Re: [Xforge-users] Re: Monitoring/Cacheing

[Ulrich M. <ul...@de...>]

> Ulrich Mayring wrote:
> 
> 1) Make a TransformerComponent. It will always know, when it has changed 
> via a simple FileMonitor.
> 
> 2) Invent a way to pass objects instead of Strings with the 
> <xf:parameter> element.
> 
> 3) Now the XSLComponent can implement Unchangeable, because changes only 
> occur, when the transformer component changes.

Suppose we implement this and have the following code:

<xsl:apply>

<xf:parameter name="xml"><foo>bar</foo></xf:parameter>
<xf:parameter name="xsl" type="object">
     <transformer:get>
         <xf:parameter>test1.xsl</xf:parameter>
     </transformer:get>
</xf:parameter>

</xsl:apply>

...

<xsl:apply>

<xf:parameter name="xml"><foo>bar</foo></xf:parameter>
<xf:parameter name="xsl" type="object">
     <transformer:get>
         <xf:parameter>test2.xsl</xf:parameter>
     </transformer:get>
</xf:parameter>

</xsl:apply>

The Transformer component is first called with test1.xsl, then with 
test2.xsl. It needs to keep an internal Hashtable of all transformers it 
creates and when it receives a request for a specific transformer it 
either already has it and returns it or it creates it and saves it 
internally.

However, we have no way of knowing which Transformer component is 
returned by the component manager, so *all* Transformer components have 
to have the same internal Hashtable of transformers. This has two 
disadvantages:

1) Potential for a lot of duplication (every Transformer components 
needs to save every transformer internally).

2) Unnecessary creation of a new transformer (several Transformer 
components may already have it, but the one that is returned to us 
doesn't have it).

Any ideas?

Ulrich

-- 
Ulrich Mayring
DENIC eG, Systementwicklung