Good day to you, Jiaqi,
Ah..yes. I also don't understand the purpose of that indexOf("/"). The only
use case I can think of for that is that when the "/" is inside the curly
braces....which I don't think is recommendable anyway.
But like what you said, the first argument of ${x.y.z} is irrelevant for the
expression evaluator. Thus, it will still not return null.
Btw, what are you trying to retrieve with ${plugin} -
org.apache.maven.model.Plugin? If so, on top of my head, I suggest getting
all the build plugins and searching for the build plugin which matches
${plugin.groupId} ${plugin.artifactId}, and ${plugin.version}. ...But I am
not sure though why would you want the model of the Plugin.
Btw, for more information about the Maven Properties, kindly check [1].
Cheers,
Franz
[1] http://docs.codehaus.org/display/MAVENUSER/MavenPropertiesGuide
Jiaqi Guo wrote:
>
> Hi Franz,
>
> I tried to get PluginDescriptor within a mojo and got
> PluginParameterException, then I started looking at this code.
>
> Assume expression is string "plugin", pathSeparator is -1, the
> expression.substring(1) becomes "lugin". Did I miss anything here?
>
> And then looking at ReflectionValueExtractor.java today, I just realized
> ReflectionValueExtractor.evaluate("lugin", pluginDescriptor) may work
> since the first argument is irrelevant if string doesn't contain '.'.
> But I'm more confused by the substring part of what .indexOf("/") is for.
>
> And still, in my Mojo, the parameter with expression "${plugin}" is
> causing PluginParameterException which indicates the value of it is null.
>
> Regards
> -Jiaqi
>
> franz see wrote:
>> Good day to you, Jiaqi,
>>
>> Why do you say that it will be evaluted to null?
>>
>> Cheers,
>> Franz
>>
>>
>> Jiaqi Guo wrote:
>>
>>> Hi there,
>>>
>>> I'm trying to find out the build-in variables for a maven2 plugin and
>>> found the following code in
>>> http://svn.apache.org/repos/asf/maven/components/tags/maven-2.0.4/maven-core/src/main/java/org/apache/maven/plugin/PluginParameterExpressionEvaluator.java
>>> line 217:
>>>
>>> ...
>>> else if ( expression.startsWith( "plugin" ) )
>>> {
>>> try
>>> {
>>> int pathSeparator = expression.indexOf( "/" );
>>>
>>> PluginDescriptor pluginDescriptor =
>>> mojoDescriptor.getPluginDescriptor();
>>>
>>> if ( pathSeparator > 0 )
>>> {
>>> String pathExpression = expression.substring( 1,
>>> pathSeparator );
>>> value = ReflectionValueExtractor.evaluate(
>>> pathExpression, pluginDescriptor );
>>> value = value + expression.substring( pathSeparator
>>> );
>>> }
>>> else
>>> {
>>> value = ReflectionValueExtractor.evaluate(
>>> expression.substring( 1 ), pluginDescriptor );
>>> }
>>> }
>>> catch ( Exception e )
>>> {
>>> // TODO: don't catch exception
>>> throw new ExpressionEvaluationException( "Error
>>> evaluating plugin parameter expression: " + expression,
>>> e );
>>> }
>>> }
>>> ...
>>>
>>> If I didn't miss anything this code make the value of any parameter
>>> expression starting with "plugin" to be null for sure, which will cause
>>> PluginParameterException in
>>> org.apache.maven.plugin.DefaultPluginManager.checkRequiredParameters(DefaultPluginManager.java:809).
>>>
>>> Same thing happens to "settings" and "project".
>>>
>>> Is this a bug of maven-2.0.4? Is there any way to get pluginDescriptor
>>> in Mojo?
>>>
>>>
>>>
>>> Regards
>>>
>>> --
>>>
>>>
>>> Jiaqi Guo
>>>
>>> http://www.cyclopsgroup.org
>>> [EMAIL PROTECTED]
>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: [EMAIL PROTECTED]
>>> For additional commands, e-mail: [EMAIL PROTECTED]
>>>
>>>
>>>
>>>
>>
>>
>
>
> --
>
>
> Jiaqi Guo
>
> http://www.cyclopsgroup.org
> [EMAIL PROTECTED]
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
>
--
View this message in context:
http://www.nabble.com/Can-anyone-explain-this-code-tf3218981s177.html#a8962743
Sent from the Maven - Users mailing list archive at Nabble.com.
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
