Question

I try to bind a bean to a form snippet from the form:

[#ftl/]
[#import "spring.ftl" as spring /]
[#import "panda.ftl" as panda /]

[#import "discoveryProject.ftl" as discoveryProject/]
[#macro defineProjectForm newProject]
[@spring.bind "discoveryProjectDetailsBean"/]

[#if newProject?has_content && newProject =="true"]
<table class="transparentTable">
    <tr>
        <!--Left Part-->
        <td>
            <table>
                <tr>
                    <td>
                        [@spring.showErrors " " "errors"/]
                        <span>Data Source<sup><span style="color: red; ">*</span></sup></span>
                    </td>
                    <td>
                        <select id="dataSourceSelect" onchange="checkSelectChanges()">
                            [#if discoveryProjectLookupBean.dataSources?has_content]
                                [#list discoveryProjectLookupBean.dataSources as dataSource]
                                    <option id="${dataSource.id}" value="${dataSource.name}">${dataSource.name}</option>
                                [/#list]
                            [/#if]
                        </select>
                    [@spring.bind path="discoveryProjectDetailsBean.discoveryProjectBean.dataSource"/]
                    </td>
                </tr>
            </table>

this is submitted to a controller, snippet to this controller:

@RequestMapping("/navigateDiscoveryProject")
ModelAndView navigateDiscoveryProject(@RequestParam("index")String i,@RequestParam("direction")String direction,
        @ModelAttribute("discoveryProjectDetailsBean")DiscoveryProjectDetailsBean discoveryProjectDetailsBean,BindingResult result,HttpSession session)throws Exception{
    logger.info("method invoked");
    int index=Integer.parseInt(i);
    //another code
}

the bean discoveryProjectDetailsBean contains property which is actually another bean discoveryProjectBean this bean’s properties are always null however I bind them myself in the ftl like in the dataSource property example above, all the values of properties to the discoveryProjectBean are always null.

Answer 1

I have found two answers for my problem.
the first way is to bind each property alone, see I was only binding the command object while I should’ve binded each property to its specific controller.
like this

[#ftl/]
[#import "spring.ftl" as spring /]
[#import "panda.ftl" as panda /]

[#import "discoveryProject.ftl" as discoveryProject/]
[#macro defineProjectForm newProject]
// this is useless [@spring.bind "discoveryProjectDetailsBean"/]

[#if newProject?has_content && newProject =="true"]
<table class="transparentTable">
    <tr>
        <!--Left Part-->
        <td>
            <table>
                <tr>
                    <td>
                        [@spring.showErrors " " "errors"/]
                        <span>Data Source<sup><span style="color: red; ">*</span></sup></span>
                    </td>
                    <td>
                        <select id="discoveryProjectBean.dataSource" name="discoveryProjectBean.dataSource" onchange="checkSelectChanges()">
                            [#if discoveryProjectLookupBean.dataSources?has_content]
                                [#list discoveryProjectLookupBean.dataSources as dataSource]
                                    <option id="${dataSource.id}" value="${dataSource.name}">${dataSource.name}</option>
                                [/#list]
                            [/#if]
                        </select>
//the following binding work just fine
                        [@spring.bind path="discoveryProjectDetailsBean.discoveryProjectBean.dataSource"/]
                    </td>
                </tr>
            </table>

what I did above is that I get the property I need from the command object set it as the name and ID of the select tag and binded the tag to the property using @spring.bind.

this is the best solution

an alternative is to do it like this:

[#ftl/]
[#import "spring.ftl" as spring /]
[#import "panda.ftl" as panda /]

[#import "discoveryProject.ftl" as discoveryProject/]
[#macro defineProjectForm newProject]
[@spring.bind "discoveryProjectDetailsBean"/]

[#if newProject?has_content && newProject =="true"]
<table class="transparentTable">
    <tr>
        <!--Left Part-->
        <td>
            <table>
                <tr>
                    <td>
                        [@spring.showErrors " " "errors"/]
                        <span>Data Source<sup><span style="color: red; ">*</span></sup></span>
                    </td>
                    <td>
                        [@spring.bind "dataSources"/]
                [@spring.formSingleSelect "discoveryProjectDetailsBean.discoveryProjectBean.dataSource" dataSources "disabled='disabled' multiple='multiple' class='singleList' onchange='checkValidations()'" /]

                    </td>
                </tr>
            </table>

no this provide less coding but gives limitations with the list of options in your select tag, see you get a list of string to bind it to the @spring.formSingleSelect this is the dataSources in the code above if this list is anything but list of string it will generate a freemarker exception of freemarker.template.TemplateException:.
I hope this would help somebody