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 Video Library
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
View Events Video Library
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
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

Integrating PostgreSQL Databases with ANF: Join this workshop to learn how to create a PostgreSQL server using Instaclustr’s managed service

Mobile Database Essentials: Assess data needs, storage requirements, and more when leveraging databases for cloud and edge applications.

Monitoring and Observability for LLMs: Datadog and Google Cloud discuss how to achieve optimal AI model performance.

Automated Testing: The latest on architecture, TDD, and the benefits of AI and low-code tools.

Related

  • How To Get and Set PDF Form Fields in Java
  • Micro Frontends for Quarkus Microservices
  • Building AI Applications With Java and Gradle
  • Demystifying Project Loom: A Guide to Lightweight Threads in Java

Trending

  • Automate Migration Assessment With XML Linter
  • Next.js vs. Gatsby: A Comprehensive Comparison
  • What You Must Know About Rate Limiting
  • Breaking Free From the Cloud With Kamal: Just Enough Orchestration for Your Apps
  1. DZone
  2. Coding
  3. Java
  4. Java 8: Lambda Expressions vs Auto Closeable

Java 8: Lambda Expressions vs Auto Closeable

Mark Needham user avatar by
Mark Needham
·
Mar. 03, 14 · Interview
Like (0)
Save
Tweet
Share
7.19K Views

Join the DZone community and get the full member experience.

Join For Free

If you used earlier versions of Neo4j via its Java API with Java 6 you probably have code similar to the following to ensure write operations happen within a transaction:

public class StylesOfTx
{
    public static void main( String[] args ) throws IOException
    {
        String path = "/tmp/tx-style-test";
        FileUtils.deleteRecursively(new File(path));
 
        GraphDatabaseService db = new GraphDatabaseFactory().newEmbeddedDatabase( path );
 
        Transaction tx = db.beginTx();
        try 
        {
            db.createNode();
            tx.success();
        } 
        finally 
        {
            tx.close();
        }
    }
}

In Neo4j 2.0 Transaction started extending AutoCloseable which meant that you could use ‘try with resources’ and the ‘close’ method would be automatically called when the block finished:

public class StylesOfTx
{
    public static void main( String[] args ) throws IOException
    {
        String path = "/tmp/tx-style-test";
        FileUtils.deleteRecursively(new File(path));
 
        GraphDatabaseService db = new GraphDatabaseFactory().newEmbeddedDatabase( path );
 
        try ( Transaction tx = db.beginTx() )
        {
            Node node = db.createNode();
            tx.success();
        }
    }
}

This works quite well although it’s still possible to have transactions hanging around in an application when people don’t use this syntax – the old style is still permissible.

In Venkat Subramaniam’s Java 8 book he suggests an alternative approach where we use a lambda based approach:

public class StylesOfTx
{
    public static void main( String[] args ) throws IOException
    {
        String path = "/tmp/tx-style-test";
        FileUtils.deleteRecursively(new File(path));
 
        GraphDatabaseService db = new GraphDatabaseFactory().newEmbeddedDatabase( path );
 
        Db.withinTransaction(db, neo4jDb -> {
            Node node = neo4jDb.createNode();
        });
    }
 
    static class Db {
        public static void withinTransaction(GraphDatabaseService db, Consumer<GraphDatabaseService> fn) {
            try ( Transaction tx = db.beginTx() )
            {
                fn.accept(db);
                tx.success();
            }
        }
    }
}

The ‘withinTransaction’ function would actually go on GraphDatabaseService or similar rather than being on that Db class but it was easier to put it on there for this example.

A disadvantage of this style is that you don’t have explicit control over the transaction for handling the failure case – it’s assumed that if ‘tx.success()’ isn’t called then the transaction failed and it’s rolled back. I’m not sure what % of use cases actually need such fine grained control though.

Brian Hurt refers to this as the ‘hole in the middle pattern‘ and I imagine we’ll start seeing more code of this ilk once Java 8 is released and becomes more widely used.

Java (programming language)

Published at DZone with permission of Mark Needham, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Related

  • How To Get and Set PDF Form Fields in Java
  • Micro Frontends for Quarkus Microservices
  • Building AI Applications With Java and Gradle
  • Demystifying Project Loom: A Guide to Lightweight Threads in Java

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

  • 3343 Perimeter Hill Drive
  • Suite 100
  • Nashville, TN 37211
  • support@dzone.com

Let's be friends: