jooby: rocker module

1. Rocker

Rocker is a Java 8 optimized, memory efficient, speedy template engine producing statically typed, plain java objects.

1.1. Usage

1) Add the dependency:

Maven

Gradle

<dependency>
  <groupId>io.jooby</groupId>
  <artifactId>jooby-rocker</artifactId>
  <version>3.0.10</version>
</dependency>

implementation 'io.jooby:jooby-rocker:3.0.10'

2) Configure code generator

Maven

Gradle

<plugin>
    <groupId>com.fizzed</groupId>
    <artifactId>rocker-maven-plugin</artifactId>
    <version>1.4.0</version>
    <configuration>
        <templateDirectory>src/rocker</templateDirectory>
    </configuration>
    <executions>
        <execution>
            <id>generate-rocker-templates</id>
            <phase>generate-sources</phase>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
</plugin>

plugins {
  id "com.fizzed.rocker" version "1.4.0"
}

sourceSets {
    main {
        rocker {
            srcDir('src/rocker')
        }
    }
}

Complete code generator options are available here

3) Write your templates inside the src/rocker/views folder

src/rocker/views/index.rocker.html

@args (String message)

<p>Hello @message!</p>

4) Install and use rocker templates

Java

Kotlin

import io.jooby.rocker.RockerModule;

{
  install(new RockerModule());              (1)

  get("/", ctx -> {
    return views.index.template("Rocker");  (2)
  });
}

import io.jooby.rocker.RockerModule

{
  install(RockerModule())                   (1)

  get("/") {
    views.index.template("Rocker")          (2)
  }
}

1	Install Rocker
2	Returns a rocker view

1.2. Options

Rocker uses a byte buffer to render a view. Default byte buffer size is 4k. To change the buffer size:

Java

Kotlin

import io.jooby.rocker.RockerModule;

{
  install(new RockerModule().bufferSize(1024));
}

import io.jooby.rocker.RockerModule

{
  install(RockerModule().bufferSize(1024)
}

You can reuse/recycle the buffer using a thread-local approach by setting reuseBuffer(true):

Java

Kotlin

import io.jooby.rocker.RockerModule;

{
  install(new RockerModule().reuseBuffer(true));
}

import io.jooby.rocker.RockerModule

{
  install(RockerModule().reuseBuffer(true)
}

Use with caution due it creates a buffer per thread memory consumption might be high. This technique works when the number of available threads is low enough (like the number of available processors).