tshevchuk · September 4, 2024 13:57 · MichaelPaisner · Jan 24, 2023 · trineshsfdc · Apr 2, 2024
diff --git a/readme.md b/readme.md
diff --git a/Async_Request__c.object b/Async_Request__c.object
 Custom Object with the following fields:
 * Apex_Class_Name__c - Text(255)
 * Params__c - Long Text Area(131072)
 * Status__c - Picklist (New, 	Enqueued, Error)
 * Async_Apex_Job_Id__c - Text(18) (Unique Case Insensitive)	
 * Error_Message__c - Long Text Area(32768)
diff --git a/BaseQueueable.cls b/BaseQueueable.cls
 /**
 * @description Abstract class to be used for Queueable Jobs implementation. It removes completed Async_Request__c
 * records, populates detailed error message for failed jobs, and enqueues next pending Queueable jobs
 */
 public abstract with sharing class BaseQueueable implements Queueable {
    public void execute(QueueableContext context) {
        Savepoint savepoint = Database.setSavepoint();
        try {
            doExecute(context);

            delete [SELECT Id FROM Async_Request__c WHERE Async_Apex_Job_Id__c = :context.getJobId()];
        } catch (Exception ex) {
            Database.rollback(savepoint);

            Async_Request__c asyncRequest =
                [SELECT Id FROM Async_Request__c WHERE Async_Apex_Job_Id__c = :context.getJobId()];
            asyncRequest.Status__c = 'Error';
            asyncRequest.Error_Message__c =
                ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
                    + ex.getLineNumber() + '; stack trace: ' + ex.getStackTraceString();
            update asyncRequest;
        }

        QueueableManager.enqueueNextJob();
    }

    /**
     * @description This method should be overridden and implemented instead of execute() method of Queueable job.
     */
    public abstract void doExecute(QueueableContext context);
 }
diff --git a/QueueableManager.cls b/QueueableManager.cls
 /**
 * @description Utility class to enqueue Queueable Jobs. It is intended to be used as a replacement for
 * System.enqueJob() method. Advantages in comparison with the system method:
 * * Allows to enqueue Queueable job even if you have ran out of governon limit on number of Queueable jobs. It can
 *   be helpful in case you need to enqueue multiple Queueable jobs from Apex Batch Job, future method, or Queueable Job
 * * Better error handling. Error message contains full stack trace
 * 
 * The Queueable Job should support serialization to JSON string. JSON.serializePretty() and JSON.deserialize() are used
 * to serialize the job to Custom Field Params__c on  Async_Request__c
 * 
 * The Queueable Jobs should be derived from BaseQueueable abstract class. In case you need to enqueue some existing job,
 * you can create QueueableWrapper which is derived from BaseQueueable. It should take the Queueable job as a
 * constructor parameter.
 */
 public with sharing class QueueableManager {
    public static void enqueue(BaseQueueable queueable) {
        enqueue(new List<BaseQueueable>{queueable});
    }

    public static void enqueue(List<BaseQueueable> queueables) {
        List<Async_Request__c> asyncRequestsToInsert = new List<Async_Request__c>();
        Integer availableLimit = Limits.getLimitQueueableJobs() - Limits.getQueueableJobs();

        for (BaseQueueable queueable : queueables) {
            Async_Request__c asyncRequest = new Async_Request__c(
                Apex_Class_Name__c = getObjectType(queueable),
                Params__c = JSON.serializePretty(queueable)
            );
            if (availableLimit > 0) {
                asyncRequest.Async_Apex_Job_Id__c = System.enqueueJob(queueable);
                asyncRequest.Status__c = 'Enqueued';
                availableLimit--;
            } else {
                asyncRequest.Status__c = 'New';
            }
            asyncRequestsToInsert.add(asyncRequest);
        }
        insert asyncRequestsToInsert;
    }

    
    /**
     * @description Enqueues the next Queueable Job which is serialized to Async_Request__c object. It is
     * intended to be called from execute() method when logic of current Queueable Job is completed.
     */
    public static void enqueueNextJob() {
        if (
            Limits.getLimitQueueableJobs() == Limits.getQueueableJobs()
                || Limits.getLimitQueries() == Limits.getQueries()
                || Limits.getLimitQueryRows()  == Limits.getQueryRows()
                || Limits.getLimitDmlRows() <= Limits.getDmlRows() + 3
                || Limits.getLimitDmlStatements() <= Limits.getDmlStatements() + 3
                || Limits.getLimitCpuTime() <= Limits.getCpuTime() + 500
        ) {
            return;
        }

