Using coldfusion.sql.QueryTable.next() in Coldfusion 9

I am trying to write a custom tag that will iterate over a cfquery object in a special way. I found this page: http://www.zrinity.com/developers/mx/undocumentation/query.cfm outlining how to use the underlying java methods to navigate the result set, but it doesn't seem to be working in CF9.

I can call .next(), .previous(), .first(), and .last() just fine, and each method updates query.currentRow, but referencing query.columnName always returns the value from the first row, not currentRow.

Example:

<cfquery name="testQuery" datasource="source">
  SELECT FooName FROM NumberedFoos
</cfquery>

<cfloop from="1" to="3" index="i">
  <cfoutput>#testQuery.currentRow# =&gt; #testQuery.fooName#</cfoutput><br />
  <cfset testQuery.next()>
</cfloop>

Produces:

1 => Foo 1
2 => Foo 1
3 => Foo 1

I know i could use something like testQuery.fooName[testQuery.currentRow], but that is pretty undesirable for the people I am making the custom tag for. Was the functionality described in the above link removed from CF9? If so is there an alternative?

EDIT

To expand on the why, the开发者_StackOverflow client wants a custom tag that allows them to "assert" certain things about a query. The client has a pretty low level understanding of CF, but are pretty solid writing SQL. Their desired end result is something akin to:

<cfquery name="purchaseTotals">
  SELECT PurchaseId, Total FROM Purchases
</cfquery>

<CF_ASSERT query="purchaseTotals">
  purchaseTotals.Total gte 0
</CF_ASSERT>

The desired output would be a html table with each row being the row from the query that fails the assertion. So to me, the CF_ASSERT tag need to be able to update the current row.

Edit 2:

The main challenge is to allow html in the body of the tag, while still having query values substituted from the appropriate row:

<CF_ASSERT query="purchaseTotals">
  <CF_CONDITION expression="purchaseTotals.Total gte 0">
    <!---error message when expression is false--->
    <cfoutput>
      Purchase #purchaseTotals.purchaseId# has a negative total!
    </cfoutput>
  </CF_CONDITION>
  <CF_CONDITION expression="purchaseTotals.Total eq ''">
    #PurchaseTotals.purchaseId# has a null total, this may be caused by:
    <ul>
      <li>Edge Case 1</li>
      <li>Edge Case 2</li>
    </ul>
  </CF_CONDITION>
<CF_ASSERT>

The output here would be something like:

  Purchase 120 has a negative total!
  Purchase 157 has a negative total!
  Purchase 157 has a null total, this may be caused by:
Edge Case 1
Edge Case 2

Was the functionality described in the above link removed from CF9?

The internal stuff has definitely changed since the article was written in 2006. But I suspect the exact functionality you are describing may not have existed in any mx version. A key difference between your code and the linked examples is the usage of <cfoutput query=".."> (not just a plain <cfoutput>). The query attribute obviously provides some extra context when evaluating the variables. Remove it (like in your example) and the results are "the value from the first row, not currentRow.". Even under MX6, which does not bode well for subsequent versions. That exact functionality probably was not removed. It just never worked to begin with.

If so is there an alternative?

Like I said earlier, the cleanest approach would be to use array notion ie #query.column[row]#. Given that you seem to have rejected that option, you are basically left with evaluate(). You would need to loop through the query within the parent tag. Then use evaluate to process the subtag expression and content. It is not particularly elegant or simple IMO. But I think that may be good as it gets without array notation, or a ritual sacrifice of some kind.

ASSERT.cfm

<cfparam name="attributes.query" type="string">

<cfif thisTag.ExecutionMode is 'start'> 
    <!--- validate attributes.query is a query object --->
    <cfif not ( structKeyExists(caller, attributes.query) AND IsQuery(caller[attributes.query]) )>
        <cfthrow message="Attributes.query [#attributes.query#] is undefined or not a query object">
    </cfif>
</cfif>
<cfif thisTag.ExecutionMode is 'end'> 
    <cfset variables[attributes.query] = caller[attributes.query]> 
    <cfloop query="variables.#attributes.query#">
        <cfloop array="#thisTag.assocAttribs#" index="subTag">
            <cfset variables.matchFound = evaluate(subTag.expression)>
            <cfif variables.matchFound>
                <cfoutput>[#currentRow#] #evaluate(DE(subTag.Content))#</cfoutput><hr>
            </cfif>
        </cfloop>
    </cfloop>
</cfif>

CONDITION.cfm
Note: Do NOT use <cfoutput> tags within the tag content.

<cfparam name="attributes.expression" type="string">
<cfif thisTag.ExecutionMode is "start"> 
    <cfassociate baseTag="CF_ASSERT">
</cfif>
<cfif thisTag.ExecutionMode is "end"> 
    <cfset attributes.content = thisTag.GeneratedContent>
    <cfset thisTag.GeneratedContent = "">
</cfif>

client has a pretty low level understanding of CF, but are pretty solid writing SQL

Having said all that, are things being implemented this way because it is the best approach or because it is most similar to writing SQL ie comfortable ?

Classic example of the inner platform effect.

I would advise you not to do this as you are trying to create a system which mimics built in functionality of the base or running system which ultimately becomes a poorly implemented version of the system in which it is running on / implemented in.

Sounds confusing, I know - but this is a well known anti-pattern to avoid.

See here for more information : http://en.wikipedia.org/wiki/Inner-platform_effect

P.s. what you are looking for (although I disagree with the implementation) is itteration of a query outside of a cfloop, simply use array syntax :

#queryName.fieldName[rowNumber]#

Using this you can itterate the query however you wish, certainly no need for underlying java. Notice we aren't using queryName.currentRow. For previous() next() functionality, you just change the rowNumber up or down.