DZone
Java Zone
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
  • Refcardz
  • Trend Reports
  • Webinars
  • Zones
  • |
    • Agile
    • AI
    • Big Data
    • Cloud
    • Database
    • DevOps
    • Integration
    • IoT
    • Java
    • Microservices
    • Open Source
    • Performance
    • Security
    • Web Dev
DZone > Java Zone > Groovy Goodness: Making Sure Closeable Objects Are Closed [Snippet]

Groovy Goodness: Making Sure Closeable Objects Are Closed [Snippet]

See how Groovy handles classes and objects that implement the Closeable interface and how you can ensure your closed methods are invoked.

Hubert Klein Ikkink user avatar by
Hubert Klein Ikkink
·
Oct. 20, 17 · Java Zone · Code Snippet
Like (1)
Save
Tweet
9.99K Views

Join the DZone community and get the full member experience.

Join For Free

If a class implements the Closeable interface, Groovy adds the withCloseable method to the class. The withCloseable method has a closure as an argument. The code in the closure is executed and then the implementation of the close method of the Closeable interface is invoked. The Closeable object is passed as an argument to the closure so we can refer to it inside the closure.

In the following example, we have two objects that implement the Closeable interface. By using withCloseable, we know for sure the close method is invoked after all the code in the closure is executed:

@Grab(group='org.apache.httpcomponents', module='httpclient', version='4.5.3')
import org.apache.http.impl.client.HttpClientBuilder
import org.apache.http.client.methods.HttpGet

// HttpClientBuilder.create().build() returns a CloseableHttpClient
// that implements the Closeable interface. Therefore we can use
// the withCloseable method to make sure the client is closed
// after the closure code is executed. 
HttpClientBuilder.create().build().withCloseable { client ->
    final request = new HttpGet('http://www.mrhaki.com')

    // The execute method returns a CloseableHttpResponse object
    // that implements the Closeable interface. We can use
    // withCloseable method to make sure the response is closed
    // after the closure code is executed.
    client.execute(request).withCloseable { response ->
        assert response.statusLine.statusCode == 200
    }
}


Written with Groovy 2.4.12.

Groovy (programming language) Object (computer science)

Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Popular on DZone

  • A First Look at CSS When and Else Statements
  • Migrating From Heroku To Render
  • Upsert in SQL: What Is an Upsert, and When Should You Use One?
  • Why Performance Projects Fail

Comments

Java Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • MVB Program
  • 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
  • +1 (919) 678-0300

Let's be friends:

DZone.com is powered by 

AnswerHub logo