem to be the current standard?

Re: [Springframework-developer] Custom bean instantiation language?

From: jbetancourt <jbe...@co...> - 2005-02-19 20:47:42

There is support for scripting.  I think it is part of the sandbox.  Thus,
you can use Beanshell, Groovy, etc.

But, not sure if this is meant as a 'custom language' for bean
instantiation.


----- Original Message ----- 
From: "Paul Galbraith" <pa...@pa...>
To: <spr...@li...>
Sent: Saturday, February 19, 2005 2:23 PM
Subject: [Springframework-developer] Custom bean instantiation language?


> A quick search didn't turn up anything in the archive...has anyone given
> serious thought to a custom language to replace the XML bean
> instantiation definitions that seem to be the current standard?
>
>
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Re: [Springframework-developer] Custom bean instantiation language?

From: Paul G. <pa...@pa...> - 2005-02-20 04:11:03

jbetancourt wrote:

>There is support for scripting.  I think it is part of the sandbox.  Thus,
>you can use Beanshell, Groovy, etc.
>
>But, not sure if this is meant as a 'custom language' for bean
>instantiation.
>
>  
>
That might do the trick...can I use a groovy script to wire up my bean 
factories?

>----- Original Message ----- 
>From: "Paul Galbraith" <pa...@pa...>
>To: <spr...@li...>
>Sent: Saturday, February 19, 2005 2:23 PM
>Subject: [Springframework-developer] Custom bean instantiation language?
>
>
>  
>
>>A quick search didn't turn up anything in the archive...has anyone given
>>serious thought to a custom language to replace the XML bean
>>instantiation definitions that seem to be the current standard?
>>
>>
>>-------------------------------------------------------
>>SF email is sponsored by - The IT Product Guide
>>Read honest & candid reviews on hundreds of IT Products from real users.
>>Discover which products truly live up to the hype. Start reading now.
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>>_______________________________________________
>>Springframework-developer mailing list
>>Spr...@li...
>>https://lists.sourceforge.net/lists/listinfo/springframework-developer
>>
>>    
>>
>
>
>
>
>-------------------------------------------------------
>SF email is sponsored by - The IT Product Guide
>Read honest & candid reviews on hundreds of IT Products from real users.
>Discover which products truly live up to the hype. Start reading now.
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>https://lists.sourceforge.net/lists/listinfo/springframework-developer
>  
>

Re: [Springframework-developer] Custom bean instantiation language?

From: Paul G. <pa...@pa...> - 2005-02-20 17:41:57

Paul Galbraith wrote:

> jbetancourt wrote:
>
>> There is support for scripting.  I think it is part of the sandbox.  
>> Thus,
>> you can use Beanshell, Groovy, etc.
>>
>> But, not sure if this is meant as a 'custom language' for bean
>> instantiation.
>>
>>  
>>
> That might do the trick...can I use a groovy script to wire up my bean 
> factories?
>
After thinking about this, I doubt scripting is what I'm interested 
in...I imagine that any creation of a BeanFactory through a scripting 
engine is still ultimately using the documented core Spring API?

I'm more interested in something declarative, such as the XML 
declarations that are documented in the online reference...my motivation 
for raising the idea is simply that XML isn't a great language to use 
for interfacing with people.  I was thinking of something more 
java-like, such as a bean definition like:

singleton my.package.MyClass my.beannamespace.myBean 
(my.beannamespace.myBean2) {
        property String stringProperty "string-property";
        property my.pacakge.myClass3 my.beannamespace.myBean3;
}

Obviously I haven't put a whole lot of thought into it...just wondering 
if the same thing's already been discussed or considered?

Re: [Springframework-developer] Custom bean instantiation language?

From: Jean-Philippe G. <ga...@ya...> - 2005-02-21 02:29:39

(This is an opportunity for me to share my thoughts about the bean factory.)

I think the current XML syntax for the BeanFactory is very verbose.  Two years
ago, I developed my own BeanFactory based on Rod Johnson's initial
XmlBeanFactory (before Spring was born).  I'm still using this customized
BeanFactory today.  First thing I did was to remove extra XML elements that
were always implied by the context (like '<bean>' and '<property>').

