How to Call Method in Another Method Within One Class?

Question

I have three custom objects named Parent__c, Child__c, and A__c. I've used A__c as the standardcontroller. It serves as the search page for Parent__c record, wherein on click of a lookup field, all Parent__c info, including Child__c records for that specific searched parent record, will be displayed automatically.

The current state of the controller queries Parent__c and Child__c in different methods within that class alone. One apex method is for getting all the Parent__c records, while the other method focuses on getting all the Child__c records related to that parent record.

How can I call method inside another method within just a single apex class? Meaning call the Child__c method inside the Parent__c method.

method1:for parent method

//some code....assume we already declared some variables
public void search() {
    parentqry = [SELECT Id, Name FROM Parent__c WHERE Id =: A__c.Parent__c];
} 

method2:for child method

//some code...this gets the `Child__c` records associated with the searched Parent__c record. let's assume we already have a wrapper class named `WrapperClass`....
public List<WrapperClass> getChild() {
    if(childList == null) {
        childList = new List<WrapperClass>();
        for(Child__c c :[SELECT Id, Name, Parent__c, Type__c FROM Child__c WHERE Parent__c =: A__c.Parent__c]) {
        }
    } 
} 

Answer 1

If you want to get all the children for this parent record, why don't you bring it together into one single SOQL query in search()?

parentqry = 
  [SELECT Id, Name, 
    (SELECT Id, Name, Parent__c, Type__c FROM Child__r) FROM Parent__c
  WHERE Id =: A__c.Parent__c];

Answer 2

You can call the other method in the One Method by following:

public void search() {
    parentqry = [SELECT Id, Name FROM Parent__c WHERE Id =: A__c.Parent__c];
    List<WrapperClass> childListYoWant = getChild();
} 

public List<WrapperClass> getChild() {
    if(childList == null) {
        childList = new List<WrapperClass>();
        for(Child__c c :[SELECT Id, Name, Parent__c, Type__c FROM Child__c WHERE Parent__c =: A__c.Parent__c]) {
        }
    }
    return childList;
} 

Hope this will help.