fix(QueueableProcess): Updates Queueable Process (#345)

To Fix a logic, order-of-operations error, and to capture the results of the sub-class' execute method

Author: codefriar

force-app/main/default/classes/ULID/README.md

@@ -11,11 +11,11 @@
  */
 public with sharing class ULID {
 	/**
-	 * This character set is the complete list of allowed characters in
+	 * @description This character set is the complete list of allowed characters in
 	 * a ULID string. It intentionally does not include characters that
 	 * may be ambiguously read, such as i, l, o, and u characters.
 	 */
-	private static final List<String> CHARACTERSET = new List<String>{
+	private static final List<String> CHARACTER_SET = new List<String>{
 		'0',
 		'1',
 		'2',
@@ -50,23 +50,22 @@ public with sharing class ULID {
 		'Z'
 	};
 	// Calculate this once per transaction to avoid unnecessary math
-	private static final Long CHARACTERSETSIZE = CHARACTERSET.size();
-	// This is equal to 2^48-1 and represents the max timestamp
-	// allowed in a ULID string
+	private static final Long CHARACTER_SET_SIZE = CHARACTER_SET.size();
+	// This is equal to 2^48-1 and represents the max timestamp allowed in a ULID string
 	// private static final Long MAXTIME = 281474976710655L;
 	// This is the number of digits to encode the timestamp into.
-	private static final Long TIMELENGTH = 10;
+	private static final Long TIME_LENGTH = 10;
 	// This is the number of digits of random character to generate
-	private static final Integer RANDOMLENGTH = 16;
+	private static final Integer RANDOM_LENGTH = 16;
 
 	/**
 	 * @description Generates a ULID string according to spec.
 	 * https://github.com/ulid/spec
 	 * @return  `String`
 	 */
 	public static String generate() {
-		return encodeTimestamp(DateTime.now().getTime(), TIMELENGTH) +
-			generateRandomString(RANDOMLENGTH);
+		return encodeTimestamp(Datetime.now().getTime(), TIME_LENGTH) +
+			generateRandomString(RANDOM_LENGTH);
 	}
 
 	/**
@@ -76,13 +75,14 @@ public with sharing class ULID {
 	 * @param timeLength how many characters of the timestamp to encode
 	 * @return  `String`
 	 */
+	@SuppressWarnings('PMD.UnusedLocalVariable')
 	private static String encodeTimestamp(Long dtSeed, Long timeLength) {
 		Long modulo;
 		String retString = '';
 		for (Long l = timeLength; timeLength > 0; timeLength--) {
-			modulo = Math.mod(dtSeed, CHARACTERSETSIZE);
-			retString = CHARACTERSET[modulo.intValue()] + retString;
-			dtSeed = (dtSeed - modulo) / CHARACTERSETSIZE;
+			modulo = Math.mod(dtSeed, CHARACTER_SET_SIZE);
+			retString = CHARACTER_SET[modulo.intValue()] + retString;
+			dtSeed = (dtSeed - modulo) / CHARACTER_SET_SIZE;
 		}
 		return retString;
 	}
@@ -108,7 +108,7 @@ public with sharing class ULID {
 	 * @return  `String`
 	 */
 	private static String fetchRandomCharacterFromCharacterSet() {
-		Long rand = Math.mod(Math.abs(Crypto.getRandomLong()), CHARACTERSETSIZE);
-		return CHARACTERSET[rand.intValue()];
+		Long rand = Math.mod(Math.abs(Crypto.getRandomLong()), CHARACTER_SET_SIZE);
+		return CHARACTER_SET[rand.intValue()];
 	}
 }

force-app/main/default/classes/ULID/ULID.cls

@@ -162,7 +162,9 @@ private class PolyfillsTests {
 				(List<Contact>) SObjectFactory.createSObjects(
 					new Contact(AccountId = acct.Id),
 					5,
-					false
+					null,
+					false,
+					true
 				)
 			);
 		}

force-app/main/default/classes/polyfills/tests/PolyfillsTests.cls

@@ -68,11 +68,17 @@ public with sharing class EnqueueNextQueueableProcessStep implements System.Fina
 		switch on context.getResult() {
 			when SUCCESS {
 				if (this.processSteps.size() > 0) {
+					// Remove the first element from the list - this was constructed using the .then() method.
 					QueueableProcess nextProcessStep = this.processSteps.remove(0);
+					// Set the remaining steps on the next process step.
 					nextProcessStep.processSteps = this.processSteps;
+					// Set the dataPassthrough on the next process step.
 					nextProcessStep.dataPassthrough = dataPassthrough;
+					// Set the queueableContextHistory on the next process step.
 					nextProcessStep.queueableContextHistory = this.queueableContextHistory;
+					// Set the finalizerContextHistory on the next process step.
 					nextProcessStep.finalizerContextHistory = this.finalizerContextHistory;
+					// Enqueue the next process step.
 					System.enqueueJob(nextProcessStep);
 				}
 			}

force-app/main/default/classes/queueable process/EnqueueNextQueueableProcessStep.cls

@@ -61,9 +61,11 @@ public abstract class QueueableProcess implements Queueable, Database.AllowsCall
 
 	/**
 	 * @description This must be implemented by extending classes. Developers - implement this method with the work you
-	 * want executed asynchronously.
+	 * want executed asynchronously. The returned Object will be passed as dataPassthrough to the next step.
+	 *
+	 * @return Object - data to pass through to the next step in the process
 	 */
-	abstract public void execute();
+	abstract public Object execute();
 
 	/**
 	 * @description this is a default implementation of an handleError method. It's called by the finalizer if the
@@ -85,23 +87,23 @@ public abstract class QueueableProcess implements Queueable, Database.AllowsCall
 	 */
 	public virtual void execute(QueueableContext context) {
 		// if the queueableContextHistory is null, initialize it.
-		if (this.queueableContextHistory == null) {
-			this.queueableContextHistory = new List<QueueableContext>();
-		}
+		this.queueableContextHistory = this.queueableContextHistory ??
+			new List<QueueableContext>();
 		this.queueableContextHistory.add(context);
 
+		// Call the abstract method `execute` and capture its return value as the dataPassthrough for the next step.
+		Object nextDataPassthrough = execute();
+
 		// create a new instance of the finalizer class. Note that we're passing in the list of remaining steps and the
-		// passthrough data.
+		// returned data from execute() as the passthrough data for the next step.
 		Finalizer nextStep = new EnqueueNextQueueableProcessStep(
 			this.processSteps,
-			this.dataPassthrough,
+			nextDataPassthrough,
 			this.queueableContextHistory,
 			this.finalizerContextHistory
 		);
 		// Attach the finalizer to system context. This will take care of enqueueing the next QueueableProcess step in
 		// the nextStep.
 		System.attachFinalizer(nextStep);
-		// invoke the abstract method `execute`. see the comment above.
-		execute();
 	}
 }