So instead of...
<bean name="myBean" class="myclass">
  <property name="myProperty>value</property>
</bean>

...I only need...
<myBean class="myclass">
  <myProperty>value</myProperty>
</myBean>

This is more readable and much more terse.  The price to pay for that: I cannot
have XML grammar validation (such as DTD or Schema) but I see little value in
that (at least, for my own needs).  My XML editor can still find errors if my
document is not well-formed.

The second step I took was to add a special syntax for bean references (using
the @ symbol:

So...
<bean name="beanA" class="ClassA"/>

<bean name="beanB" class="ClassB">
 <property name="otherBean" beanRef="true">beanA</property>
</bean>

...can be expressed simply as...

<beanA class="ClassA"/>

<beanB class="ClassB">
  <otherBean>@beanA</otherBean>
</beanB>

I've added other lightweight syntaxes for lists and maps.

The third major change I did was to allow bean definitions to be overridden by
values specified in other files.  In Spring, you would use the
PropertyResourceConfigurer instead to resolve similar (but not all) problems.  

For instance, I have the following 3 files:

========base-config.xml (base configuration for the prod):
<beans>
  <logger class="com.xyz.Logger">
    <file>/var/log/app/log.txt</file>
    <level>ERROR</level>
  </logger>

  <messageMailer class="com.xyz.Mailer">
    <smtpHostname>mail.xyz.com</smtpHostName>
    <address>ab...@xy...</address>
  </messageMailer>
</beans>

========development-environment.xml (overidding for all the developers):
<beans>
  <logger>
    <level>INFO</level>
  </logger>
</beans>

========user.xml (developer specific overriding file):
<beans>
  <mailer>
    <address>us...@xy...</address>
  </mailer>
</beans>

I create the BeanFactory using the 3 files:

//not very accurate but you can get the idea...
BeanDefinitionContainer container = new BeanDefinitionContainer();
container.add(new XmlBeanDefinitionSource("base-config.xml"));
container.add(new XmlBeanDefinitionSource("development-environment.xml"));
container.add(new XmlBeanDefinitionSource("user.xml"));
BeanFactory factory = new BeanFactory(container);

The bean factory (the definition container, in fact) will read the 3 files and
merge property definitions specified in each files.  This is very handy when
you need to have multiple levels of configuration.  This lets you assemble
configurations in a very flexible manner.  I think this is interesting because
an "override file" shares the same syntax (and power) as a regular bean
definition file.

The key to a "custom bean instantiation language" is to keep bean definitions
separated from the BeanFactory.  Currently, in Spring,
DefaultListableBeanFactory plays both roles (it's a BeanFactory and a
BeanDefinitionRegistry).  Although both interfaces exists in the framework,
they are not used separately.

Having a definition container (or registry) allows the modification of the bean
definitions before they are used by the bean factory.  For example, I have a
CommandLineBeanDefinitionOverride class that modifies bean definition based on
command-line arguments.  

public class MyMain
{
  public static void main(String[] args)
  {
    BeanDefinitionContainer container = new BeanDefinitionContainer();
    container.add(new XmlBeanDefinitionSource("base-config.xml"));
    container.add(new XmlBeanDefinitionSource("development-environment.xml"));
    container.add(new XmlBeanDefinitionSource("user.xml"));

    args = CommandLineBeanDefinitionOverride.processArguments(args, container);
    BeanFactory factory = new BeanFactory(container); 
    ...
  }
}

I can invoke my java app and change bean values:

$java MyTest --logger +level=DEBUG

I use "--" to specify bean name and "+" to specify property name.  This opens
up bean definitions customization beyond XML configuration file.

I'm not totally familiar with the Spring framework and maybe it's already
possible to do everything I've explained above.  I just wanted to talk about my
experience about the subject.

Jean-Philippe

--- Paul Galbraith <pa...@pa...> wrote:
> Paul Galbraith wrote:
> 
> > jbetancourt wrote:
> >
> >> There is support for scripting.  I think it is part of the sandbox.  
> >> Thus,
> >> you can use Beanshell, Groovy, etc.
> >>
> >> But, not sure if this is meant as a 'custom language' for bean
> >> instantiation.
> >>
> >>  
> >>
> > That might do the trick...can I use a groovy script to wire up my bean 
> > factories?
> >
> After thinking about this, I doubt scripting is what I'm interested 
> in...I imagine that any creation of a BeanFactory through a scripting 
> engine is still ultimately using the documented core Spring API?
> 
> I'm more interested in something declarative, such as the XML 
> declarations that are documented in the online reference...my motivation 
> for raising the idea is simply that XML isn't a great language to use 
> for interfacing with people.  I was thinking of something more 
> java-like, such as a bean definition like:
> 
> singleton my.package.MyClass my.beannamespace.myBean 
> (my.beannamespace.myBean2) {
>         property String stringProperty "string-property";
>         property my.pacakge.myClass3 my.beannamespace.myBean3;
> }
> 
> Obviously I haven't put a whole lot of thought into it...just wondering 
> if the same thing's already been discussed or considered?
> 
> 
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
> http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> _______________________________________________
> Springframework-developer mailing list
> Spr...@li...
> https://lists.sourceforge.net/lists/listinfo/springframework-developer
> 

