Anaxa Gore ha scritto:
> Hi!
>
> I am currently writing a wrapper; to "convert" java beans to features,
> throw the SimpleFeature interface...
> But there are choices to do, and i would be happy to have your suggestions !
Sorry for the late response...
> The idea is this :
>
> In an application, we have a model (MVC pattern for instance), described
> by some classes observing the bean norme.
> We manage this model trow the wrapper, which allow us to consider this
> model as features for the geotools.
>
> The SimpleFeatureWrapper is built like this :
>
> public class SimpleFeatureWrapper implements SimpleFeature{
> /** The bean to wrap. */
> Object bean = null;
> /** The list of bean properties. */
> Map<String,Object> props = null;
>
> public SimpleFeatureWrapper(Object bean) throws
> IllegalAccessException,
> InvocationTargetException,
> NoSuchMethodException{
> this.bean = bean;
> props = PropertyUtils.describe(this.bean);
>
> /* Here, we remove the property "class", given for all
> * beans, describing the class of bean. (not needed as an
> attribute ?)
> */
> for(Iterator<String> it = props.keySet().iterator(); it.hasNext();){
> String key = it.next();
> if(key.compareTo("class") == 0)
> it.remove();
> }
> }
> }
>
> Problems appear when implementing functions of SimpleFeature, and
> especially methods of Property, Attribute, ComplexAttribute and Feature.
>
> My questions are :
>
> * What is exactly the interface Name (getAttribute(Name name),
> setAttribute(Name name)...). Is there an implementation of this ?
> How can i do a link between the "Name", and the String describing
> my property in the Map ?
SimpleFeature is basically a generic Feature plus all the methods the
old gt2 feature provided. You can safely assume nothing in the current
api is using getAttribute(Name). Anyways, Name is a qualified name, that
is, a straight name + namespace, which is used in complex features
because it's unfortunately very possible that a feature has attributes
coming from different namespaces (in fact, even a simple feature has,
there are a few like "name" that should come from the gml namespace).
> * What can I return in the getDefaultGeometry() ? A very simple idea
> is to scan the Map, trying to find an object instance of Geometry,
> and return the first found... any other idea ?
That's what the current simple feature do. Return the first geometry
in the schema.
> * What can I return in the getFeatureType() ? An idea is to create
> dynamically a SimpleFeatureType from the bean, after getting its
> properties. Is it really a good idea ? I am not sure. Another way
> could be forcing the user to create a SimpleFeatureType for its
> bean, and pass it throw the construcor. Any other idea ?
FeatureType is static information, so I'd suggest you create a class
that has the ability to turn a Class into a FeatureType and that caches
the result. And then you can use the feature type to drive your
simple feature implementation as well (since the Class -> featureType
converter will already had to
> * Is there a way to create a BoundingBox ? I could not find any
> information about how to do it ?
The current simple feature implementation scans over the geometry
attributes and grabs their aggregated bbox. It basically uses JTS.
You can then wrap it into a ReferencedEnvelope.
> * setAttributes(List or Object[]). It s too bad this methods can't
> throw any exception... We could test each elements of list or tab,
> compare their type with properties type in the Map and throw an
> exception is the instanceof is false ! Actually, I can't see how
> to do this without exception...
You're free to thorw an unckecked exception like RuntimeException or
InvalidAttributeException or something like that.
Cheers
Andrea
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