Queueable Apex Job

Queueable job that add job to the queue and each job runs when system resources become available.

Apex processes that run for a long time, such as extensive database operations or external Web service callouts, you can run them asynchronously by implementing the Queueable interface and adding a job to the Apex job queue Queueable job runs in the background in its own thread and doesn’t delay the execution of your main Apex logic. Each queued job runs when system resources become available. Queueable interface methods helps in increasing some governor limits are higher than for synchronous Apex, such as heap size limits.

Read: How to Create Visualforce Page in Salesforce

Queueable jobs and future methods both are queued for execution, but Queueable jobs provide you with these additional benefits.

• Getting an ID for your job:
• When you submit your job by invoking the System. Enqueue Job method, the method returns the ID of the new job.
• Using non-primitive types:
• It contain some variables of non-primitive data types, such as sObjects or custom Apex types. Those objects can be accessed when the job executes.
• Chaining jobs: You can chain one job to another job by starting a second job from a running job. Chaining jobs is useful if you need to do some processing that depends on another process to have run first.

Things to Remember

Read: What is Escalation Rules? Salesforce Escalation Rules Tutorial Guide

1. The execution of a queued job counts once against the shared limit for asynchronous Apex method executions.
2. enqueue Job can add up to 50 jobs to the queue with in a single transaction.
3. When chaining jobs, you can add only one job from an executing job with System. Enqueue Job, which means that only one child job can exist for each parent Queueable job.
4. No limit is enforced on the depth of chained jobs, which means that you can chain one job to another job and repeat this process with each new child job to link it to a new child job. However, for Developer Edition and Trial orgs, the maximum stack depth for chained jobs is 5.

Sample Code:

public class QueueableExample implements Queueable {
public void execute(QueueableContext context) {
        Account a = new Account(Name='Daniel',Phone='(+12) 354-45345');
insert a;        
    }
}

Debug

ID jobID = System.enqueueJob(new QueueableExample());
system.debug(jobId);

 

Read: Salesforce Integration with SharePoint and LinkedIn