        Savepoint savepoint;
        try {
            Id currentUserId = UserInfo.getUserId();
            List<Async_Request__c> asyncRequests =
                [
                    SELECT Apex_Class_Name__c, Params__c
                    FROM Async_Request__c
                    WHERE Status__c = 'New' AND (CreatedById = :currentUserId OR LastModifiedById = :currentUserId)
                    LIMIT 1
                    FOR UPDATE
                ]
            ;

            if (asyncRequests.isEmpty()) {
                return;
            }

            Async_Request__c asyncRequest = asyncRequests[0];
            BaseQueueable queueable;
            try {
                queueable =
                    (BaseQueueable) JSON.deserialize(
                        asyncRequest.Params__c, Type.forName(asyncRequest.Apex_Class_Name__c)
                    )
                ;
            } catch (Exception ex) {
                asyncRequest.Status__c = 'Error';
                asyncRequest.Error_Message__c =
                    ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
                        + ex.getLineNumber() + '; stack trace: ' + ex.getStackTraceString()
                ;
                update asyncRequest;
                
                enqueueNextJob();
                return;
            }

            savepoint = Database.setSavepoint();
            Id jobId = System.enqueueJob(queueable);
            asyncRequest.Status__c = 'Enqueued';
            asyncRequest.Async_Apex_Job_Id__c = jobId;
            update asyncRequest;
        } catch(Exception ex) {
            if (savepoint != null) {
                Database.rollback(savepoint);
            }
            System.debug(
                ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
                    + ex.getLineNumber() + '; stack trace string: ' + ex.getStackTraceString()
            );
        }
    }

    /**
     * @description Workaround to get object type as a string dynamically
     * Source: https://salesforce.stackexchange.com/a/219558/47929
     */
    private static String getObjectType(Object obj) {
        String result = 'DateTime';
        try {
            DateTime typeCheck = (DateTime) obj;
        }
        catch(System.TypeException typeException) {
            String message = typeException.getMessage().substringAfter('Invalid conversion from runtime type ');
            result = message.substringBefore(' to Datetime');
        }

        return result;
    }
 }
	Custom Object with the following fields:
	* Apex_Class_Name__c - Text(255)
	* Params__c - Long Text Area(131072)
	* Status__c - Picklist (New, Enqueued, Error)
	* Async_Apex_Job_Id__c - Text(18) (Unique Case Insensitive)
	* Error_Message__c - Long Text Area(32768)
	/**
	* @description Abstract class to be used for Queueable Jobs implementation. It removes completed Async_Request__c
	* records, populates detailed error message for failed jobs, and enqueues next pending Queueable jobs
	*/
	public abstract with sharing class BaseQueueable implements Queueable {
	public void execute(QueueableContext context) {
	Savepoint savepoint = Database.setSavepoint();
	try {
	doExecute(context);

	delete [SELECT Id FROM Async_Request__c WHERE Async_Apex_Job_Id__c = :context.getJobId()];
	} catch (Exception ex) {
	Database.rollback(savepoint);

	Async_Request__c asyncRequest =
	[SELECT Id FROM Async_Request__c WHERE Async_Apex_Job_Id__c = :context.getJobId()];
	asyncRequest.Status__c = 'Error';
	asyncRequest.Error_Message__c =
	ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
	+ ex.getLineNumber() + '; stack trace: ' + ex.getStackTraceString();
	update asyncRequest;
	}

	QueueableManager.enqueueNextJob();
	}

	/**
	* @description This method should be overridden and implemented instead of execute() method of Queueable job.
	*/
	public abstract void doExecute(QueueableContext context);
	}
	/**
	* @description Utility class to enqueue Queueable Jobs. It is intended to be used as a replacement for
	* System.enqueJob() method. Advantages in comparison with the system method:
	* * Allows to enqueue Queueable job even if you have ran out of governon limit on number of Queueable jobs. It can
	* be helpful in case you need to enqueue multiple Queueable jobs from Apex Batch Job, future method, or Queueable Job
	* * Better error handling. Error message contains full stack trace
	*
	* The Queueable Job should support serialization to JSON string. JSON.serializePretty() and JSON.deserialize() are used
	* to serialize the job to Custom Field Params__c on Async_Request__c
	*
	* The Queueable Jobs should be derived from BaseQueueable abstract class. In case you need to enqueue some existing job,
	* you can create QueueableWrapper which is derived from BaseQueueable. It should take the Queueable job as a
	* constructor parameter.
	*/
	public with sharing class QueueableManager {
	public static void enqueue(BaseQueueable queueable) {
	enqueue(new List<BaseQueueable>{queueable});
	}