=====
---------------------------------------
Jean-Philippe Gariépy (ga...@ya...)

"Quand l'appétit va, tout va." 
                       -Obélix

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RE: [Springframework-developer] Custom bean instantiation language?

From: Cameron B. <ca...@br...> - 2005-02-21 02:38:49

> -----Original Message-----
> From: spr...@li...
> [mailto:spr...@li...] On Behalf
> Of Jean-Philippe Gariepy
> Sent: Monday, 21 February 2005 12:29 PM
> To: spr...@li...
> Subject: Re: [Springframework-developer] Custom bean instantiation
> language?
> 
> (This is an opportunity for me to share my thoughts about the bean
> factory.)

--SNIP--

> I've added other lightweight syntaxes for lists and maps.
> 

Can you please share them too. I like the look of this :)


Thanks,

Cameron

RE: [Springframework-developer] Custom bean instantiation language?

From: Jean-Philippe G. <ga...@ya...> - 2005-02-21 15:47:37

I choose the { and } characters for the lists and [ ] for the maps.

So instead of...

<bean id="myBean" class="example.MyClass">
  <property name="someList">
    <list>
      <value>item value</value>
      <ref bean="beanReference"/>
    </list>    
  </property>

  <property name="someMap">
    <map>
      <entry key="key1">
        <value>value1</value>
      </entry>
      <entry key="key2">
        <value>value2</value>
      </entry>
    </map>
  </property>
</bean>

...I have...

<myBean class="example.MyClass">
  <someList>{item value, @beanReference}</someList>
  <someMap>[key1=value1, key2=value2]</someMap>
</myBean>

Note that I've allowed bean references to be keys.  Hence, the following is
legal:

<myBean class="example.MyClass">
  <someList>{item value, @beanReference}</someList>
  <someMap>[@beanReference=value1, key2=value2]</someMap>
</myBean>

Of course, when a meta-character (@ , [ ] { } =) is part of the key or value,
an escape character is required:

<myBean class="example.MyClass">
  <emailAddresses>{user1\@domain1.com, user2\@domain2.com}</emailAddresses>
</myBean>

Jean-Philippe

--- Cameron Braid <ca...@br...> wrote:
 
> > -----Original Message-----
> > From: spr...@li...
> > [mailto:spr...@li...] On Behalf
> > Of Jean-Philippe Gariepy
> > Sent: Monday, 21 February 2005 12:29 PM
> > To: spr...@li...
> > Subject: Re: [Springframework-developer] Custom bean instantiation
> > language?
> > 
> > (This is an opportunity for me to share my thoughts about the bean
> > factory.)
> 
> --SNIP--
> 
> > I've added other lightweight syntaxes for lists and maps.
> > 
> 
> Can you please share them too. I like the look of this :)
> 
> 
> Thanks,
> 
> Cameron
> 


=====
---------------------------------------
Jean-Philippe Gariépy (ga...@ya...)

"Quand l'appétit va, tout va." 
                       -Obélix


		
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[Springframework-developer] Adding Contribution support

From: Martin K. <Mar...@St...> - 2005-02-21 20:13:18

Hi developers,

   I am still dreaming about Spring supporting contributions
right out of the box. I posted an article in the architectural section
of the forum. I guess I found a quite good and sound implementation.

This is the short form:

1. new contribution tag features the same things bean also does.

