libreccm-legacy/doc/themes-with-freemarker/themes-with-freemarker.md

Creating themes for LibreCCM with Freemarker

Starting with version 2.5 the LibreCCM platform support Freemarker as an alternative to XSL. Freemarker is a project of the Apache Foundation and a well known and mature template engine for Java. The support for Freemarker in version 2.5 is a backport from the upcoming version 7 of the LibreCCM platform.

Compared to XSL Freemarker is a lot easier to use, especially if you have worked with other template engines like Twig, Velocity etc before. In version 7 of the LibreCCM platform Freemarker will be become the primary template engine. XSL will still be supported, but we recommanded that you port your themes to Freemarker. Why Freemarker and not one of the other template engines? Freemarker is able to process XML in a similar way than XSL.

Freemarker also allows it to define user defined directivies and functions. To make it easier to create impressive themes we provide functions and macros for Freemarker we provide several functions and macros which hide the complexity of the XML data model created by CCM from the template author. It is recommanded not to access the XML data model directly. Instead the provided functions should be used. Otherwise your theme might brake when the XML structure changes.

General structure of a Freemarker theme

Freemarker themes have a different structure than the usual "old style" themes of LibreCCM. Each Freemaker based theme must have a theme manifest file called theme.json on the root of its directory structure. This file provides several informations for processing the theme and serves as a central configuration point. The file must have the following structure:

{
    "name": "an-example-theme",
    "templates": {
        "applications": [
            {
                "application-name": "someApp",
                "application-class": "somePageClass",
                "template": "/templates/someApp.html.ftl"
            },
            ...                
        ],
        "contentitems": [
            {
                "view": "list",
                "contentType": "com.arsdigita.cms.contenttypes.Article",
                "template": "/templates/contentitems/list/article.html.ftl"
            },
            {
                "view": "details",
                "contentType": "com.arsdigita.cms.contenttypes.Article",
                "template": "/templates/contentitems/detail/article.html.ftl"
            },
            {
                "view": "details",                    
                "contentType": "com.arsdigita.cms.contenttypes.Article",
                "style": "fancy",
                "template": "/templates/contentitems/detail/article.html.ftl"
            },
            ...
        ],
        "default-application-template": "/templates/default-layout.html.ftl",
        "default-contentitem-template": "/templates/contentitems/detail/default.html.ftl",
    },
    "data-time-formats": [
        {
            "style": "event",
            "lang": "de",
            "format": "dd. MMM. YYYY"
        },
        {
            "style": "event",
            "lang": "en",
            "format": "MM/dd/YY"
        },
        ...
    ]
}

The name key defines the name of the theme which should be unique per installation. The templates contains several subkeys which define the templates to use.

The objects in the array of the applications key specify which template is used for an application. To determine which template should be used the attributes application and and class of from the root element of the XML data model are used. The value of the application attribute is matched against the value for the application-name field, the value of the class attribute against the value of the application-class field.

CCM will first try to find a a template definition which matches both the class and the application. If none is found a template definition which a matching application-name and an empty application-class will be looked up. If there is no match the template defined as default-application-template is used.

There is one special value value for the template field: XSL_FALLBACK.XSL. If the template field is set to this value CCM will fallback to the old XSL themes.

For content items the procedure is similar, only the names of the fields in the template definition differ. The view field is used internally to select either the detail or the list view. The contentType field is the content types of the content items. The third field style is optional and can be used to select different templates depending on the theme context. For more informations please refer to the documentation of the contentItem macro provided by the ccm-cms module.

The date-time-formats section is used to define date-time formats to use with the formatDateTime function provided by ccm-themedirector.

Predefined variables and functions

Several variables and functions are predefined and available without importing another file.

Variables

contextPath

The context path in which CCM is running.

contextPrefix

The context prefix.

dispatcherPrefix

Prefix for the CCM dispatcher (usually /ccm)

host

The current host.

model

The XML document created by LibreCCM.

negotiatedLanguage

The language negoiated between the user agent and LibreCCM.

requestScheme

The protocol (http or https).

selectedLanguage

The language selected by the user.

themePrefix

The prefix of the theme. Only available if a development theme is viewed.

Functions

getLocalizedText

String getLocalizedText(String key)

Returns the localized text from the resource bundle of the theme.

getContentItemTemplate

String getContentItemTemplate(String objectType, view="DETAIL", style="")

This is an internal function!

Returns the path for the template of a content item of a specific type.

_formatDateTime

An internal functions date time formatting. This functions should not be used directly.

Functions and Macros