GitHub user brettryan opened a pull request:
https://github.com/apache/tiles/pull/5
Add support for add-list-attribute to render expressions
When using expressions using the following example:
<put-list-attribute name="breadcrumbs" cascade="true" inherit="true">
<add-list-attribute>
<add-attribute expression="${customer.id}"/>
<add-attribute expression="/customers/${customer.id}/info"/>
</add-list-attribute>
<add-list-attribute>
<add-attribute value="Orders"/>
<add-attribute expression="/customers/${customer.id}/orders"/>
</add-list-attribute>
</put-list-attribute>
We first encounter an NPE when attempting to access this object. This is
due to
[Attribute#toString](https://tiles.apache.org/framework/apidocs/org/apache/tiles/Attribute.html#toString())
returning the value `null` which with the container attempting to turn this
into a binary array cases an NPE. This has been resolved by returning the
string `"null"`.
For the list attributes I have chosen to recursively process any lists
encountered within
[AbstractAttributeEvaluator#evaluate](https://tiles.apache.org/framework/apidocs/org/apache/tiles/evaluator/AbstractAttributeEvaluator.html#evaluate(org.apache.tiles.Attribute,%20org.apache.tiles.request.Request)
to clone each attribute to a new instance with the value set to the evaluated
expression.
**NOTE**: This solution comes with one caveat that is semi-intentional and
you may choose to reject the pull request on this point. Previously a
[ListAttribute](https://tiles.apache.org/framework/apidocs/org/apache/tiles/ListAttribute.html)
would be exposed to the view requiring consumers to make references to the
attributes `value` property before accessing the index to the list.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/brettryan/tiles feature_list_att_exp_support
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/tiles/pull/5.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #5
----
commit 515dc95746aa33bf1472b917d924af3c0bc2dae1
Author: Brett Ryan <[email protected]>
Date: 2015-07-08T15:19:47Z
Correct NPE with Attribute#toString.
commit 41759e82bbc1b4ec15878caba6bf6b659d256886
Author: Brett Ryan <[email protected]>
Date: 2015-07-08T15:26:21Z
Added support for list attributes to have expressions.
- This will certainly need review as the current implementation breaks
current behavior with relation to attributes from list attributes being exposed
to the view, while simple attributes are not.
- This implementation maps everything to the objects represented type where
possible, though due to current requirements elements must remain to be an
attribute wrapping the value.
- Attribute#getExpression is evaluated and set against a cloned version of
Attribute#setValue.
commit be97c75393f9d72cfebe717146db88608427429d
Author: Brett Ryan <[email protected]>
Date: 2015-06-14T23:49:29Z
Added git ignore/attributes.
----
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