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Posted to dev@uima.apache.org by Jörn Kottmann <ko...@gmail.com> on 2009/08/12 18:22:32 UTC

generics: additionalParams

The additionalParams Map has a String key and can contains
all kinds of Objects, so the correct generification would be Map<String, 
Object>.

In the uima code base I found one invocation where a Properties object was
passed as additionalParams. Properties is a Map<Object, Object> which
will cause compile errors in user code when they use a Properties object 
to pass
in the additional params.
I don't think its common practice to use Properties for additional params.

Should we change it anyway and add a known issue to our release notes ?

Jörn

Re: generics: additionalParams

Posted by Jörn Kottmann <ko...@gmail.com>.
Jörn Kottmann wrote:
> The additionalParams Map has a String key and can contains
> all kinds of Objects, so the correct generification would be 
> Map<String, Object>.
>
> In the uima code base I found one invocation where a Properties object 
> was
> passed as additionalParams. Properties is a Map<Object, Object> which
> will cause compile errors in user code when they use a Properties 
> object to pass
> in the additional params.
> I don't think its common practice to use Properties for additional 
> params.
>
Any opinions on this ?

Jörn

Re: generics: additionalParams

Posted by Marshall Schor <ms...@schor.com>.
+1 Marshall

Jörn Kottmann wrote:
> Jörn Kottmann wrote:
>> Marshall Schor wrote:
>>> Jörn Kottmann wrote:
>>>  
>>>> The additionalParams Map has a String key and can contains
>>>> all kinds of Objects, so the correct generification would be
>>>> Map<String, Object>.
>>>>
>>>> In the uima code base I found one invocation where a Properties object
>>>> was
>>>> passed as additionalParams. Properties is a Map<Object, Object> which
>>>> will cause compile errors in user code when they use a Properties
>>>> object to pass
>>>> in the additional params.
>>>> I don't think its common practice to use Properties for additional
>>>> params.
>>>>
>>>>     
>>>
>>> If we fix the one found use cited above, are there any other cases
>>> where
>>> instances of Properties are passed as additionalParams in our own code?
>>> What do we think is the likelyhood that users will use Properties as
>>> instances of additional params?
>>> Our documentation says "See the Javadocs" for info on the additional
>>> parameters.  The Javadocs say this is a Map ... Valid parameter names
>>> are defined as constants on the XYZ Interface ... and in that
>>> interface,
>>> these constants are Strings.
>>>
>>> But users might decide to represent these parameters in a properties
>>> file.
>>>
>>> Here are some considerations (apologies if I get this wrong - please
>>> correct):
>>>  - If we declare as <Object, Object>, then you cannot assign a
>>> Map<String, Object> to the parameter.
>>>  - Having the key of the map be an Object is more general, and would
>>> accommodate Properties.
>>>  - declaring as <String, Object> - cannot assign  "new Properties()" to
>>> it any more, unless you do the double-fisted cast
>>> (Map<String,Object>)(Object)
>>>
>>> If that is the trade off, I think I would rather have it be <String,
>>> Object>.
>>>   
>> +1 from me for Map<String, Object>
> If there are no objections I would like to start with the change
> to get it done before our 28th deadline.
>
> Jörn
>

