Glad to help!
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Allan Casabar
Sent: Thursday, April 01, 2004 5:06 AM
To: [EMAIL PROTECTED]
Subject: Re: [CFCDev] Recursion in CFC
my bad. sorry did not not notice that...
Roland Collins wrote:
>You put the recursive call to "traverse" in the wrong place - it should be
>within the traverse function itself instead of in init. Traverse should
>read like this:
>
><cffunction name="traverse" access="public" output="true" returntype="any">
> <cfargument name="nodeid" type="numeric" required="yes" />
> <cfset var _recordset = "" />
> <cfset var _collectiondao =
>createobject('component','messagegateway') />
> <cfset var i = 0 />
> <cfset var _child = createobject('component', 'nodebean') />
>
> <cfset _recordset = _collectiondao.selectmessagebyparent(
>arguments.nodeid ) />
>
> <cfif _recordset.recordcount>
> <cfscript>
> for(i = 1; i lte _recordset.recordcount; i = i+1){
> writeoutput(_recordset.messageid[i] & '<br />');
> _child = createobject('component', 'nodebean').init(
>_recordset.messageid[i], arguments.nodeid );
> addchild( _child );
>TRAVERSE(_CHILD.NODEID);
> }
> </cfscript>
> <cfelse>
> <cfreturn />
> </cfif>
> </cffunction>
>
>The problem with your current method is that you keep creating new
>instances, which means you never have the shared array "instance.children".
>Some other minor modifications may also need to be done.
>
>Hope this points you in the right direction,
>Roland
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
>Of Allan Casabar
>Sent: Thursday, April 01, 2004 3:59 AM
>To: [EMAIL PROTECTED]
>Subject: [CFCDev] Recursion in CFC
>
>Hello,
>
>I am trying to make a threaded discussion board using CFC. However
>something about recursion in CF / CFC stumped me. It seems that i can't
>make a function return to it's calling function. The result of this
>behaviour is that i will only be able to add the first child of the node
>unless in cases where that current node don't have any children. Sorry
>if i don't make sense. However i copy pasted the source codes and the
>content of the database, expected output, and actual output involved in
>this problem. Any help regarding this problem is greately appreciated.
>
>This is the current contents of the DB / message table
>messageid parentid
>1 0
>2 1
>3 1
>4 2
>5 4
>6 4
>
>
>My output if I invoke generatetree method on treefactory.cfc is
>1
> 2
> 4
> 5
> 6
>
>My expected output is
>1
> 2
> 4
> 5
> 6
> 3
>
>As you can see it only traverse the tree in one direction since it fails
>to return to the calling function and output 3.
>
>Also please bear with my codes since this is just for rapid prototyping
>of the application..
>
><!--- nodebean.cfc --->
><!--- kind of an abstract product for messages --->
><!--- nodeid is the same as messageid for message object --->
><cfcomponent displayname="nodebean">
> <cfscript>
> variables.instance.nodeid = 0;
> variables.instance.parentid = 0;
> variables.instance.children = arraynew( 1 );
> </cfscript>
>
> <cffunction name="init" access="public" output="false"
>returntype="struct">
> <cfargument name="nodeid" type="numeric" required="yes" />
> <cfargument name="parentid" type="numeric" required="yes" />
>
> <cfset setnodeid( arguments.nodeid ) />
> <cfset setparentid( arguments.parentid ) />
> <cfset traverse( arguments.nodeid ) />
>
> <cfreturn this />
> </cffunction>
>
> <!--- getters and setters --->
> <cffunction name="setnodeid" access="public" output="false"
>returntype="void">
> <cfargument name="nodeid" type="numeric" required="true">
> <cfset variables.instance.nodeid= arguments.nodeid/>
> </cffunction>
> <cffunction name="getnodeid" access="public" output="false"
>returntype="numeric">
> <cfreturn variables.instance.nodeid/>
> </cffunction>
