Add methods to retrieve specific records

sfdx-source/apex-common/main/classes/fflib_SObjects.cls

@@ -54,6 +54,61 @@ public virtual class fflib_SObjects
 		SObjectDescribe = sObjectType.getDescribe();
 	}
 
+	/**
+	 * @param id Domain containing primary key (Id field) values
+	 *
+	 * @return Returns only the SObjects from the domain matching the given Ids.
+	 */
+	public virtual SObject getRecord(Id id)
+	{
+		List<SObject> result = getRecords(new Set<Id> {id});
+
+		return (result.size() == 0) ? null : result.get(0);
+	}
+
+	/**
+	 * @return Returns the contents of the Domain by their primary Key ('Id' field)
+	 */
+	public virtual Map<Id, SObject> getRecordsById()
+	{
+		return new Map<Id, SObject>(getRecords());
+	}
+
+	/**
+	 * @param ids A Set containing primary key (Id field) values
+	 *
+	 * @return Returns only the SObjects from the domain matching the given Ids.
+	 */
+	public virtual List<SObject> getRecords(Set<Id> ids)
+	{
+		Map<Id, SObject> sObjectsByIds = getRecordsById();
+		List<SObject> result = new List<SObject>();
+		for (Id id : ids)
+		{
+			if (sObjectsByIds.containsKey(id) == false) continue;
+
+			result.add(sObjectsByIds.get(id));
+		}
+		return result;
+	}
+
+	/**
+	 * @param ids A Set containing primary key (Id field) values
+	 *
+	 * @return Returns the SObjects from the domain which are not part of the given Ids.
+	 */
+	public virtual List<SObject> getRecordsNotIn(Set<Id> ids)
+	{
+		List<SObject> result = new List<SObject>();
+		for (SObject record : getRecords())
+		{
+			if (ids.contains(record.Id)) continue;
+
+			result.add(record);
+		}
+		return result;
+	}
+
 	public virtual List<SObject> getRecords()
 	{
 		return (List<SObject>) getObjects();

sfdx-source/apex-common/test/classes/fflib_SObjectsTest.cls

@@ -45,6 +45,38 @@ private class fflib_SObjectsTest
 		);
 	}
 
+	@IsTest
+	static void itShouldReturnRecordsByIds()
+	{
+		final Id accountIdA = fflib_IDGenerator.generate(Schema.Account.SObjectType);
+		final Id accountIdB = fflib_IDGenerator.generate(Schema.Account.SObjectType);
+		final Id accountIdC = fflib_IDGenerator.generate(Schema.Account.SObjectType);
+
+		fflib_SObjects domain = new fflib_SObjects(
+				new List<SObject>
+				{
+						new Account(Id = accountIdA, Name = 'A'),
+						new Account(Id = accountIdB, Name = 'B'),
+						new Account(Id = accountIdC, Name = 'C')
+				});
+
+		Set<Id> idsToRetrieve = new Set<Id> {accountIdA, accountIdC};
+
+		// Get just a subset of the domain
+		List<SObject> subSetRecords = domain.getRecords(idsToRetrieve);
+		Set<Id> resultIds = new Map<Id, SObject>(subSetRecords).keySet();
+		System.assertEquals(2, subSetRecords.size(), 'Unexpected amount of record returned');
+		System.assert(resultIds.containsAll(idsToRetrieve), 'Did not retrieve the correct records');
+
+		// Get all the other records
+		List<SObject> allOtherRecords = domain.getRecordsNotIn(idsToRetrieve);
+		System.assertEquals(1, allOtherRecords.size(), 'Unexpected amount of record returned');
+		System.assertEquals(accountIdB, allOtherRecords.get(0).Id, 'Did not retrieve the correct record');
+
+		// Get a single specific record
+		System.assertEquals(accountIdB, domain.getRecord(accountIdB).Id, 'Incorrect record retrieved from domain');
+	}
+
 	@IsTest
 	static void itShouldReturnRecordsWithFieldValues()
 	{