How to use the forrest:view config-DSL

This part of the views is dedicated to webdesigner and user with some knowlegde of css.

This how-to will show you how to write a forrest:view from ground on. We will focus on html as output format. As well it will show how to add your own css implementation to the view.

• You have a ready-to-go new seed (newSeed) based on views like described in Install views.
• This includes as well all additional plugins that are mentioned in Install views.
• Reading that how-to is as well a good idea to understand the used dir-structure in this how-to.

We developed forrest:view to let the user decide where to place elements in e.g. html-pages. We started this work with the skinconf.xml where you could configure certain elements and their positions. This elements was known under certain names. It was up to the skin-designer to support this configuration and the elements.

The work started with grouping elements (the ones from skinconf). We used css-contracts that we added as @attributes e.g. <div id="content-main"/> . That made it possible to use the same elements in different skins. For the full list refer to the inicial contract list

Around this contracts we developed a configuration Domain Specific Language and called it forrest:view . forrest:view 's allows us to define the order in which forrest:contract's appear, and also to group them using forrest:hook's.

forrest:hook's are container that are only used for layout reasons. They do not add any content nor functionality to the output. They add only layout information to the output. Actually a <forrest:hook name="layoutId"/> will be transformed to <div id="layoutId"/>

forrest:contract's are functionality or extra content that a skin can use to display the requested document (content-main). Sometimes a contract delivers format-specific markup, other times it delivers a format-independent string.

Empty view file

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">    
  </forrest:view>  
</forrest:views>
      

forrest:view is designed to be open for any format that can use forrest:view as configuration file. The only format we implemented is xhtml for now. This is as well true for the delivered contracts.

Now lets start to skin our site. :)

Creating your first view

In this section we will create a new view. We will override the default view of the view-plugin for the index page of the newSeed. For that we will create a file called index.ft and save it in our xdocs directory. This will make only the index.html page look different from the rest of the project.

Remember: pointing your browser to http://localhost:8888/ls.contracts.html will show a page with all contracts that you can use in your project.

Let use the blank view from the earlier step and add the content-main contract. In ls.contracts.html we find the information how to use the contract in our view. Our index.fv should look like:

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">    
    <forrest:contract name="content-main"/>
  </forrest:view>  
</forrest:views>
      

Let's try our new view by pointing to http://localhost:8888/index.html. We will see only the main content. :) Now let's add the section navigation to our view. The contract usage in the view can be looked up in ls.contracts.html. Our view now looks like:

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">    
    <forrest:contract name="content-main"/>
    <forrest:contract name="nav-section"/>
  </forrest:view>  
</forrest:views>
      

We find now the main content and the section navigation after each other and in the order we placed them in the view, but we want it next to each other (left: nav-section; right: content-main).

Hooks in views

We will use now the first time a <forrest:hook name="layoutId"/>. Hooks are the styling side of views. We can imitate arbitrary html skeleton with their help. Before we explain how to use your own css in views we will use the default css. In the default.css we can find

/* menu */
#leftbar {
    width: 25%;
    float: left;
    background: #eae8e3;
    border: thin dashed #565248;
}
      

With this information we know to use <forrest:hook name="leftbar"/> and add contracts into that container.

If we want to put the nav-section contract into the left side position of the site we need to place the contract into that hook. Like:

<forrest:hook name="leftbar">
  <forrest:contract name="nav-section"/>
</forrest:hook>
			

Our view will then look like:

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">
    <forrest:hook name="leftbar">
      <forrest:contract name="nav-section"/>
    </forrest:hook>
    <forrest:contract name="content-main"/>   
  </forrest:view>  
</forrest:views>
      

CSS in views

We know now how to place contracts and hooks in our view, till this stage we only used the default.css. CSS-support of views is as easy as placing contracts/hooks. To override the default.css stylesheet we use another tag within our view <forrest:css url="default.css"/>.

We will now create a file in {project:skins-dir}{path}/{name}.css. In our case we will save a file called howTo.css in newSeed/src/documentation/skins/css/howTo.css containing only the following css:

/* menu */
#leftbar {
    width: 25%;
    float: left;
    background: #CCCCFF;
    border: thin solid #000000;
}
      

We just changed the border-style to 'solid', the background to '#CCCCFF' and the color to '#000000'. Now we have to add a new tag to tell that we want to override the default.css. We are doing this by adding the tag <forrest:css url="howTo.css"/> to our view.

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">
  	<forrest:css url="howTo.css"/>
    <forrest:hook name="leftbar">
      <forrest:contract name="nav-section"/>
    </forrest:hook>
    <forrest:contract name="content-main"/>   
  </forrest:view>  
</forrest:views>
      

Now you see a white page where the menu is sourrounded by a solid border with the defined background. As second example let us change as well the content-main by adding another hook <forrest:hook name="content"/> We need to add the new layout container to our howTo.css:

/* The actual content */
#content {
    margin-left: 25%;
    padding: 0 20px 0 20px;
    background: #B9D3EE;
}
      

Then we have to add the 'content-main' contract to the 'content' hook, the resulting view looks like:

<forrest:views xmlns:forrest="http://apache.org/forrest/templates/1.0" >
  <forrest:view type="xhtml">
  	<forrest:css url="howTo.css"/>
    <forrest:hook name="leftbar">
      <forrest:contract name="nav-section"/>
    </forrest:hook>
    <forrest:hook name="content">
      <forrest:contract name="content-main"/>
    </forrest:hook>  
  </forrest:view>  
</forrest:views>
      

We are now able to place contracts into layout container and add custom css to the view.

Congratulations you are now able to work with the view DSL. From here we recommend to read the following How-To's:

• Create your own contract implementation

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