Tag Archives: Apex Trigger

Apex Trigger Context Variables

All triggers define implicit variables that allow developers to access runtime context.
These variables are contained in the System.Trigger class:

Variable Usage
isExecuting Returns true if the current context for the Apex
code is a trigger, not a Visualforce page,
a Web service, or an executeanonymous()
API
call.
isInsert Returns true if this trigger
was fired due to an insert operation, from the Salesforce user
interface, Apex,
or the API.
isUpdate Returns true if this trigger
was fired due to an update operation, from the Salesforce user
interface, Apex,
or the API.
isDelete Returns true if this trigger
was fired due to a delete operation, from the Salesforce user
interface, Apex,
or the API.
isBefore Returns true if this trigger
was fired before any record was saved.
isAfter Returns true if this trigger
was fired after all records were saved.
isUndelete Returns true if this trigger
was fired after a record is recovered from the Recycle Bin (that is, after an undelete operation from the Salesforce user
interface, Apex,
or the API.)
new Returns a list of the new versions of the sObject records. This
sObject list is only available in insert, update,
and undelete triggers, and the
records can only be modified in before triggers.
newMap A map of IDs to the new versions of the sObject records. This map
is only available in before
update
, after
insert
, after
update
, and after
undelete
triggers.
old Returns a list of the old versions of the sObject records. This
sObject list is only available in update and delete
triggers.
oldMap A map of IDs to the old versions of the sObject records. This map
is only available in update and
delete triggers.
size The total number of records in a trigger invocation, both old and
new.

Restrict multiple approval for a single user to a single record in Salesforce

I had a requirement to restrict multiple approval for a single user to a single record. There were multiple steps of approval process and the approver may be in different queue or as a manager for a user.

So, I implemented it using a trigger. In this article I’ll demonstrate how to implement it.
Here Application__c is the object, on which 3 steps approval process has implemented.
A custom check box field Check_Approver__c has set value to true, in all 3 steps field update action.

In below trigger I filtered the ProcessInstanceStep object records with current user Id in ActorId and the object Id (here object Id means record Id) in ProcessInstance.TargetObjectId.

  • If an User will approve or reject a record, then the SOQL query will return a single record.
  • If the SOQL query return a record, then trigger will throw an error message.

Trigger source code:

trigger ApplicationTrigger on Application__c (before Update)
{
    if(trigger.isUpdate){

        Id currentUserId = UserInfo.getUserId();
        for(Application__c sf: trigger.new){   
                  
            if(sf.Check_Approver__c == true){
              
                List<processinstancestep> existingApprovals = [SELECT ActorId
                                    FROM ProcessInstanceStep WHERE ProcessInstance.TargetObjectId = :sf.Id
                                    AND (StepStatus = 'Approved' OR StepStatus = 'Rejected')
                                    AND ActorId = :currentUserId];
                                      
                if(existingApprovals != null){
                  
                    if(existingApprovals.size() > 0){

                        sf.addError('You have already approved or rejeted the record.');
                    }
                }                  
             }
         }                         
    }
}