	public static void enqueue(List<BaseQueueable> queueables) {
	List<Async_Request__c> asyncRequestsToInsert = new List<Async_Request__c>();
	Integer availableLimit = Limits.getLimitQueueableJobs() - Limits.getQueueableJobs();

	for (BaseQueueable queueable : queueables) {
	Async_Request__c asyncRequest = new Async_Request__c(
	Apex_Class_Name__c = getObjectType(queueable),
	Params__c = JSON.serializePretty(queueable)
	);
	if (availableLimit > 0) {
	asyncRequest.Async_Apex_Job_Id__c = System.enqueueJob(queueable);
	asyncRequest.Status__c = 'Enqueued';
	availableLimit--;
	} else {
	asyncRequest.Status__c = 'New';
	}
	asyncRequestsToInsert.add(asyncRequest);
	}
	insert asyncRequestsToInsert;
	}


	/**
	* @description Enqueues the next Queueable Job which is serialized to Async_Request__c object. It is
	* intended to be called from execute() method when logic of current Queueable Job is completed.
	*/
	public static void enqueueNextJob() {
	if (
	Limits.getLimitQueueableJobs() == Limits.getQueueableJobs()
	\|\| Limits.getLimitQueries() == Limits.getQueries()
	\|\| Limits.getLimitQueryRows() == Limits.getQueryRows()
	\|\| Limits.getLimitDmlRows() <= Limits.getDmlRows() + 3
	\|\| Limits.getLimitDmlStatements() <= Limits.getDmlStatements() + 3
	\|\| Limits.getLimitCpuTime() <= Limits.getCpuTime() + 500
	) {
	return;
	}

	Savepoint savepoint;
	try {
	Id currentUserId = UserInfo.getUserId();
	List<Async_Request__c> asyncRequests =
	[
	SELECT Apex_Class_Name__c, Params__c
	FROM Async_Request__c
	WHERE Status__c = 'New' AND (CreatedById = :currentUserId OR LastModifiedById = :currentUserId)
	LIMIT 1
	FOR UPDATE
	]
	;

	if (asyncRequests.isEmpty()) {
	return;
	}

	Async_Request__c asyncRequest = asyncRequests[0];
	BaseQueueable queueable;
	try {
	queueable =
	(BaseQueueable) JSON.deserialize(
	asyncRequest.Params__c, Type.forName(asyncRequest.Apex_Class_Name__c)
	)
	;
	} catch (Exception ex) {
	asyncRequest.Status__c = 'Error';
	asyncRequest.Error_Message__c =
	ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
	+ ex.getLineNumber() + '; stack trace: ' + ex.getStackTraceString()
	;
	update asyncRequest;

	enqueueNextJob();
	return;
	}

	savepoint = Database.setSavepoint();
	Id jobId = System.enqueueJob(queueable);
	asyncRequest.Status__c = 'Enqueued';
	asyncRequest.Async_Apex_Job_Id__c = jobId;
	update asyncRequest;
	} catch(Exception ex) {
	if (savepoint != null) {
	Database.rollback(savepoint);
	}
	System.debug(
	ex.getTypeName() + ': ' + ex.getMessage() + '; cause: ' + ex.getCause() + '; line number: '
	+ ex.getLineNumber() + '; stack trace string: ' + ex.getStackTraceString()
	);
	}
	}

	/**
	* @description Workaround to get object type as a string dynamically
	* Source: https://salesforce.stackexchange.com/a/219558/47929
	*/
	private static String getObjectType(Object obj) {
	String result = 'DateTime';
	try {
	DateTime typeCheck = (DateTime) obj;
	}
	catch(System.TypeException typeException) {
	String message = typeException.getMessage().substringAfter('Invalid conversion from runtime type ');
	result = message.substringBefore(' to Datetime');
	}

	return result;
	}
	}