> <cffunction name="setparentid" access="public" output="false"
>returntype="void">
> <cfargument name="parentid" type="numeric" required="true">
> <cfset variables.instance.parentid= arguments.parentid/>
> </cffunction>
> <cffunction name="getparentid" access="public" output="false"
>returntype="numeric">
> <cfreturn variables.instance.parentid/>
> </cffunction>
> <cffunction name="addchild" access="public" output="false"
>returntype="void">
> <cfargument name="node" type="struct" required="yes" />
> <cfset arrayappend(variables.instance.children, node) />
> </cffunction>
> <cffunction name="getchildren" access="public" output="false"
>returntype="array">
> <cfreturn variables.instance.children />
> </cffunction>
> <cffunction name="traverse" access="public" output="true"
>returntype="any">
> <cfargument name="nodeid" type="numeric" required="yes" />
>
> <cfset var _recordset = "" />
> <cfset var _collectiondao = createobject('component',
>'messagegateway') />
> <cfset var i = 0 />
> <cfset var _child = createobject('component', 'nodebean') />
>
> <cfset _recordset = _collectiondao.selectmessagebyparent(
>arguments.nodeid ) />
>
> <cfif _recordset.recordcount>
> <cfscript>
> for(i = 1; i lte _recordset.recordcount; i = i+1){
> writeoutput(_recordset.messageid[i] & '<br />');
> _child = createobject('component', 'nodebean').init(
>_recordset.messageid[i], arguments.nodeid );
> addchild( _child );
> }
> </cfscript>
> <cfelse>
> <cfreturn />
> </cfif>
> </cffunction>
></cfcomponent>
>
><!--- tree factory --->
><!-- will take a nodeid as an argument and generate the tree / subtree
>for that node --->
><cfcomponent displayname="treefactory">
> <cffunction name="generatetree" access="public" output="true"
>returntype="any">
> <cfargument name="nodeid" type="numeric" required="yes" />
>
> <cfset var _cruddao = createobject('component', 'messagedao') />
> <cfset var _collectiondao = createobject('component',
>'messagegateway') />
> <cfset var _recordset = "" />
> <cfset var _node = createobject('component', 'nodebean') />
> <cfset var _child = createobject('component', 'nodebean') />
> <cfset var i = 0 />
>
> <cfset _recordset = _cruddao.selectmessage( arguments.nodeid ) />
>
> <cfif _recordset.recordcount>
> <cfscript>
> _node = createobject('component', 'nodebean').init(
>_recordset.messageid, _recordset.parentid );
> </cfscript>
> </cfif>
>
> <cfreturn _node />
> </cffunction>
></cfcomponent>
>
><!--- message gateway--->
><!--- data abstraction layer for queries that will return a collection
>(multiple records) --->
><cfcomponent displayname="messagegateway">
> <cffunction name="selectforumthreads" access="public" output="false"
>returntype="query">
> <cfargument name="forumid" type="numeric" required="no"
>default="0" />
>
> <cfset var qryselectforumthreads = "" />
>
> <cfquery name="qryselectforumthreads" datasource="#request.dsn#"
>username="#request.username#" password="#request.password#">
> SELECT
> *
> FROM
> message
> WHERE
> forumid = <cfqueryparam value="#arguments.forumid#"
>cfsqltype="cf_sql_integer" />
> AND threadid = <cfqueryparam value="0"
>cfsqltype="cf_sql_integer" />
> </cfquery>
>
> <cfreturn qryselectforumthreads />
> </cffunction>
>
> <cffunction name="selectmessagebyparent" access="public"
>output="false" returntype="query">
> <cfargument name="parentid" type="numeric" required="yes" />
>
> <cfset var qryselectmessagebyparent = "" />
>
> <cfquery name="qryselectmessagebyparent"
>datasource="#request.dsn#" username="#request.username#"
>password="#request.password#">
> SELECT
> messageid
> FROM
> message
> WHERE
> parentid = <cfqueryparam value="#arguments.parentid#"
>cfsqltype="cf_sql_integer" />
> </cfquery>
>
> <cfreturn qryselectmessagebyparent />
> </cffunction>
></cfcomponent>
>
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