Re: Wrapping a grid

[MohammadS <sa...@gmail.com>]

I just needed to do something similar. Basically needed to normalize the
paginated (via database) output of a grid with slightly different queries
going into the db pagination call. 

I know you asked this question a long long long time ago, but thought it'll
be here for the next guys looking for a solution.

The grid component takes an "override" parameter which is supplied via
coercion. The key is to provide a different object that will provide the
grid component with the right set of "paramter" blocks.

There are a few steps. 

1. Create a ContainerPropertyOverrides object that contains both the current
container's "ComponentResources" and the grid component's
"ComponentResources"


Here is a sample of the internals

    private final ComponentResources parent;
    private final ComponentResources self;
    
    private final Messages messages;
    
    public ContainerPropertyOverrides(ComponentResources resources)
    {
        Component container = resources.getContainer();
        if(container != null)
            parent = container.getComponentResources();
        else
            parent = null;
        
        self = resources;
        
        messages = resources.getContainerMessages();
        
    }
    
    @Override
    public Block getOverrideBlock(String name)
    {
        if(parent != null)
        {
            Block b = parent.getBlockParameter(name);
            if(b != null)
                return b;
        }
        
        return self.getBlockParameter(name);
    }

2. contribute a coercion from "ComponentResources" to your newly created
object in step 1

here is what i have

public static void contributeTypeCoercer(Configuration<CoercionTuple>
configuration)
    {
        configuration.add(CoercionTuple.create(ComponentResources.class,
ContainerPropertyOverrides.class,
                new Coercion<ComponentResources,
ContainerPropertyOverrides>()
                {
                    public ContainerPropertyOverrides
coerce(ComponentResources input)
                    {
                        return new ContainerPropertyOverrides(input);
                    }
                }));
    }

3. Setup your component to use all this properly

here is a snippet from my setup

public class MyGridWrapper
{
    //this is just to make sure refactoring efforts in the future don't
break this
    // functionality
    private static final String GRID_ID="myGrid";

    @Parameter(value=GRID_ID, allowNull=false)
    @Property(write = false)
    private ContainerPropertyOverrides overrides;
    
    @Property
    @Component(id=GRID_ID, parameters={"overrides=overrides"})    
    private Grid myGrid;

    //stuff that sets up the source, etc etc
}

Knowing tapestry, there are probably a few other options you have to solving
the problem. 

Last thing i'll mention is that you can do this without contributing a
coercion. Simply supply a default value for overrides and construct the
object yourself. 

You can read about it here:
http://tapestry.apache.org/tapestry5.2-dev/guide/parameters.html

Good luck
-- 
View this message in context: http://tapestry.1045711.n5.nabble.com/Wrapping-a-grid-tp2416039p3214873.html
Sent from the Tapestry - User mailing list archive at Nabble.com.

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org