FreeMarker Templates

iKnowBase supports the use of FreeMarker templates. When using FreeMarker templates, you will combine static markup, standard FreeMarker functionality and iKnowBase model objects to create the desired output:

• Static markup is the static text that you want output from the template. This is typically HTML, but can really be any kind of text that you want, for example to generate XML, RSS or JSON.
• iKnowBase model objects are the data that iKnowBase makes available to you.
• Standard FreeMarker functionality are directives and expressions that allow you to iterate over, print and otherwise manipulate the model objects.

In order to best utilize the FreeMarker technology, you should read the FreeMarker documentation available at http://freemarker.org/docs. Some key features are described below, but this covers only a small subset of the capabilities.

About FreeMarker

With FreeMarker you can create HTML-based templates that can display data from a Java model. The following figure shows how FreeMarker connects with a template (in this instance an HTML template), and data from a Java object model. This connection generates an HTML output that displays the data in the template.

Includes and imports

FreeMarker supports <#include> and <#import> as mechanisms to reuse templates. With iKnowBase, it is possible to use both of these mechanisms to refer to templates stored inside the iKnowBase repository:

• First, create an iKnowBase template in iKnowBase Development Studio. Take note of the GUID of the template, listed at the bottom of the screen.
• Next, refer to this template using the special filename “/urn:iknowbase:template:guid:” + guid, for example <#include "/urn:iknowbase:template:guid:9E23B9E919E73ECCE040000A18006DD1">

FreeMarker Directives

FTL tags are used to call directives. There are two types FTL tags:

• Start-tag: <#directive name parameters>
• End-tag: </#directive name>

These tags are similar to the syntaxes in the HTML code and the XML code except for tags that start with #. There are two types of directives: predefined directives and user-defined directives. User defined directives use @ instead of #. For example, <@mydirective parameter>... </@mydirective>.

The format of the parameters depends on the name of the directive.

    <#if condition>
    ...
    <#elseif condition2>
    ...
    <#elseif condition3>
    ...
    <#else>
    ...
    </#if>

    <#if x == 1>
        x is 1  
    <#elseif x == 2>
        x is 2  
    <#else>
        x is neither 1 nor 2
    </#if>

ikbProperty. switch, case, default, break

Syntax:

    <#switch value>
        <#case refValue1>  
        ...
        <#break>
        <#case refValue2>
        ...
        <#break>
        ...
        <#case refValueN>
        ...
        <#break>
        <#default>
        ...
    </#switch>

    <#switch x>
        <#case x = 1>
        x is 1
        <#case x = 2>
        x is 2
        <#default>
        x is neither 1 nor 2
    </#switch>

ikbProperty. list, break

This directive is used to loop through a list of items:

    <#list sequence as item>
        Item = ${item}
    </#list>

p.For example:

    <#assign seq = ["winter", "spring", "summer", "autumn"]>
    <#list seq as x>
        ${x_index + 1}. ${x}<#if x_has_next>,</#if>  
    </#list>

ikbProperty. Assign

This directive is used to create a variable:

<#assign name=value>

    <#assign name>
    This is the value assigned to name
    </#assign>

<#assign seasons = ["winter", "spring", "summer", "autumn"]>

If you want to write values directly within the insertion brackets ${ and }, there are some characters that need a specific syntax.

Built-in Functions

FreeMarker contains a set of built-in functions that you can use directly with variables.

Built-ins for strings

Built-ins for numbers

Built-ins for dates