On Mon, Apr 16, 2012 at 11:26 PM, Vincent Massol <[email protected]> wrote:
>
> On Apr 16, 2012, at 11:11 PM, Vincent Massol wrote:
>
>>
>> On Apr 16, 2012, at 10:23 PM, Jerome Velociter wrote:
>>
>>> On Mon, Apr 16, 2012 at 9:59 PM, Vincent Massol <[email protected]> wrote:
>>>> Hi,
>>>>
>>>> On Apr 16, 2012, at 8:10 PM, Jean-Vincent Drean wrote:
>>>>
>>>>> Hi devs,
>>>>>
>>>>> while replacing calls to xwiki#searchDocuments by calls to the query
>>>>> manager script service I ran into the following query manager issue:
>>>>> http://jira.xwiki.org/browse/XWIKI-7273 (XWQL short form queries
>>>>> should distinct on document fullname.)
>>>>>
>>>>> I think we could use the recent QueryFilter mechanism to handle the
>>>>> addition of the "distinct" in the select statement.
>>>>> https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-query/xwiki-platform-query-manager/src/main/java/org/xwiki/query/QueryFilter.java
>>>>>
>>>>> QueryFilters allow to:
>>>>> - transform queries depending on a dynamic parameter (for example the
>>>>> user preferences in HiddenDocumentFilter)
>>>>> - transform the select part of a short query, without requiring
>>>>> programming rights
>>>>>
>>>>> Here's an example of what it could look like from a velocity script:
>>>>> ----------------------------------------------------8<----------------------------------------------------
>>>>> #set($query =
>>>>> $services.query.xwql("").addFilter("unique").addFilter("hidden"))
>>>>> ----------------------------------------------------8<----------------------------------------------------
>>>>> Note that in the future we could decide that the Query wrapper we use
>>>>> in the QueryManagerScriptService (ScriptQuery) have the "unique"
>>>>> filter by default + a way to remove it from the script.
>>>>>
>>>>> I wasn't expecting us to consider using multiple filters when I added
>>>>> the new APIs in Query (4.0RC1).
>>>>> If we agree that a QueryFilter would be a nice way to handle this, I'd
>>>>> like to break those API before we release 4.0:
>>>>> ----------------------------------------------------8<----------------------------------------------------
>>>>> - Query setFilter(QueryFilter filter);
>>>>> + Query addFilter(QueryFilter filter);
>>>>> - QueryFilter getFilter();
>>>>> + List<QueryFilter> getFilters();
>>>>> ----------------------------------------------------8<----------------------------------------------------
>>>>
>>>> It's a little bit more complex. We did consider several filters when we
>>>> added setFilter()!! :)
>>>>
>>>> We said that if we need more than one filter we could have an AndFilter()
>>>> that takes a list of Filters. And allow more complex filters should we
>>>> need them, like OrFilter, etc.
>>>>
>>>> #set($query = $services.query.xwql("").setFilter(new AndFilter("unique",
>>>> "hidden"))
>>>>
>>>> Written with a fluent API that would give:
>>>>
>>>> #set($query = $services.query.xwql("").setFilter(and("unique", "hidden"))
>>>>
>>>> Or even:
>>>>
>>>> #set($query = $services.query.xwql("").setFilter("unique").and("hidden")
>>>>
>>>> Anyway I'm just mentioning this to explain what we thought about and an
>>>> alternative to addFilter(). The only problem with addFilter() is if you
>>>> need more complex Filters later on. It's not extensible whereas using
>>>> AndFilter() and OrFilter() is more extensible at the expense of a little
>>>> bit more text if not using a fluent api.
>>>
>>> Also you can't expose it that easily in velocity. For example your
>>> fluent APIs examples above won't work in velocity ; you would need a
>>> layer in between to adapt from script service APIs to the Java APIs.
>>
>> You can't do a "new" but the point of the fluent API is to not have to write
>> any "new" (to make it fluent) and thus it's well adapted to Velocity
>> actually :)
>>
>> BTW on http://en.wikipedia.org/wiki/Fluent_interface#Java their examples
>> shows a usage where they call setParameter several times.
>>
>> This is also a possibility. We can call setFilter() several times.
>
> BTW another possibility is:
>
> ...setFilter("unique").and().setFilter("hidden")
To me the "or" filter combination does not make sense in this context
- filters aren't booleans AFAIK ; so I don't think this type of
chaining brings anything compared to
addFilter("unique").addFilter("hidden")
Jerome
>
> I had found a nice blog post on how to implement chaining like this with an
> order but I cannot find it again.
>
> Thanks
> -Vincent
>
>> Thanks
>> -Vincent
>>
>>> Jerome.
>>>
>>>>
>>>> Anyway I'm fine with either addFilter or setFilter.
>>>>
>>>> Also +1 to use a QueryFilter for adding a "distinct" in the query.
>>>>
>>>> Thanks
>>>> -Vincent
>>>>
>>>>> WDYT ?
>>>>> JV.
>
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--
Jérôme Velociter
Winesquare
http://www.winesquare.net/
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