Re: generics: additionalParams

Posted by Jörn Kottmann <ko...@gmail.com>.
Jörn Kottmann wrote:
> Marshall Schor wrote:
>> Jörn Kottmann wrote:
>>   
>>> The additionalParams Map has a String key and can contains
>>> all kinds of Objects, so the correct generification would be
>>> Map<String, Object>.
>>>
>>> In the uima code base I found one invocation where a Properties object
>>> was
>>> passed as additionalParams. Properties is a Map<Object, Object> which
>>> will cause compile errors in user code when they use a Properties
>>> object to pass
>>> in the additional params.
>>> I don't think its common practice to use Properties for additional
>>> params.
>>>
>>>     
>>
>> If we fix the one found use cited above, are there any other cases where
>> instances of Properties are passed as additionalParams in our own code? 
>>
>> What do we think is the likelyhood that users will use Properties as
>> instances of additional params?
>> Our documentation says "See the Javadocs" for info on the additional
>> parameters.  The Javadocs say this is a Map ... Valid parameter names
>> are defined as constants on the XYZ Interface ... and in that interface,
>> these constants are Strings.
>>
>> But users might decide to represent these parameters in a properties file.
>>
>> Here are some considerations (apologies if I get this wrong - please
>> correct):
>>  - If we declare as <Object, Object>, then you cannot assign a
>> Map<String, Object> to the parameter.
>>  - Having the key of the map be an Object is more general, and would
>> accommodate Properties.
>>  - declaring as <String, Object> - cannot assign  "new Properties()" to
>> it any more, unless you do the double-fisted cast
>> (Map<String,Object>)(Object)
>>
>> If that is the trade off, I think I would rather have it be <String,
>> Object>.
>>   
> +1 from me for Map<String, Object>
If there are no objections I would like to start with the change
to get it done before our 28th deadline.

Jörn

Re: generics: additionalParams

Posted by Jörn Kottmann <ko...@gmail.com>.
Marshall Schor wrote:
> Jörn Kottmann wrote:
>   
>> The additionalParams Map has a String key and can contains
>> all kinds of Objects, so the correct generification would be
>> Map<String, Object>.
>>
>> In the uima code base I found one invocation where a Properties object
>> was
>> passed as additionalParams. Properties is a Map<Object, Object> which
>> will cause compile errors in user code when they use a Properties
>> object to pass
>> in the additional params.
>> I don't think its common practice to use Properties for additional
>> params.
>>
>>     
>
> If we fix the one found use cited above, are there any other cases where
> instances of Properties are passed as additionalParams in our own code? 
>
> What do we think is the likelyhood that users will use Properties as
> instances of additional params?
> Our documentation says "See the Javadocs" for info on the additional
> parameters.  The Javadocs say this is a Map ... Valid parameter names
> are defined as constants on the XYZ Interface ... and in that interface,
> these constants are Strings.
>
> But users might decide to represent these parameters in a properties file.
>
> Here are some considerations (apologies if I get this wrong - please
> correct):
>  - If we declare as <Object, Object>, then you cannot assign a
> Map<String, Object> to the parameter.
>  - Having the key of the map be an Object is more general, and would
> accommodate Properties.
>  - declaring as <String, Object> - cannot assign  "new Properties()" to
> it any more, unless you do the double-fisted cast
> (Map<String,Object>)(Object)
>
> If that is the trade off, I think I would rather have it be <String,
> Object>.
>   
+1 from me for Map<String, Object>

Jörn

Re: generics: additionalParams

Posted by Marshall Schor <ms...@schor.com>.

Jörn Kottmann wrote:
> Marshall Schor wrote:
>> Jörn Kottmann wrote:
>>  
>>> The additionalParams Map has a String key and can contains
>>> all kinds of Objects, so the correct generification would be
>>> Map<String, Object>.
>>>
>>> In the uima code base I found one invocation where a Properties object
>>> was
>>> passed as additionalParams. Properties is a Map<Object, Object> which
>>> will cause compile errors in user code when they use a Properties
>>> object to pass
>>> in the additional params.
>>> I don't think its common practice to use Properties for additional
>>> params.
>>>
>>>     
>>
>> If we fix the one found use cited above, are there any other cases where
>> instances of Properties are passed as additionalParams in our own
>> code?   
> There was only one case in the uimaj code base (I did not check sandbox).
>
>> What do we think is the likelyhood that users will use Properties as
>> instances of additional params?
>> Our documentation says "See the Javadocs" for info on the additional
>> parameters.  The Javadocs say this is a Map ... Valid parameter names
>> are defined as constants on the XYZ Interface ... and in that interface,
>> these constants are Strings.
>>
>> But users might decide to represent these parameters in a properties
>> file.
>>
>> Here are some considerations (apologies if I get this wrong - please
>> correct):
>>  - If we declare as <Object, Object>, then you cannot assign a
>> Map<String, Object> to the parameter.
>>  - Having the key of the map be an Object is more general, and would
>> accommodate Properties.
>>   
> If you prefer the option to have an Object as key the map
> could be declared as Map<?, ?>.
>
> Having a map which contains objects of an unkown type has the
> disadvantage
> that it is not possible to insert new objects, which is something we
> do frequently
> in our implementations.

