Welcome!

Machine Learning Authors: Carmen Gonzalez, Yeshim Deniz, Bob Gourley, Elizabeth White, Pat Romanski

Related Topics: Java IoT, Machine Learning

Java IoT: Article

Be Standard, Be Free: Use JSR-303 for Validation

No matter what type of application we develop, coding validations is our everyday task

No matter what type of application we develop, coding validations is our everyday task. For years we have used a big variety of techniques and frameworks for validation with success. However, since some time we have a standard Java for validation, the Bean Validation specification (JSR-303). The question is: is it worth writing (or rewriting) our validations using the Bean Validation standard? Is there some practical advantage in use JSR-303?

First, let's write a validator (constraint in Bean Validation nomenclature) and then let's use it in our code, to see what we are talking about.

Creating a JSR-303 Constraint
A JSR-303 constraint is just a plain Java annotation. For example, if we want to validate ISBNs, we have to create an @ISBN annotation like the next one:

package org.openxava.books.constraints;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import java.lang.annotation.*;
import javax.validation.*;
import org.openxava.books.constraints.impl.*;

@Constraint(validatedBy = ISBNValidator.class)
@Target({ METHOD, FIELD })
@Retention(RUNTIME)
public @interface ISBN {

String message() default
"{org.openxava.books.constraints.ISBN.message}";
Class[] groups() default { };
Class[] payload() default { };

}

The key part here is the @Constraint annotation. It marks this annotation as a constraint and indicates the validator class, ISBNValidator, that is the class with the validation logic:

package org.openxava.books.constraints.impl;

import javax.validation.*;
import org.openxava.books.constraints.*;

public class ISBNValidator implements ConstraintValidator<ISBN, String> {
    
    private static org.apache.commons.validator.ISBNValidator
validator =
        new org.apache.commons.validator.ISBNValidator();

    public void initialize(ISBN isbn) {        
    }

    public boolean isValid(String value, ConstraintValidatorContext ctx) { // The validation logic
        if (value == null || value.trim().equals("")) return true;
        return validator.isValid(value); // We simply delegate in commons validator
    }

}

The validator must implement ConstraintValidator, so it needs to have the initialize() and isValid() methods, the latter contains the validation logic. In this case we simply delegate in a validator from Apache Commons Validator project.

As we can see create a validator is pretty simple. Now, how can we use this validation in our application?

Using the Validator
The JSR-303 specification talks about how to define validators, but not about how they are used and behave in our application, this depends on the framework we are using JPA2 and JSF2 have Bean Validation integration, moreover many modern frameworks have support for JSR-303 as well. In this case we are going to develop a mini-application using the OpenXava framework that use the above @ISBN application. Don't panic, developing an OpenXava application is short (and sweet), given we only need to write the domain classes.

After creating a new OpenXava project (executing an ant target) we add the Author and Book classes to it.
Author.groovy:

package org.openxava.books.model

import javax.persistence.*
import org.openxava.model.*
import org.openxava.annotations.*

@Entity
class Author extends Identifiable {

   [email protected]
    String name
    
}

 

Book.groovy:

package org.openxava.books.model

import org.openxava.model.*;
import org.openxava.annotations.*;
import org.openxava.books.constraints.*;
import javax.persistence.*;

@Entity
class Book extends Identifiable {

   [email protected] @Column(length=60)
    String title
    
   [email protected](fetch=FetchType.LAZY)
   [email protected]
    Author author
    
   [email protected](length=10)
   [email protected]
    String isbn
    
}


Although we could write the classes with Java, we have chosen Groovy. Yes, Groovy Web Development without Grails is possible. However, the important point here is the @ISBN annotation in isbn property. We do not need more work to see the validation working. If we go to http://localhost:8080/Books/modules/Book, and we try to add a Book with an incorrect ISBN, we'll get something like this:

As we can see using the @ISBN validation in our application is a completely declarative task, so dead easy.

Why Should I Use Bean Validation?
Though JSR-303 is easy to use and versatile enough to meet our validation needs, really is not something spectacular, and possibly not much better than our current validation framework, so, why should we use it? Because it is supported by JPA2, JSF2, Spring Roo, Wicket, Tapestry, etc. in addition to be included as part of Java EE 6. Therefore, it gives us more freedom, because our code is less dependent from the application framework we are using, thus it's easier to migrate our code (at least the model part) from Wicket to Tapestry, or from Spring Roo to OpenXava.

Use the Bean Validation standard. Be free!

Resources

More Stories By Javier Paniza

Javier Paniza is the project lead for OpenXava project. He works as software developer at Gestión 400, a software company for public administration in Spain. He has been developing with Java Enterprise since 1998. Also he has been J2EE mentor for development teams in banking projects.