<contribution extension-point="extensionPoint id" class="MyClass">
   same as bean
</contribution>

2. A extension point is constructed by the application hosting it.
type ExtensionPoint {
   //nothing just for identification
   //maybe hidden storing of the extension point id for semantic equal 
checking
}

3. Add support to the ApplicationContext for pulling the contributions

Object [] successfullInstanciatedContributions=
    ApplicationContext.instanciateContributions(ExtensionPoint, 
ExtensionPointPolicy);

4. ExtensionPointPolicy is about finishing the init process of a 
contribution
since some not hardwired dependencies have to be set by the stakeholder
of the contribution and can not be described within the contribution 
definition.

type ExtensionPointPolicy {
    boolean isCompatibleContribution(ContributionDefinition);
    injectAdditionalDependecies(Object contributionInstance);
}

So loading contributed toolbar actions may look like this:
MyApplication.loadToolBarActions{
     Object [] toolBarActions=
         applicationContext.instanciateContributions(toolbarActionsExtensionPoint,
           new ToolBarActionsExtensionPointPolicy());
}

private class ToolBarActionsExtensionPointPolicy
                       implements ExtensionPointPolicy {
      boolean isCompatibleContribution(ContributionDefinition) {
           Class 
contributionalType=contributionDefinition.getContributionType();
           return contributionalType.isCompatible(ToolBarAction.class);
           //no additional checking in this example
      }

      injectAdditionalDependencies(Object contributionInstance) {
          ((ToolBarAction)contributionInstance).setEnabled(true); //just to 
be scenceless
      }
}

Thats all. I guess this can be added quite cleanly. And I would enjoy doing
it myself :-).

It would provide great help I guess. The Spring RPC currently suffering
of the lack of defining contributions and using an extension point 
mechanism.

All is described in more detail within the forum article.


Cheers,

Martin (Kersten)

----- Original Message ----- 
From: "Jean-Philippe Gariepy" <ga...@ya...>
To: <spr...@li...>
Sent: Monday, February 21, 2005 4:47 PM
Subject: RE: [Springframework-developer] Custom bean instantiation language?


>
> I choose the { and } characters for the lists and [ ] for the maps.
>
> So instead of...
>
> <bean id="myBean" class="example.MyClass">
>  <property name="someList">
>    <list>
>      <value>item value</value>
>      <ref bean="beanReference"/>
>    </list>
>  </property>
>
>  <property name="someMap">
>    <map>
>      <entry key="key1">
>        <value>value1</value>
>      </entry>
>      <entry key="key2">
>        <value>value2</value>
>      </entry>
>    </map>
>  </property>
> </bean>
>
> ...I have...
>
> <myBean class="example.MyClass">
>  <someList>{item value, @beanReference}</someList>
>  <someMap>[key1=value1, key2=value2]</someMap>
> </myBean>
>
> Note that I've allowed bean references to be keys.  Hence, the following 
> is
> legal:
>
> <myBean class="example.MyClass">
>  <someList>{item value, @beanReference}</someList>
>  <someMap>[@beanReference=value1, key2=value2]</someMap>
> </myBean>
>
> Of course, when a meta-character (@ , [ ] { } =) is part of the key or 
> value,
> an escape character is required:
>
> <myBean class="example.MyClass">
>  <emailAddresses>{user1\@domain1.com, user2\@domain2.com}</emailAddresses>
> </myBean>
>
> Jean-Philippe
>
> --- Cameron Braid <ca...@br...> wrote:
>
>> > -----Original Message-----
>> > From: spr...@li...
>> > [mailto:spr...@li...] On 
>> > Behalf
>> > Of Jean-Philippe Gariepy
>> > Sent: Monday, 21 February 2005 12:29 PM
>> > To: spr...@li...
>> > Subject: Re: [Springframework-developer] Custom bean instantiation
>> > language?
>> >
>> > (This is an opportunity for me to share my thoughts about the bean
>> > factory.)
>>
>> --SNIP--
>>
>> > I've added other lightweight syntaxes for lists and maps.
>> >
>>
>> Can you please share them too. I like the look of this :)
>>
>>
>> Thanks,
>>
>> Cameron
>>
>
>
> =====
> ---------------------------------------
> Jean-Philippe Gariépy (ga...@ya...)
>
> "Quand l'appétit va, tout va."
>                       -Obélix
>
>
>
> __________________________________
> Do you Yahoo!?
> Read only the mail you want - Yahoo! Mail SpamGuard.
> http://promotions.yahoo.com/new_mail
>
>
> -------------------------------------------------------
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> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
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> _______________________________________________
> Springframework-developer mailing list
> Spr...@li...
> https://lists.sourceforge.net/lists/listinfo/springframework-developer