java - Freemarker and Struts 2, sometimes it evaluates as a sequence+extended_hash -

first let me using struts2 + freemarker real blast. yet there's driving me crazy, because cannot understand why happens. ask here maybe else has idea share it.

i've got action, property. say

private string mytext; 

then i've got setter , getter:

public void setmytext(string mytext) {   this.mytext = mytext; }  public string getmytext() {   if (mytext == null)     mytext = "(empty)";    return this.mytext; } 

the result (in struts.xml) freemarker result. in freemarker template there's line following:

<p>the text is: ${mytext}</p> 

now consider i'm calling action without text parameter: url

http:localhost:8080/myapp/myaction 

as getter provides default value, when action processed , result passed template, property set default; (html on browser side)

<p>the text is: (empty)</p> 

if call action parameter set, instead (i mean like:

http:localhost:8080/myapp/myaction?mytext=hallo 

) things go wrong. freemarker fires following exception:

exception occurred during processing request: "${...}" content: expected string or automatically convertible string (number, date or boolean), has evaluated sequence+extended_hash (string[] wrapped f.e.b.arraymodel) 

it seems "mytext" found twice... doing wrong? or, @ least, there can explain me why happens?

p.s.: it's found twice; following way workaround problem:

<#if mytext?is_sequence>${mytext[0]}<#else>${mytext}</#if> 

yet seems me not viable wrap every variable in way.

p.p.s.: further hint: in freemarker template there's call action lines before. like:

<@s.action var="inneraction" name="gettable" namespace="/foo" /> 

if comment line above, works fine.

the mytext variable freemarker context, if want use action property

<p>the text is: ${action.mytext}</p> 

note action prefix not required access action properties. property resolution method applied when resolving freemarker variables:

property resoloution

your action properties automatically resolved - in velocity view.

for example ${name} result in stack.findvalue("name"), results in action.getname() being executed.

a search process used resolve variable, searching following scopes in order, until value found :

• freemarker variables
• value stack
• request attributes
• session attributes
• servlet context attributes

and later can read objects accessible context.

objects in context

the following variables exist in freemarker views

• req - current httpservletrequest
• res - current httpservletresponse
• stack - current ognlvaluestack
• ognl - ognltool instance class contains useful methods execute ognl expressions against arbitary objects, , method generate select list using pattern. (i.e. taking name of list property, listkey , listvalue)
• struts - instance of strutsbeanwrapper

• action - current struts action

• exception - optional exception instance, if view jsp exception or servlet exception view

the error might caused searches value stack , returning didn't expect depending on structure of stack @ moment of execution. adding prefix variable point out exact location of property should fix redundancy in code when searching in value stack.