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How do I run a Velocity template?
Simply put, here are the steps we need to follow for any typical velocity application:Initialize the velocity engine.Read the template.Put the data model in context object.Merge the template with context data and render the view.
What are Vlocity templates?
¶ Velocity is a Java-based template engine. It permits anyone to use a simple yet powerful template language to reference objects defined in Java code.
What is Velocity document?
Velocity is the next-generation Minecraft: Java Edition proxy. Velocity is built to be highly compatible with server software like Paper, Sponge, and modding platforms such as Minecraft Forge, while also exposing a rich plugin API and providing unparalleled scalability. Note.
What is Velocity script?
Velocity scripting is a scripting language that marketers can use to craft dynamic content. The language is rooted in Java and lets you control HTML content. At a high level, Velocity scripting works in two ways: You can use it to generate source code. You can integrate it with other systems.
How do you debug a Velocity template?
vm file. Then from the template you want to debug, you can simply add #showDebugPopup() to the bottom of the template you want to debug, and it will pop up a window with debugging information. You'll need to remove that invocation before you go to production.
What is Velocity context?
VelocityContext(Context innerContext) Chaining constructor, used when you want to wrap a context in another. VelocityContext(Map
How do you find the velocity?
Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.
What is velocity log?
The velocity log was designed as an aid to the geophysicist to deter- mine velocity layering in the earth and to provide fast, accurate and economical vertical travel time data. After a number of logs had been made, studies were carried out on their use ia correlating strata in ad- jacent wells.
What are VM files in Java?
Developer file used by Velocity, a Java-based template engine; written using the Velocity Template Language (VTL); contains VTL statements inserted in a normal text document; often used for auto-generating Web source code and class skeletons.
What is the use of Velocity Engine in Java?
The Velocity Template Engine lets you render data from within applications and servlets. Primarily used to develop dynamic, servlet-based Websites, Velocity's clean separation of template and Java code makes it ideal for MVC Web development.
What is a scripted Email?
Email scripting is just what it sounds like: It's using a scripting language within outbound emails in order to provide dynamic content to recipients. In its simplest usage, email scripting can populate emails with current date or pricing information.
What are Marketo tokens?
Tokens in Marketo are special strings similar to shortcodes which are replaced by a separate piece of data at run time. There are several types of tokens available in Marketo, but only My Tokens can be edited via the API. My Tokens are child tokens which are local to a particular folder or program.
What does velocity do in a template?
Velocity will replace a variable reference in a template with the String representation of an object. If the object referenced by a variable is not a String object, Velocity calls its toString () method to render output. This is the default behavior; however, you can override the toString () method in the way that you want to show the output.
How does velocity work?
Velocity uses resource loaders to find templates to process. More than one resource loader can be configured in the Velocity.properties configuration file to be used with Velocity, and Velocity will search through them in order.
What is velocity in JSP?
Velocity is a combination of a template processing engine and a template language that is designed to work with other web application frameworks in place of JSP. You can also use Velocity for general-purpose template tasks, such as generating e-mail, static HTML files, or legacy data-integration files.
What does velocity use reflection for?
Velocity uses reflection to determine which methods are available in the objects in the context. If the variable is just a reference to the object itself, the Velocity engine will call the toString () method in the object and render it to the output.
Does velocity use its own syntax?
As we've already seen, Velocity uses its own syntax in templates so that the template content is completely separated from any additional code. In this section, we are going to go through the main syntax of the Velocity Templating Language (VTL).
Can velocity load external templates?
Velocity templates can load external templates or files, just like most page-oriented languages you may already be familiar with. The files or templates are found using the Velocity resource loader. To use them, there are two directives:
Does velocity have a reference?
Normally, Velocity will display a variable reference in the results, even if the variable doesn't exist in the context. This is because the reference could just be included in the original text. Here is a quick demonstration of this:
What is velocity software?
Velocity is a project of the Apache Software Foundation, charged with the creation and maintenance of open-source software related to the Apache Velocity Engine. All software created at the Velocity project is available under the Apache Software License and free of charge for the public.
What is velocity in Java?
Velocity is a Java-based template engine. It permits anyone to use a simple yet powerful template language to reference objects defined in Java code. When Velocity is used for web development, Web designers can work in parallel with Java programmers to develop web sites according to the Model-View-Controller (MVC) model, ...
What is Apache Foundation?
The Apache Software Foundation provides support for the Apache community of open-source software projects. The Apache projects are characterized by a collaborative, consensus based development process, an open and pragmatic software license, and a desire to create high quality software that leads the way in its field.
What is velocity template language?
The Velocity Template Language (VTL) is meant to provide the easiest, simplest, and cleanest way to incorporate dynamic content in a web page. Even a web page developer with little or no programming experience should soon be capable of using VTL to incorporate dynamic content in a web site.
What is velocity user guide?