hmmm, yes, that would seem to be a pretty strong reason not to use that
form ;-)  -Marshall
>
> Jörn
>

Re: generics: additionalParams

Posted by Jörn Kottmann <ko...@gmail.com>.
Marshall Schor wrote:
> Jörn Kottmann wrote:
>   
>> The additionalParams Map has a String key and can contains
>> all kinds of Objects, so the correct generification would be
>> Map<String, Object>.
>>
>> In the uima code base I found one invocation where a Properties object
>> was
>> passed as additionalParams. Properties is a Map<Object, Object> which
>> will cause compile errors in user code when they use a Properties
>> object to pass
>> in the additional params.
>> I don't think its common practice to use Properties for additional
>> params.
>>
>>     
>
> If we fix the one found use cited above, are there any other cases where
> instances of Properties are passed as additionalParams in our own code? 
>   
There was only one case in the uimaj code base (I did not check sandbox).

> What do we think is the likelyhood that users will use Properties as
> instances of additional params?
> Our documentation says "See the Javadocs" for info on the additional
> parameters.  The Javadocs say this is a Map ... Valid parameter names
> are defined as constants on the XYZ Interface ... and in that interface,
> these constants are Strings.
>
> But users might decide to represent these parameters in a properties file.
>
> Here are some considerations (apologies if I get this wrong - please
> correct):
>  - If we declare as <Object, Object>, then you cannot assign a
> Map<String, Object> to the parameter.
>  - Having the key of the map be an Object is more general, and would
> accommodate Properties.
>   
If you prefer the option to have an Object as key the map
could be declared as Map<?, ?>.

Having a map which contains objects of an unkown type has the disadvantage
that it is not possible to insert new objects, which is something we do 
frequently
in our implementations.

Jörn

Re: generics: additionalParams

Posted by Marshall Schor <ms...@schor.com>.
Jörn Kottmann wrote:
> The additionalParams Map has a String key and can contains
> all kinds of Objects, so the correct generification would be
> Map<String, Object>.
>
> In the uima code base I found one invocation where a Properties object
> was
> passed as additionalParams. Properties is a Map<Object, Object> which
> will cause compile errors in user code when they use a Properties
> object to pass
> in the additional params.
> I don't think its common practice to use Properties for additional
> params.
>

If we fix the one found use cited above, are there any other cases where
instances of Properties are passed as additionalParams in our own code? 

What do we think is the likelyhood that users will use Properties as
instances of additional params?
Our documentation says "See the Javadocs" for info on the additional
parameters.  The Javadocs say this is a Map ... Valid parameter names
are defined as constants on the XYZ Interface ... and in that interface,
these constants are Strings.

But users might decide to represent these parameters in a properties file.

Here are some considerations (apologies if I get this wrong - please
correct):
 - If we declare as <Object, Object>, then you cannot assign a
Map<String, Object> to the parameter.
 - Having the key of the map be an Object is more general, and would
accommodate Properties.
 - declaring as <String, Object> - cannot assign  "new Properties()" to
it any more, unless you do the double-fisted cast
(Map<String,Object>)(Object)

If that is the trade off, I think I would rather have it be <String,
Object>.

-Marshall


> Should we change it anyway and add a known issue to our release notes ?
>
> Jörn
>
>