SFDC Advanced Apex

Force.com Apex Advanced
Sujit Kumar
Zenolocity LLC © 2012 - 2024

Overview
• Aggregate SOQL Features
• Additional SOQL Features
• SOSL
• Transaction Processing
• Managed Sharing
• Send & Receive Email
• Dynamic Apex
• Patterns and Matchers
• Custom Settings in Apex
• System class and methods

Aggregate Functions
• AVG, COUNT, COUNT_DISTINCT, MIN, MAX,
SUM.
• AVG, SUM : Operate on Numeric Fields only.
• COUNT, COUNT_DISTINCT, MIN, MAX:
Numeric, Date, String fields.
• All queries containing aggregate functions
return a special Apex object called
AggregateResult, except the no-argument
form of COUNT, which returns an integer.

Examples
• Returns Integer or AggregateResult object.
• Default field names expr0 for the first field, expr1
for 2nd field, and so on.
Integer i = [ SELECT COUNT() FROM Timecard__c ];
System.debug(i);
AggregateResult r = [ SELECT
SUM(Total_Hours__c) Total
FROM Timecard__c ];
System.debug(r.get('Total'));

Grouping Records With Subtotals
• Two forms of grouping produce subtotals and
grand totals for the record groupings specified
in the query.
• GROUP BY ROLLUP
• GROUP BY CUBE: causes all possible
combinations of grouped fields to receive
subtotals.
• These replace the GROUP BY syntax and
support up to 3 grouped fields.

Example of Group By ROLLUP
for (AggregateResult r : [ SELECT Project__r.Status__c,
Resource__r.Region__c,
SUM(Total_Hours__c) hours, COUNT(Id) recs,
GROUPING(Project__r.Status__c) status,
GROUPING(Resource__r.Region__c) region
FROM Timecard__c
GROUP BY ROLLUP(Project__r.Status__c, Resource__r.Region__c)
ORDER BY GROUPING(Project__r.Status__c),
GROUPING(Resource__r.Region__c) ])
{
System.debug(LoggingLevel.INFO,
r.get('Status__c') + ' ' + r.get('Region__c') + ' ' +
r.get('region') + ' ' + r.get('status') + ' ' +
r.get('hours') + ' ' + r.get('recs'));
}

SOQL Outer and Inner Joins
• A SOQL statement consists of a single base object,
specified using the FROM keyword.
• All fields in the base object can be retrieved in the
query, as well as fields from parent and child objects
depending on their distance away from the base
object.
• Force.com takes care of joining related objects
together to retrieve the requested fields.
• These implicit joins are always outer joins. An outer
join returns all records from the base object, including
records that do not refer to a related object.
• Adding a where clause makes it an Inner Join.

Examples
• SOQL Outer Join
SELECT Name, Account__r.Name
FROM Proj__c
• SOQL Inner Join
SELECT Name, Account__r.Name
FROM Proj__c
WHERE Account__c != null

SOQL Semi-Join
• Allow records from one object to be filtered
by a subquery against another object.
• Example of parent-to-child semi-join
SELECT Id, Name
FROM Account
WHERE Id IN
(SELECT Account__c FROM Proj__c
WHERE Status__c = 'Yellow')

SOQL with child-to-child Semi-Join
• Example below selects the records in the
Timecard object that are filtered by resources
which have at least one assignment as a
consultant.
SELECT Project__r.Name, Week_Ending__c,
Total_Hours__c
FROM Timecard__c
WHERE Resource__c IN
(SELECT Resource__c FROM Assignment__c
WHERE Role__c = 'Consultant')

SOQL with child-to-parent Semi-Join
• Timecards are filtered to include resources with an hourly
cost rate of more than $100. Child-to-parent refers to the
relationship between the Timecard and Resource objects.
• Resource is the parent object, and it is being used to
restrict the output of the query on Timecard, the child
object.
SELECT Project__r.Name, Week_Ending__c, Total_Hours__c
FROM Timecard__c
WHERE Resource__c IN
(SELECT Id FROM Resource__c
WHERE Hourly_Cost_Rate__c > 100)

SOQL Anti-Join
• An anti-join is the negative version of a semi-join.
It uses the NOT IN keyword to allow the subquery
to exclude records.
• Example: Query below returns all Accounts
except those containing Projects in a green
status.
SELECT Id, Name
FROM Account
WHERE Id NOT IN
(SELECT Account__c FROM Proj__c
WHERE Status__c = 'Green')

Restrictions: Semi-Joins and Anti-Joins
• The selected column in the subquery must be a
primary or foreign key and cannot traverse
relationships. It must be a direct field on the child
object.
• A single query can include at most two semi-joins or
anti-joins.
• SJs and AJs cannot be nested within other SJ and AJ
statements and are not allowed in subqueries.
• The parent object cannot be the same type as the
child.
• Subqueries cannot be nested and cannot contain the
OR, count(), ORDER BY, or LIMIT keywords

Semicolon (AND), INCLUDES and
EXCLUDES for Multi-Select Picklists
• Query below returns Project records with the
multiple selection of Apex, Java, and C# in the
Requested Skills field and also records with
only Python selected.
SELECT Id, Name
FROM Proj__c
WHERE Requested_Skills__c INCLUDES
('Apex;Java;C#', 'Python')

SOSL Overview
• SOSL query specifies search terms and scope.
• The search terms are a list of string literals and
can include wildcards.
• The search scope is fields containing string
data from one or more objects. This excludes
Number, Date, and Checkbox fields from being
searched with SOSL.

