Salesforce Chained Queueable Apex Class

ChainedQueueable.cls

public without sharing class ChainedQueueable implements Queueable {

    private Set<Id> ids;

    public ChainedQueueable(Set<Id> ids) {
        this.ids = ids;
    }

    public void execute(QueueableContext context) {

        if (ids.size() == 0) {
            return;
        }

        // get next id 
        Id recordId = getNextId();

        // do something with the record

        // create new job and process next record
        processNextRecord();
    }

    private void processNextRecord() 
    {
        enqueueJob(this.ids);
    }

    public static void enqueueJob(Set<Id> ids) {

        if (ids.size() == 0) {
            return;
        }

        // create next job
        ChainedQueueable job = new ChainedQueueable(ids);

        // queue next job
        Id jobId = System.enqueueJob(job);

        System.debug(jobId);
    }

    private Id getNextId() {

        // get next record Id
        Id recordId;
        for(Id item : ids) {
            recordId = item;
            break;
        }

        // remove recordId
        ids.remove(recordId);

        return recordId;
    }
}