sng2c/ERB.java

## bootstrap.rb
require 'erb'
require 'ostruct'
require 'java'

# Renders an ERB template against a hashmap of variables.
# template should be a Java InputStream
def render(template, variables)
  context = OpenStruct.new(variables).instance_eval do
    variables.each do |k, v|
      instance_variable_set(k, v) if k[0] == '@'
    end

    def partial(partial_name, options={})
      new_variables = marshal_dump.merge(options[:locals] || {})
      Java::Pavo::ERB.render(partial_name, new_variables)
    end

    binding
  end
  ERB.new(template.to_io.read).result(context);
end

# Renders an ERB template wrapped in an ERB layout.
# template and layout should both be Java InputStreams
def render_with_layout(template, layout, variables)
  render(layout, variables) do
    render(template, variables)
  end
end

## ERB.java
package pavo;

import java.io.*;
import java.util.*;
import javax.script.*;

public class ERB {

    static ScriptEngine jruby = initializeJRuby();

    static ScriptEngine initializeJRuby() {
        try (InputStream bootstrap = ERB.class.getResourceAsStream("bootstrap.rb")) {
            ScriptEngine jruby = new ScriptEngineManager().getEngineByName("jruby");
            jruby.eval(new InputStreamReader(bootstrap));
            return jruby;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static InputStream openTemplate(String name) {
        return ERB.class.getResourceAsStream(name + ".erb");
    }

    public static String render(String template, Map<String,Object> variables) throws Exception {
        try (InputStream stream = openTemplate(template)) {
            return (String) ((Invocable)jruby).invokeFunction("render", stream, variables);
        }
    }

    /**
     * Render an ERB template wrapped in a ERB layout.
     */
    public static String render(String template, String layout, Map<String,Object> variables) throws Exception {
        try (InputStream templateStream = openTemplate(template);
                InputStream layoutStream = openTemplate(layout)) {
            return (String) ((Invocable)jruby).invokeFunction("render_with_layout",
                    templateStream, layoutStream, variables);
        }
    }

}

## hello.erb
Hello <%= @user %>

<%= partial("partial", :locals => {:city => "canberra"}) %>

## HelloController.java
package pavo;

import java.util.*;
import javax.ws.rs.*;

@Path("/")
public class HelloController {

    @GET
    public String hello() throws Exception {
        Map<String,Object> variables = new HashMap<>();
        variables.put("@title", "The Home Page");
        variables.put("@user", "Michael");
        return ERB.render("hello.erb", variables);
    }

}

## layout.erb
<html>
  <head><title><%= @title %></title></head>
  <body><%= yield %></body>
</html>

## partial.rb
<p>I am a partial. You are <%= @user %> in <%= city %>.</p>

## pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>au.gov.nla</groupId>
  <artifactId>erbtest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <properties>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>
  <build>
    <plugins>
      <plugin>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
  <dependencies>
    <dependency>
      <groupId>org.jruby</groupId>
      <artifactId>jruby-complete</artifactId>
      <version>1.7.0.RC1</version>
    </dependency>
    <dependency>
      <groupId>com.sun.jersey</groupId>
      <artifactId>jersey-servlet</artifactId>
      <version>1.17.1</version>
    </dependency>
  </dependencies>
</project>

## web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
  id="WebApp_ID" version="2.5">
  <servlet>
    <servlet-name>pavo</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
      <param-name>com.sun.jersey.config.property.packages</param-name>
      <param-value>pavo</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>pavo</servlet-name>
    <url-pattern>/*</url-pattern>
  </servlet-mapping>
</web-app>
	require 'erb'
	require 'ostruct'
	require 'java'

	# Renders an ERB template against a hashmap of variables.
	# template should be a Java InputStream
	def render(template, variables)
	context = OpenStruct.new(variables).instance_eval do
	variables.each do \|k, v\|
	instance_variable_set(k, v) if k[0] == '@'
	end

	def partial(partial_name, options={})
	new_variables = marshal_dump.merge(options[:locals] \|\| {})
	Java::Pavo::ERB.render(partial_name, new_variables)
	end

	binding
	end
	ERB.new(template.to_io.read).result(context);
	end

	# Renders an ERB template wrapped in an ERB layout.
	# template and layout should both be Java InputStreams
	def render_with_layout(template, layout, variables)
	render(layout, variables) do
	render(template, variables)
	end
	end
	package pavo;

	import java.io.*;
	import java.util.*;
	import javax.script.*;

	public class ERB {

	static ScriptEngine jruby = initializeJRuby();

	static ScriptEngine initializeJRuby() {
	try (InputStream bootstrap = ERB.class.getResourceAsStream("bootstrap.rb")) {
	ScriptEngine jruby = new ScriptEngineManager().getEngineByName("jruby");
	jruby.eval(new InputStreamReader(bootstrap));
	return jruby;
	} catch (Exception e) {
	throw new RuntimeException(e);
	}
	}

	public static InputStream openTemplate(String name) {
	return ERB.class.getResourceAsStream(name + ".erb");
	}

	public static String render(String template, Map<String,Object> variables) throws Exception {
	try (InputStream stream = openTemplate(template)) {
	return (String) ((Invocable)jruby).invokeFunction("render", stream, variables);
	}
	}

	/**
	* Render an ERB template wrapped in a ERB layout.
	*/
	public static String render(String template, String layout, Map<String,Object> variables) throws Exception {
	try (InputStream templateStream = openTemplate(template);
	InputStream layoutStream = openTemplate(layout)) {
	return (String) ((Invocable)jruby).invokeFunction("render_with_layout",
	templateStream, layoutStream, variables);
	}
	}

	}
	Hello <%= @user %>

	<%= partial("partial", :locals => {:city => "canberra"}) %>
	package pavo;

	import java.util.*;
	import javax.ws.rs.*;

	@Path("/")
	public class HelloController {

	@GET
	public String hello() throws Exception {
	Map<String,Object> variables = new HashMap<>();
	variables.put("@title", "The Home Page");
	variables.put("@user", "Michael");
	return ERB.render("hello.erb", variables);
	}

	}
	<html>
	<head><title><%= @title %></title></head>
	<body><%= yield %></body>
	</html>
	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>au.gov.nla</groupId>
	<artifactId>erbtest</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<properties>
	<maven.compiler.source>1.7</maven.compiler.source>
	<maven.compiler.target>1.7</maven.compiler.target>
	</properties>
	<build>
	<plugins>
	<plugin>
	<groupId>org.eclipse.jetty</groupId>
	<artifactId>jetty-maven-plugin</artifactId>
	</plugin>
	</plugins>
	</build>
	<dependencies>
	<dependency>
	<groupId>org.jruby</groupId>
	<artifactId>jruby-complete</artifactId>
	<version>1.7.0.RC1</version>
	</dependency>
	<dependency>
	<groupId>com.sun.jersey</groupId>
	<artifactId>jersey-servlet</artifactId>
	<version>1.17.1</version>
	</dependency>
	</dependencies>
	</project>
	<?xml version="1.0" encoding="UTF-8"?>
	<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">
	<servlet>
	<servlet-name>pavo</servlet-name>
	<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
	<init-param>
	<param-name>com.sun.jersey.config.property.packages</param-name>
	<param-value>pavo</param-value>
	</init-param>
	<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
	<servlet-name>pavo</servlet-name>
	<url-pattern>/*</url-pattern>
	</servlet-mapping>
	</web-app>