@CloudExpo Stories
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
New competitors, disruptive technologies, and growing expectations are pushing every business to both adopt and deliver new digital services. This ‘Digital Transformation’ demands rapid delivery and continuous iteration of new competitive services via multiple channels, which in turn demands new service delivery techniques – including DevOps. In this power panel at @DevOpsSummit 20th Cloud Expo, moderated by DevOps Conference Co-Chair Andi Mann, panelists will examine how DevOps helps to meet th...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
With billions of sensors deployed worldwide, the amount of machine-generated data will soon exceed what our networks can handle. But consumers and businesses will expect seamless experiences and real-time responsiveness. What does this mean for IoT devices and the infrastructure that supports them? More of the data will need to be handled at - or closer to - the devices themselves.
Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market across the USA and Europe, we work with a variety of customers from emerging startups to Fortune 1000 companies.
Financial Technology has become a topic of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 20th Cloud Expo at the Javits Center in New York, June 6-8, 2017, will find fresh new content in a new track called FinTech.
@DevOpsSummit at Cloud taking place June 6-8, 2017, at Javits Center, New York City, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long developm...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 20th Cloud Expo, which will take place on June 6-8, 2017 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 add...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
SYS-CON Events announced today that Juniper Networks (NYSE: JNPR), an industry leader in automated, scalable and secure networks, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Juniper Networks challenges the status quo with products, solutions and services that transform the economics of networking. The company co-innovates with customers and partners to deliver automated, scalable and secure network...
The age of Digital Disruption is evolving into the next era – Digital Cohesion, an age in which applications securely self-assemble and deliver predictive services that continuously adapt to user behavior. Information from devices, sensors and applications around us will drive services seamlessly across mobile and fixed devices/infrastructure. This evolution is happening now in software defined services and secure networking. Four key drivers – Performance, Economics, Interoperability and Trust ...
Cloud Expo, Inc. has announced today that Aruna Ravichandran, vice president of DevOps Product and Solutions Marketing at CA Technologies, has been named co-conference chair of DevOps at Cloud Expo 2017. The @DevOpsSummit at Cloud Expo New York will take place on June 6-8, 2017, at the Javits Center in New York City, New York, and @DevOpsSummit at Cloud Expo Silicon Valley will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
In recent years, containers have taken the world by storm. Companies of all sizes and industries have realized the massive benefits of containers, such as unprecedented mobility, higher hardware utilization, and increased flexibility and agility; however, many containers today are non-persistent. Containers without persistence miss out on many benefits, and in many cases simply pass the responsibility of persistence onto other infrastructure, adding additional complexity.
SYS-CON Events announced today that Hitachi Data Systems, a wholly owned subsidiary of Hitachi LTD., will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City. Hitachi Data Systems (HDS) will be featuring the Hitachi Content Platform (HCP) portfolio. This is the industry’s only offering that allows organizations to bring together object storage, file sync and share, cloud storage gateways, and sophisticated search an...
Automation is enabling enterprises to design, deploy, and manage more complex, hybrid cloud environments. Yet the people who manage these environments must be trained in and understanding these environments better than ever before. A new era of analytics and cognitive computing is adding intelligence, but also more complexity, to these cloud environments. How smart is your cloud? How smart should it be? In this power panel at 20th Cloud Expo, moderated by Conference Chair Roger Strukhoff, pane...
@GonzalezCarmen has been ranked the Number One Influencer and @ThingsExpo has been named the Number One Brand in the “M2M 2016: Top 100 Influencers and Brands” by Analytic. Onalytica analyzed tweets over the last 6 months mentioning the keywords M2M OR “Machine to Machine.” They then identified the top 100 most influential brands and individuals leading the discussion on Twitter.
SYS-CON Events announced today that Twistlock, the leading provider of cloud container security solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Twistlock is the industry's first enterprise security suite for container security. Twistlock's technology addresses risks on the host and within the application of the container, enabling enterprises to consistently enforce security policies, monitor...
@ThingsExpo has been named the Most Influential ‘Smart Cities - IIoT' Account and @BigDataExpo has been named fourteenth by Right Relevance (RR), which provides curated information and intelligence on approximately 50,000 topics. In addition, Right Relevance provides an Insights offering that combines the above Topics and Influencers information with real time conversations to provide actionable intelligence with visualizations to enable decision making. The Insights service is applicable to eve...
Multiple data types are pouring into IoT deployments. Data is coming in small packages as well as enormous files and data streams of many sizes. Widespread use of mobile devices adds to the total. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists will look at the tools and environments that are being put to use in IoT deployments, as well as the team skills a modern enterprise IT shop needs to keep things running, get a handle on all this data, and deli...