Apache Velocity - 1.1

Extension Id

com.castsoftware.java.velocity

What’s new?

Please see Apache Velocity - 1.1 - Release Notes for more information.

Description

This extension provides support for Apache Velocity Framework. Apache Velocity is a Java-based templating engine, used to create dynamic web pages by parsing data model to template.

In what situation should you install this extension?

If your Java application uses the Apache Velocity Framework.

Technology support

Component Version Supported Supported Technology
velocity-engine-core 2.x ✅ JAVA
velocity-tools-view 3.x ✅ JAVA
spring-velocity-support 2.x ✅ JAVA
spring-context-support <= 4.3.x ✅ JAVA
spring-webmvc <= 4.3.x ✅ JAVA

Compatibility

Core release Supported
≥ 8.3.x ✅

Download and installation instructions

The extension will not be automatically downloaded and installed in CAST Console. If you need to use it, you should manually install the extension using the Application - Extensions interface.

What results can you expect?

Objects

Icon Description
Java Velocity VTL Parameter
Java Velocity Call To VTLContext
Link Type Source and destination of link Supported Velocity Engine Core Methods
relyonLink Between Java Velocity VTL Parameter and respective Context JAVA class.
Velocity Engineorg.apache.velocity.app.Velocity.mergeTemplate
org.apache.velocity.app.VelocityEngine.mergeTemplate
org.apache.velocity.Template.merge
org.apache.velocity.app.Velocity.evaluate
org.apache.velocity.app.VelocityEngine.evaluate

Velocity Toolsorg.apache.velocity.tools.view.VelocityViewServlet.mergeTemplate
org.apache.velocity.tools.view.VelocityLayoutServlet.mergeTemplate
org.apache.velocity.tools.view.VelocityView.merge

Velocity Springorg.springframework.ui.velocity.VelocityEngineUtils.mergeTemplateIntoString
org.springframework.ui.velocity.VelocityEngineUtils.mergeTemplate
org.apache.velocity.spring.VelocityEngineUtils.mergeTemplateIntoString
org.apache.velocity.spring.VelocityEngineUtils.mergeTemplate
org.springframework.web.servlet.view.velocity.VelocityView.mergeTemplate
relyonLink Between Java Velocity VTL Parameter and respective Context JAVA class. org.apache.velocity.tools.view.VelocityViewServlet.getTemplate
org.apache.velocity.app.Velocity.getTemplate
org.apache.velocity.app.VelocityEngine.getTemplate
org.apache.velocity.tools.view.VelocityView.getTemplate
org.apache.velocity.context.Context.put
org.apache.velocity.VelocityContext.put
org.apache.velocity.context.AbstractContext.put

NOTE: Java Velocity VTL Parameter object is created, only if the above APIs are called from overridden handleRequest method of VelocityViewServlet/VelocityLayoutServlet derived class.
callLink Between HTML source code objects and Java Velocity Call To VTLContext objects.
callLink Between Java Velocity Call To VTLContext objects and JAVA methods.

Code Examples

Velocity Engine Core

Velocity Engine code - Test6.java 
package test.velocity;

import org.apache.velocity.app.Velocity;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.context.Context;

import java.io.Writer;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collection;

import bean.Product;

class Test6 {

    public Test6() throws Exception {

        Velocity.init("src/main/java/velocity.properties");

        Context context = new VelocityContext();

        final Collection<Product> products = new ArrayList<>();
        //context.put("test", "test");

        products.add(new Product("Widget", 12.99));
        products.add(new Product("Wotsit", 13.99));
        products.add(new Product("Thingy", 11.99));

        context.put("products", products);

        Template template2 = Velocity.getTemplate("Test7.vm");

        Writer writer2 = new StringWriter();
        template2.merge(context, writer2);
        System.out.println(writer2.toString());
    }
}
Context Class - product.java 
package bean;

public class Product {

    private String name;
    private double price;

    public Product(String aName, double aPrice) {
        name = aName;
        price = aPrice;
    }

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }

    public void setName(String val) {
        name = val;
    }

    public void setPrice(double val) {
        price = val;
    }

    public String getNameAndPrice() {
        return "Name: " + getName() + " Price: " + getPrice();
    }
}
Velocity Template - Test7.vm 
#macro (writeTable $productList)
    #set ($rowCount = 1)
    #foreach($product in $productList)
    #if ($rowCount % 2 == 0)
        #set ($bgcolor = "#FFFFFF")
    #else
        #set ($bgcolor = "#CCCCCC")
    #end
        <tr>
            <td bgcolor="$bgcolor">$product.name</td>
            <td bgcolor="$bgcolor">$product.price</td>
        </tr>
        #set ($rowCount = $rowCount + 1)
    #end
#end


<html>
    <head>
        <title>Macros Test</title>
    </head>
    <body>
        <table>
            #writeTable($products)
        </table>
    </body>
</html>

Velocity Tools View

VelocityViewServlet - ProductServlet.java 
package com.test.apache.velocity.servlet;

import com.test.apache.velocity.model.Product;
import com.test.apache.velocity.service.ProductService;
import org.apache.velocity.Template;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.view.VelocityViewServlet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

public class ProductServlet extends VelocityViewServlet {

    ProductService service = new ProductService();

    @Override
    public Template handleRequest(HttpServletRequest request, HttpServletResponse response, Context context) {

        Logger logger= LoggerFactory.getLogger(ProductServlet.class);

        List<Product> products = service.getProducts();

        context.put("products", products);

        Template template = null;

        try {
            template = getTemplate("templates/index.vm");
            response.setHeader("Template Returned", "Success");
        } catch (Exception e) {
            logger.error("Error while reading the template ", e);
        }

        return template;

    }
}
Context Class - Product.java 
package com.test.apache.velocity.model;

public class Product {

    private String name;
    private double price;

    public Product(String name, double price) {
        this.name = name;
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Product{" + "name='" + name + '\'' + ", price=" + price + '}';
    }
}
Velocity Template - index.vm 
<HTML>
<HEAD>
    <TITLE>Online Electronic Store</TITLE>
    <style>
        body {background-color: powderblue;}
        h1   {color: blue;}
        p    {color: red;}
        table.gridtable {
            font-family: verdana,arial,sans-serif;
            font-size:11px;
            color:#333333;
            border-width: 1px;
            border-color: #666666;
            border-collapse: collapse;
        }
        table.gridtable th {
            border-width: 1px;
            padding: 8px;
            border-style: solid;
            border-color: #666666;
            background-color: #dedede;
        }
        table.gridtable td {
            border-width: 1px;
            padding: 8px;
            border-style: solid;
            border-color: #666666;
            background-color: #ffffff;
        }

    </style>

</HEAD>
<BODY>
<CENTER>
    <h1>Today's Offers</h1>
    <BR/>
    <BR/>
    <h2>$products.size() Products on Sale!</h2>
    <BR/>
    We are proud to offer these fine products
    at these amazing prices.
    <BR/>
    <BR/>
    #set( $count = 1 )
    <TABLE class="gridtable">
        <TR>
            <TH>Serial #</TH><TH>Product Name</TH><TH>Price</TH>
        </TR>
        #foreach( $product in $products )
            <TR>
                <TD>$count()</TD>
                <TD>$product.getName()</TD>
                <TD>$product.getPrice()</TD>
            </TR>
            #set( $count = $count + 1 )
        #end
    </TABLE>
    <BR/>
</CENTER>

</BODY>
</HTML>