SOSL Details
• Syntax: FIND ’query’ IN search group RETURNING field
specification LIMIT record limit
• Apostrophes around query are required.
• Limited to 20 SOSL queries returning a maximum of
200 rows per query.
• Query: one or more words or phrases to search on.
Can use * or ?. Enclose a search term in quotation
marks to perform an exact match on multiple words.
Use the logical operators AND, OR, and AND NOT to
combine search terms and parentheses to control the
order in which they’re evaluated. Searches are case-insensitive.

SOSL Details (contd…)
• Search Group: indicates types of fields to search in each
object. Valid values are ALL FIELDS (all string fields), NAME
FIELDS, EMAIL FIELDS, PHONE FIELDS. Default is ALL FIELDS.
• Field Specification: comma separated list of objects to
include in the search results. Optionally, you can specify
additional fields to return by enclosing them in
parentheses. You can also specify conditional filters using
the same syntax as the SOQL WHERE clause, set the sort
order with the ORDER BY keyword, and use the LIMIT
keyword to limit the number of records returned per
object.
• Record Limit: Optional, defaults to 200.

SOSL in Apex
List<List<SObject>> result = [
FIND 'Chicago'
RETURNING Proj__c(Name), Resource__c(Name)
];
List<Proj__c> projects = (List<Proj__c>)result[0];
for (Proj__c project : projects) {
System.debug('Project: ' + project.Name);
}
List<Resource__c> resources = (List<Resource__c>)result[1];
for (Resource__c resource : resources) {
System.debug('Resource: ' + resource.Name);
}

Transaction Processing
• Database DML Methods – Add support for
partial success of a batch.
• Savepoint - Returning to a savepoint rolls back
all DML statements executed since the
creation of the savepoint.
• Record Locking – provides exclusive write to
update.

Implicit Transactions in Apex
• All database operations in Apex are transactional.
• Every trigger runs in a transaction. If there is an
uncaught exception in a trigger, all DML
operations are rolled back.
• If multiple triggers fire for a single database
operation, all triggers succeed or fail as a group.
• DML statements accept a single record or batch
of records. When operating on a batch, they
succeed or fail on the entire group of records.

DML Database Methods
• Allow batch DML operations to fail on
individual records without impacting the
entire batch. To do this, they do not throw
exceptions to indicate error.
• Instead they return an array of result objects,
one per input record. These result objects
contain a flag indicating success or failure, and
error details in the event of failure.

Database DML Methods
• A DML database method exists for each of the
DML statements – insert, update, upsert, delete.
• Each method takes an optional Boolean
parameter called opt_allOrNone to specify batch
behavior. The default value is true, indicating that
the behavior is “all or none.”
• This makes the method identical to a DML
statement, with one failed record causing the
failure of all records and a DmlException.
• But if the opt_allOrNone parameter is false,
partial success is allowed.

Database Savepoint Usage
void printRecordCount() {
System.debug([ SELECT COUNT() FROM Resource__c ] + ' records');
}
printRecordCount();
Savepoint sp = Database.setSavepoint();
delete [ SELECT Id FROM Resource__c ];
printRecordCount();
Database.rollback(sp);
printRecordCount();

Record Locking
• Write locks on records.
• Use the keyword “for update”.
• Prevents dirty writes.
• You cannot use the ORDER BY keyword with FOR
UPDATE. Query results are automatically ordered
by Id field.
Resource__c tim = [ SELECT Id, Hourly_Cost_Rate__c
FROM Resource__c
WHERE Name = 'Tim Barr' LIMIT 1
FOR UPDATE ];
tim.Hourly_Cost_Rate__c += 20;
update tim;

DML Statement Guidelines
• Max of 200 sObject records in a single method.
• Operate on only 1 type of sObject at a time.
• Non-null value for all required fields.
• Id for current sObject record cannot be modified
but related IDs can.
• Upsert can contain 2 separate calls, update &
insert.
• Merging works for only 3 records at a time.
• Merging is Only for Leads, Contacts and Accounts.
• Commit is implicit, Rollback is explicit.

Database.DMLOptions object
• Lets you add extra info during a transaction
like:
Truncation behavior
Trigger assignment rules.
Trigger email notification based on certain events.

