On 10/19/11 23:38 , Niclas Hedhman wrote:
On Wed, Oct 19, 2011 at 3:17 PM, Rickard Öberg<[email protected]> wrote:
One way to fix it is to allow handlers to make the calls to the REST client,
but don't perform them until the handler method returns, so that the stack
never grows in size.
And one should implement the equivalent of back/forward-button as well?
Not sure how useful that would be for automated REST API clients.
In any case, one of the main issues right now is how to keep the call
stack from growing. It comes for example from this:
} ).onQuery( "commandwithvalue", Links.class, new
ResultHandler<Links>()
{
@Override
public void handleResult( Links result,
ContextResourceClient client )
{
Link link = LinksUtil.withId( "right", result);
client.command( link );
}
} )
---
Here the client.command(link) call will execute the next step, and that
will in turn cause another handler to be called, causing the stack to
constantly grow.
The most obvious way to remove this is to make the handler return the
next step instead, or null if finished.
I.e. something like:
} ).onQuery( "commandwithvalue", Links.class, new
ResultHandler<Links>()
{
@Override
public HandlerCommand handleResult( Links result,
ContextResourceClient client )
{
Link link = LinksUtil.withId( "right", result);
return client.command( link );
}
} )
---
I.e. client.command(link) builds up a command-object of type
HandlerCommand that is returned. This also ensures that a handle-method
only does one thing, and don't try to get imperative by making several
calls to client. The actual work happens after handleResult() has
finished, and the next handler is then invoked. The whole process stops
if either a handler returns null, or there is no handler registered for
the result of a call. That feels like the cleanest way to do this.
With the above there is no reason why a client cannot work indefinitely
against a REST API, doing whatever needs to be done.
/Rickard
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