Salesforce - Developer - Scheduleable


// Salesforce - Develop - Schedulable Apex

To run a scheduled job manually using the developer console:

TargetX_SRMb.RecheckAllContactsScheduler p = new TargetX_SRMb.RecheckAllContactsScheduler();

Notice that in the above code, we use dot instead of double underscore.

global class SomeClass implements Schedulable {
    global void execute(SchedulableContext ctx) {
        // awesome code here

To schedule an Apex class, log into Salesforce, go to the place where Salesforce
display a list of Apex classes, at the top, there is a button to schedule Apex
classes.  On this screen, we can select the Apex class to schedule, the time,
and possibly other parameters.

Salesforce schedules the class for execution at the time you specified.  However,
actual execution may be delayed based on service availability.  We can only have
100 scheduled jobs at one time.

The Apex Scheduler lets you delay execution so that you can run Apex classes at 
a specified time. This is ideal for daily or weekly maintenance tasks using 
Batch Apex. To take advantage of the scheduler, write an Apex class that 
implements the Schedulable interface, and then schedule it for execution on a 
specific schedule.

To invoke Apex classes to run at specific times, first implement the Schedulable 
interface for the class. Then, schedule an instance of the class to run at a 
specific time using the System.schedule method.

The class implements the Schedulable interface and must implement the only 
method that this interface contains, which is the execute method.

The parameter of this method is a SchedulableContext object. After a class has 
been scheduled, a CronTrigger object is created that represents the scheduled 
job. It provides a getTriggerId method that returns the ID of a CronTrigger 
API object.

This class queries for open opportunities that should have closed by the 
current date, and creates a task on each one to remind the owner to update 
the opportunity.

global class RemindOpptyOwners implements Schedulable {
    global void execute(SchedulableContext ctx) {
        List<Opportunity> opptys = [SELECT Id, Name, OwnerId, CloseDate 
            FROM Opportunity 
            WHERE IsClosed = False AND 
            CloseDate < TODAY];
        // Create a task for each opportunity in the list

You can schedule your class to run either programmatically or from the Apex 
Scheduler UI.

After you implement a class with the Schedulable interface, use the 
System.Schedule method to execute it. The System.Schedule method uses the 
user's timezone for the basis of all schedules, but runs in system mode—all 
classes are executed, whether or not the user has permission to execute the 

Use extreme care if you’re planning to schedule a class from a trigger. You 
must be able to guarantee that the trigger won’t add more scheduled job classes 
than the limit. In particular, consider API bulk updates, import wizards, mass 
record changes through the user interface, and all cases where more than one 
record can be updated at a time.

The System.Schedule method takes three arguments: a name for the job, a CRON 
expression used to represent the time and date the job is scheduled to run, 
and the name of the class.

RemindOpptyOwners reminder = new RemindOpptyOwners();
// Seconds Minutes Hours Day_of_month Month Day_of_week optional_year
String sch = '20 30 8 10 2 ?';
String jobID = System.schedule('Remind Opp Owners', sch, reminder);
To Schedule a Job from the UI:

1. You can also schedule a class using the user interface.

2. From the Developer Console click Apex Classes | Schedule Apex.

3. For the job name, enter something like Daily Oppty Reminder.

4. Click the lookup button next to Apex class and enter * for the search 
   term to get a list of all classes that can be scheduled. In the search 
   results, click the name of your scheduled class.

5. Select Weekly or Monthly for the frequency and set the frequency desired.

6. Select the start and end dates, and a preferred start time.

7. Click Save.
// Testing Scheduled Apex:

Just like with the other async methods we’ve covered so far, with Scheduled 
Apex you must also ensure that the scheduled job is finished before testing 
against the results. To do this, use startTest and stopTest again around the 
System.schedule method, to ensure processing finishes before continuing with
our test.

private class RemindOppyOwnersTest {

    // Dummy CRON expression: midnight on March 15.
    // Because this is a test, job executes
    // immediately after Test.stopTest().
    public static String CRON_EXP = '0 0 0 15 3 ? 2022';

    static testmethod void testScheduledJob() {

        // Create some out of date Opportunity records
        List<Opportunity> opptys = new List<Opportunity>();
        Date closeDate =;
        for (Integer i=0; i<10; i++) {
            Opportunity o = new Opportunity(
                Name = 'Opportunity ' + i,
                CloseDate = closeDate,
                StageName = 'Prospecting'
        insert opptys;

        // Get the IDs of the opportunities we just inserted
        Map<Id, Opportunity> opptyMap = new Map<Id, Opportunity>(opptys);
        List<Id> opptyIds = new List<Id>(opptyMap.keySet());

        // Schedule the test job
        String jobId = System.schedule('ScheduledApexTest',
            new RemindOpptyOwners());         
        // Verify the scheduled job has not run yet.
        List<Task> lt = [SELECT Id 
            FROM Task 
            WHERE WhatId IN :opptyIds];
        System.assertEquals(0, lt.size(), 'Tasks exist before job has run');
        // Stopping the test will run the job synchronously

        // Now that the scheduled job has executed,
        // check that our tasks were created
        lt = [SELECT Id 
            FROM Task 
            WHERE WhatId IN :opptyIds];
            'Tasks were not created');


global class DailyLeadProcessor implements Schedulable {
    global void execute(SchedulableContext ctx) {
        for (Lead[] leads : [SELECT NAME FROM LEAD WHERE LeadSource = NULL]) {
            for (Lead lead : leads) {
                lead.LeadSource = 'Dreamforce';
            update leads;

public class DailyLeadProcessorTest {
    static void setup() {
        List<Lead> leads = new List<Lead>();
        for (Integer i = 0; i < 200; i++) {
            leads.add(new Lead(FirstName = 'KhaiTest', LastName = 'KhaiTest', Company = 'KhaiTest'));
        insert leads;
    static testmethod void testDailyLeadProcessor() {
        String sch = '0 0 0 15 3 ? 2022';
        DailyLeadProcessor schedulableObject = new DailyLeadProcessor();
        String jobID = System.schedule('Remind Opp Owners', sch, schedulableObject);
        List<Lead> leads = [SELECT NAME FROM LEAD WHERE LeadSource = NULL];
        System.assertEquals(200, leads.size());
        leads = [SELECT NAME FROM LEAD WHERE LeadSource = 'Dreamforce'];
        System.assertEquals(200, leads.size());
// Schedulable Apex Job - Things to remember:

1. You can only have 100 scheduled Apex jobs at one time and there are maximum 
   number of scheduled Apex executions per a 24-hour period. 

2. Use extreme care if you’re planning to schedule a class from a trigger. You 
   must be able to guarantee that the trigger won’t add more scheduled jobs 
   than the limit.

3. Synchronous Web service callouts are not supported from scheduled Apex. To be 
   able to make callouts, make an asynchronous callout by placing the callout 
   in a method annotated with @future(callout=true) and call this method from 
   scheduled Apex. However, if your scheduled Apex executes a batch job, 
   callouts are supported from the batch class.
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