The Velocity User Guide is intended to help page designers and content providers get acquainted with Velocity and the syntax of its simple yet powerful scripting language, the Velocity Template Language (VTL). Many of the examples in this guide deal with using Velocity to embed dynamic content in web sites, but all VTL examples are equally applicable to other pages and templates.
What is a VTL variable?
Variables are one type of reference that can refer to something defined in the Java code, or it can get its value from a VTL statement in the web page itself.
What is velocity in Java?
Velocity separates Java code from the web pages, making the web site more maintainable over the long run and providing a viable alternative to Java Server Pages (JSPs) or PHP. Velocity can be used to generate web pages, SQL, PostScript and other output from templates.
What does #stop do in a template?
The #stop directive stops any further rendering and execution of the template. This is true even when the directive is nested within another template accessed through #parse or located in a velocity macro. The resulting merged output will contain all the content up to the point the #stop directive was encountered. This is handy as an early exit from a template. For debugging purposes, you may provide a message argument (e.g. #stop ('$foo was not in context') ) that will be written to the logs (DEBUG level, of course) upon completion of the stop command.
What is #include in a template?
The #include script element allows the template designer to import a local file, which is then inserted into the location where the #include directive is defined. The contents of the file are not rendered through the template engine. For security reasons, the file to be included may only be under TEMPLATE_ROOT.
What are the types of references in VTL?
There are three types of references in the VTL: variables, properties and methods. As a designer using the VTL, you and your engineers must come to an agreement on the specific names of references so you can use them correctly in your templates.
3. Maven Dependencies
To work with Velocity, we need to add following dependencies to our Maven project:
4. Velocity Template Language
Velocity Template Language (VTL) provides the simplest and cleanest way of incorporating the dynamic content in a web page by using VTL references.
5. Velocity Servlet
The primary job of the Velocity Engine is to generate content based on a template.
6. Configuration
Let's now see how to configure the VelocityViewServlet in the web.xml.
7. Velocity Template
Velocity template is the place where all the view generation logic is written. These pages are written using Velocity Template Language (VTL):
8. Managing the Page Layout
Velocity provides a simple layout control and customizable error screens for Velocity Tool based application.
9. Conclusion
In this article, we have learned how Velocity is a useful tool for rendering the dynamic web pages. Also, we have seen different ways of using velocity provided servlets.
Overview
Separating Presentation from Java Code
- The Concern Slush antipattern occurs in applications when the business logic, application content, data access, look-and-feel, and navigation are all put together in a hard-to-maintain slush. An example of this would be a giant servlet that contains methods that make JDBC calls, intermingle the results with HTML markup, and then create JavaScript validation routines. It bec…
Velocity
- In this section, we're going to discuss how to use Velocity and primarily the Velocity language and API. We're going to cover: 1. What Velocity does, and how the engine works 2. Using Velocity's context 3. Using the Velocity GUI to run Velocity code outside the servlet container for debugging 4. The syntax and keywords of the Velocity Template Language (VTL) 5. Using Velocity from JS…
How Velocity Works
- Velocity is a processing engine that is fed a context, which contains name-value pairs of variable names and Java objects, and a templatethat usually contains HTML or XML interspersed with Velocity markup. The context is merged with the template to create output, which is then displayed to the end user or written to a file. The template contains va...
The Velocity Templating Language
- As we've already seen, Velocity uses its own syntax in templates so that the template content is completely separated from any additional code. In this section, we are going to go through the main syntax of the Velocity Templating Language (VTL).
Using The Velocity Engine from Java
- We are going to discuss how to evaluate Velocity templates from inside a Java application. There are several different ways of doing this. We will start with the most general case, applicable to all Java applications. It uses the org.apache.velocity.app.Velocityclass to evaluate a Velocity template. Web applications can use Velocity as a presentation layer. We'll using the Velocity tag …
Jsp and Velocity
- JSP can be used with Velocity through the Velocity tag library. If Velocity syntax matches your project needs better than JSP scriptlets or the expression language, it's a simple task to integrate Velocity with your existing JSP-based application. The Velocity tag library doesn't depend on Struts or any other MVC frameworks to work. There is only one tag for Velocity – the contents o…
Creating The JavaEdge RSS Feed with Velocity
- We have several requirements for this piece of the JavaEdge application: 1. Create an RSS feed that reflects the last stories to be added to JavaEdge 2. Include all of the stories on the JavaEdge home page 3. Use Velocity to create the solution, so we can demonstrate this clever tool 4. Follow the RSS 2.0 specification The first piece of the design puzzle is to determine how we are going t…
Summary
- In this chapter, we've discussed how to use Velocity inside a Struts web application as a presentation layer. We've also shown how to use Velocity from any Java application as a template processing engine. We discussed the Velocity Template Language (VTL) in detail and gave examples for most VTL directives. We also covered Velocity macros, iterators, and logical opera…