Emails – Sending
• SingleEmailMessage : up to 10 receivers.
• SingleEmailMessage With Template : unique IDs
of Contact or Lead objects must be used instead
of strings to provide the receivers’ email
addresses. Cannot be used to for internal user
email addresses. Substitute fields from receiver’s
record or optional related object. Up to 10
receivers. Email Templates can be created from
VF pages.
• MassEmailMessage : up to 250 receivers.

Messaging.sendEmail Method
• Transactional - just like DML methods.
• Can send single email or mass emails.
• Plain text or Html formats supported.
• Governor Limits – total 10 invocations per
context.
• Single or Mass emails sent from Apex count
against the daily mass limit.
MASS_MAIL_LIMIT_EXCEEDED error code if
limit exceeded.

Limits
• Max of 1000 emails to external email
addresses. No limit for internal email
addresses.
• Number of external email addresses varies by
edition (250-Prof, 500-Ent, 1000-unlimited).

Apex Email Services
• Inbound Email Integration.
• Classes part of the Messaging namespace.
• Total messages processed per day = Number
of user licenses x 1000.
• Email service addresses from sandbox cannot
be copied to prod org.
• Can restrict the domains from which we can
receive emails.

Inbound Email Objects
• Write an Apex class that implements a specific interface
(Messaging.InboundEmailHandler) and method
(handleInboundEmail).
• Provides your code access to the
envelope: InboundEnvelope and
content: InboundEmail of inbound emails, including body, subject,
fromAddress, toAddress, binaryAttachments, textAttachments.
• The return value of this method is an InboundEmailResult object.
• To indicate processing failure, set the success field of this object to
false. Any explanatory message set in the message field is returned
to the sender as an email response.

Inbound Email Processing
• Create an Email Service using the native user
interface – service name, apex class, accept
attachments setting, sending server
authentication protocols, etc.
• An Email Service is associated with one or
more Force.com-issued email addresses that
serve as the gateways to the Apex class.
• When email arrives at the email address, your
Apex class is invoked to process it.

Inbound Email Processing
• No access to system log in the context of an
inbound email handler class. Create custom
objects to log any exceptions or debug
statements.
• Request set of incoming emails from the UI
within a certain date range. Notification sent
when request is processed.
• Processing of emails by the email service
handler can be seen in the Debug logs.

Other Features
• Apex managed sharing: Rules governing record sharing
can be controlled in Apex code.
• Dynamic Apex: Although Apex features strongly typed
database objects and queries, you can also write code that
uses database resources dynamically. This carries with it
the risk of runtime errors but opens up new possibilities of
dynamic behavior to your applications. The SObject is a
typeless database object. It allows you to interact with
database records without declaring them as a specific type.
• Custom Settings in Apex: You can read and write custom
settings from Apex like any database object, but without
the governor limits.

Dynamic Apex
• Dynamic Apex - no hardcoding of names of fields and objects.
Schema Describe - similar to metadata API.
• Dynamic SOQL - no hardcoding of query.
• Dynamic SOSL
• Dynamic DML - create sObject dynamically using newSObject
method on an SObjectType token. Then insert that new object into
the database.
Example:
Account A = new Account();
Schema.sObjectType tokenA = A.getSObjectType();
Account B = (Account) tokenA.newSObject();

Patterns and Matchers
• Similar to Java.
• Reuse requires compilation of the pattern.
Pattern myPat = Pattern.compile('a*b');
Matcher myMatcher = myPat.matcher('aaaab');
myMatcher.matches();
• Single Invocation:
Pattern.matches('a*b', 'aaaaab');

System Class
• abortJob
• assert, assertEquals, assertNotEquals
• currentPageReference
• Debug
Set the logging level:
System.debug (Logginglevel.ERROR);
• getApplicationReadWrite (returns the read write mode set for an
org during SF.com upgrades and downtimes)
• isBatch, isFuture, isScheduled
• now (datetime as GMT), today (date in user’s tz)
• runAs
• schedule
• submit

System.schedule(…)
• After you implement a class with
the Schedulable interface, use
the System.Schedule method to execute it.
• The scheduler runs as system: all classes are
executed, whether the user has permission to
execute the class or not.
• Example:
proschedule p = new proschedule();
// secs mts HH24 day mon day_of_week optional_yr
String sch = '0 0 8 13 2 ?';
System.schedule('One Time Pro', sch, p);

Library Classes
• UserInfo - most methods are getter methods like
getUserId(), getUserName(),
getOrgId(), getOrgName()
getDefaultCurrency()
getLocale()
getSessionID()
• Math - abs(), min(...), rand() returns double between 0.0 and 1.0
• clone() method returns a shallow copy of any SO or CO.
• Limits class returns the values of governor limits.
• Two versions for each method.
Examples:
Limits.getDMLRows() – amount used in the current context
Limits.getLimitDMLRows() - amount available in the current context
• Useful to print using System.debug() for debugging purpose.

SFDC Advanced Apex

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