jade4j - a jade implementation written in Java

jade4j's intention is to be able to process jade templates in Java without the need of a JavaScript environment, while being fully compatible with the original jade syntax.

Example
Syntax
Usage
Simple static API
Full API
Expressions
Reserved Words
Framework Integrations
Authors
License

Example

index.jade

!!! 5
html
  head
    title= pageName
  body
    ol#books
      for book in books
        if book.available
          li #{book.name} for #{book.price} €

Java model

List<Book> books = new ArrayList<Book>();
books.add(new Book("The Hitchhiker's Guide to the Galaxy", 5.70, true));
books.add(new Book("Life, the Universe and Everything", 5,60, false));
books.add(new Book("The Restaurant at the End of the Universe", 5.40, true));

Map<String, Object> model = new HashMap<String, Object>();
model.put("books", books);
model.put("pageName", "My Bookshelf")

Running the above code through String html = Jade4J.render("./index.jade", model) will result in the following output:

<!DOCTYPE html>
<html>
  <head>
    <title>My Bookshelf</title>
  </head>
  <body>
    <ol id="books">
      <li>The Hitchhiker's Guide to the Galaxy for 5,70 €</li>
      <li>The Restaurant at the End of the Universe for 5,40 €</li>
    </ol>
  </body>
</html>

Syntax

We have put up an interactive jade documentation.

See also the original visionmedia/jade documentation.

Usage

via Maven

As of release 0.4.1, we have changed maven hosting to sonatype. Using Github Maven Repository is no longer required.

Please be aware that we had to change the group id from 'de.neuland' to 'de.neuland-bfi' in order to meet sonatype conventions for group naming.

Just add following dependency definitions to your pom.xml.

<dependency>
  <groupId>de.neuland-bfi</groupId>
  <artifactId>jade4j</artifactId>
  <version>0.4.1</version>
</dependency>

Build it yourself

Clone this repository ...

git clone https://github.com/neuland/jade4j.git

... build it using maven ...

cd jade4j
mvn install

... and use the jade4j-0.x.x.jar located in your target directory.

Simple static API

Parsing template and generating template in one step.

String html = Jade4J.render("./index.jade", model);

If you use this in production you would probably do the template parsing only once per template and call the render method with different models.

JadeTemplate template = Jade4J.getTemplate("./index.jade");
String html = Jade4J.render(template, model);

Streaming output using a java.io.Writer

Jade4J.render(template, model, writer);

Full API

If you need more control you can instantiate a JadeConfiguration object.

JadeConfiguration config = new JadeConfiguration();

JadeTemplate template = config.getTemplate("index");

Map<String, Object> model = new HashMap<String, Object>();
model.put("company", "neuland");

config.renderTemplate(template, model);

Caching

The JadeConfiguration handles template caching for you. If you request the same unmodified template twice you'll get the same instance and avoid unnecessary parsing.

JadeTemplate t1 = config.getTemplate("index.jade");
JadeTemplate t2 = config.getTemplate("index.jade");
t1.equals(t2) // true

You can clear the template and expression cache by calling the following:

config.clearCache();

For development mode, you can also disable caching completely:

config.setCaching(false);

Output Formatting

By default, Jade4J produces compressed HTML without unneeded whitespace. You can change this behaviour by enabling PrettyPrint:

config.setPrettyPrint(true);

Jade detects if it has to generate (X)HTML or XML code by your specified doctype.

If you are rendering partial templates that don't include a doctype jade4j generates HTML code. You can also set the mode manually:

config.setMode(Jade4J.Mode.HTML);   // <input checked>
config.setMode(Jade4J.Mode.XHTML);  // <input checked="true" />
config.setMode(Jade4J.Mode.XML);    // <input checked="true"></input>

Filters

Filters allow embedding content like markdown or coffeescript into your jade template:

script
  :coffeescript
    sayHello -> alert "hello world"

will generate

<script>
  sayHello(function() {
    return alert("hello world");
  });
</script>

jade4j comes with a plain and cdata filter. plain takes your input to pass it directly through, cdata wraps your content in <![CDATA[...]]>. You can add your custom filters to your configuration.

config.setFilter("coffeescript", new CoffeeScriptFilter());

To implement your own filter, you have to implement the Filter Interface. If your filter doesn't use any data from the model you can inherit from the abstract CachingFilter and also get caching for free. See the neuland/jade4j-coffeescript-filter project as an example.

Helpers

If you need to call custom java functions the easiest way is to create helper classes and put an instance into the model.

public class MathHelper {
    public long round(double number) {
        return Math.round(number);
    }
}

model.put("math", new MathHelper());

Note: Helpers don't have their own namespace, so you have to be carefull not to overwrite them with other variables.

p= math.round(1.44)

Model Defaults

If you are using multiple templates you might have the need for a set of default objects that are available in all templates.

Map<String, Object> defaults = new HashMap<String, Object>();
defaults.put("city", "Bremen");
defaults.put("country", "Germany");
defaults.put("url", new MyUrlHelper());
config.setSharedVariables(defaults);

Template Loader

By default, jade4j searches for template files in your work directory. By specifying your own FileTemplateLoader, you can alter that behavior. You can also implement the TemplateLoader interface to create your own.

TemplateLoader loader = new FileTemplateLoader("/templates/", "UTF-8");
config.setTemplateLoader(loader);

Expressions

The original jade implementation uses JavaScript for expression handling in if, unless, for, case commands, like this

book = {"price": 4.99, "title": "The Book"}
if book.price < 5.50 && !book.soldOut
  p.sale special offer: #{book.title}

each author in ["artur", "stefan", "michael"]
  h2= author

As of version 0.3.0, jade4j uses JEXL instead of OGNL for parsing and executing these expressions.

We decided to switch to JEXL because its syntax and behavior is more similar to ECMAScript/JavaScript and so closer to the original jade.js implementation. JEXL runs also much faster than OGNL. In our benchmark, it showed a performance increase by factor 3 to 4.

We are using a slightly modified JEXL version which to have better control of the exception handling. JEXL now runs in a semi-strict mode, where non existing values and properties silently evaluate to null/false where as invalid method calls lead to a JadeCompilerException.

Reserved Words

JEXL comes with the three builtin functions new, size and empty. For properties with this name the . notation does not work, but you can access them with [].

book = {size: 540}
book.size // does not work
book["size"] // works

You can read more about this in the JEXL documentation.

Framework Integrations

If you want to use jade4j with Spring check out our neuland/spring-jade4j project.

Authors

Artur Tomas / atomiccoder
Stefan Kuper / planetk
Michael Geers / naltatis

Special thanks to TJ Holowaychuk the creator of jade!

License

The MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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jade4j's Introduction