DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports Events Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones AWS Cloud
by AWS Developer Relations
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones
AWS Cloud
by AWS Developer Relations

Trending

  • How To Scan and Validate Image Uploads in Java
  • Implementing RBAC in Quarkus
  • Mainframe Development for the "No Mainframe" Generation
  • How To Become a 10x Dev: An Essential Guide
  1. DZone
  2. Coding
  3. Languages
  4. Groovy: Use @Canonical to Get Compiler-generated Equals, HashCode and ToString

Groovy: Use @Canonical to Get Compiler-generated Equals, HashCode and ToString

Jakub Holý user avatar by
Jakub Holý
·
Nov. 07, 11 · Interview
Like (0)
Save
Tweet
Share
4.55K Views

Join the DZone community and get the full member experience.

Join For Free

Groovy makes it extremely easy to create Java beans with getters, setters, equals, hashCode, and toString:

@groovy.transform.Canonical
class Call {
   def method
   def args

   /* // custom impl. reusing the auto-generated one:
   String toString() {
      _toString().replaceFirst("^.*?Call", "")
   }*/
}

You can then do:

// Auto-gen. constr. with positional arguments:
def call1 = new Call("someMethod", "someArgs")
def call2 = new Call(method: "someMethod", args: "someArgs")
assert call1.getMethod() == call1.method
assert call2.equals(call1)
assert ([call1, call2] as Set).size() == 1 // hashCode

As you might have noticed, you may provide your own implementation of toString and reuse the auto-generated toString by calling _toString().

References

JavaDoc for @Canonical. You can also use separately any of: @ToString. @EqualsAndHashCode, @TupleConstructor. And may be check also the other available AST annotations such as Immutable and Synchronized and perhaps also groovy.beans‘s Bindable and Vetoable annotations, if you need true Java Beans.

 

From http://theholyjava.wordpress.com/2011/11/02/groovy-use-canonical-to-get-compiler-generated-equals-hashcode-and-tostring/

Groovy (programming language)

Opinions expressed by DZone contributors are their own.

Trending

  • How To Scan and Validate Image Uploads in Java
  • Implementing RBAC in Quarkus
  • Mainframe Development for the "No Mainframe" Generation
  • How To Become a 10x Dev: An Essential Guide

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com

Let's be friends: