Datasqueezers and strategies

[Rob Dennett <ro...@tmit1.org>]

I created a simple component that takes a complex class as a parameter and iterates over it, outputting one of its values.  When I initially tried to run this, I got an exception saying, “Could not find a strategy instance for class Foobar”.

 

I made the class in question implement Serializable (although I didn’t define a serialVersionUID), but now I get a NotSerializableException.  The class in question contains a list of other objects as well.  Do I need to create a datasqueezer adaptor for this?  Why?  What do they do, exactly?

 

Also, if I am dealing with a complex object graph, is it inappropriate to pass it to a component?

 

Thanks for your help,

Rob


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Re: Datasqueezers and strategies

[Kent Tong <ke...@cpttm.org.mo>]

Rob Dennett <rob_dennett <at> tmit1.org> writes:

> I made the class in question implement Serializable (although I didn’t 
> define a serialVersionUID), but now I get a NotSerializableException.  
> The class in question contains a list of other objects as well.  Do I 
> need to create a datasqueezer adaptor for this?  

No. Just make sure the objects in the your object graph are all
Serializable.

> Why?  What do they do, exactly?

So that they can be stored as strings in the HTML page in the browser.
The strings will be turned back into objects on rewind.

> Also, if I am dealing with a complex object graph, is it inappropriate to pass 
> it to a component?

To cut down the network traffic, you may want to just store their keys
in the HTML page. To do that, use the "converter" or "keyExpression"
parameter of the "For" component.

--
Author of a book for learning Tapestry (www.agileskills2.org/EWDT)


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