5-ControlFlow.java

/* This Apex Class is a Unit Test Class and all the code can be checked by running the test.
* Copy this into a new Apex Class named "ControlFlow" and save it.
* As you read through it, look for "FIX ME!" and make the changes suggested.
* If your changes are correct all the tests (System Asserts) will pass.
* 
* You can also see what's happening in the Logs by opening a Log and checking the Debug Only box
* you can compare the line numbers in the Log to the line number in the Class to find a specific
* debug entry.
*/

@isTest
public class ControlFlow {
    static testMethod void logic(){
      
        //IF statements. These are just like Workflow Rules.
        if(true){
            //And here is your Workflow Action in between the curly brackets
            System.debug('Do Something!');
        }
        
        //you can condense it to one line if there's only one action.
        if(true) System.debug('Still do something');
        
        //prep a true/false variable for the next step.
        Boolean myBool = true;
        
        //use "else" when you only want the action to happen when your if case is false
        //This is what Workflow Rules can't do: actions for multiple results from one rule
        if(myBool){
            System.debug('The Boolean was true');//only runs if myBool is true
        } else {
            System.debug('The Boolean was false');//only runs if myBool is false
        }
        System.debug('The Boolean doesn\'t matter here');//This line will always run
        
        //you can string multiple condition cases with "else if"
        if(myBool){
            System.debug('The Boolean was: ' + myBool);
        } else if(!myBool){
            System.debug('The Boolean was: ' + myBool);
        } else {
            System.debug('Whoa! there was no value');
        }
        
        //FIX ME!: Try changing myBool to false and confirm that the conditions cascade to the next condition
        //FIX ME!: Try not setting myBool to any value and see what happens...
        
        //And just so you know it exists, there is the ternary operator for if-else statements
        //This has to be used with variable assignment, so its use is limited but elegant
        //Here, we set a String of "true" or "false" depending on the Boolean value
        String theAnswer = (myBool ? 'true' : 'false');
        
        //FIX ME!: Google "Apex Boolean Methods" to find how to convert the String named theAnswer to a Boolean
        //and then assert that myBool equals theAnswer.
        //Hint: Since we cannot directly compare a String to a Boolean, you have to create a new Boolean "b" with the conversion.
        //Boolean b = ???;
        //System.assertEquals();        
        
        //Most of the time we're comparing two things in our conditions
        //You have to get used to typing "==" when you think "equals" in conditions
        if(theAnswer.length() == 4){
            System.debug('exactly 4 characters long');
        } else if(theAnswer.length() >= 5){
            System.debug('longer than 5 characters');
        }
        
        //FIX ME!: Now that you know about using "==" to compare values, 
        //rewrite this conditional block to handle different string values as well as null values.
         String myPicklist = 'up';
        /*
        if(myPicklist){
        System.debug('The value is up');
        System.assertEquals('up',);
        } else if(myPicklist){
        System.debug('The value is down');
        System.assertEquals('down',);
        } else if(myPicklist){
        System.debug('The picklist was empty');
        System.assert(,);//Can you find an Apex String method to test if a string is null?
        } else {
        System.debug('The value was neither up nor down nor null');//what do you have to set myPicklist to to get this result?
        System.assert? //How would you test that the string is not 'up', 'down' or null?
        }
		*/
        
        //Any method that returns a boolean can be used in the condition clause.
        //With Maps, a common pattern is to check for a value's existence before getting the value,
        //and if it's not there, put it in the Map.        
        //prep a Map first so we have something to work with.
        Map<String, Decimal> metricMap = new Map<String, Decimal>{'Kilo' => 1000, 'Milli' => .001};
      
        if(metricMap.containsKey('Mega')){
            System.debug('Mega is already there!');
            System.debug(metricMap.get('Mega'));
        } else {
            metricMap.put('Mega', 1000000);
        }
        System.assertEquals(metricMap.get('Mega'), 1000000);
        
        //FIX ME!: Add "Micro" to the metricMap so the following System Assert passes
        if(metricMap.containsKey('Micro')){
            //System.debug('Micro is already there!');
        } else {
            //metricMap.put('', .000001);
        }
        //System.assertEquals(,metricMap.get(''));
        
        //let's prep some Booleans to play with comparison operators
        Boolean x = true;
        Boolean y = false;
        
        //Conditionals can contain chains of variables (or boolean methods).
        //Comparison operators follow the rules of logic you use everyday in Reports, Views and Formulas
        if(x && y) System.debug('True AND False evaluates to False');
        if(x && !y) System.debug('True AND NOT False evaluates to True');
        if(x || y) System.debug('True OR False evaluates to True');
        if(!x || y) System.debug('Not True OR False evaluates to False');
        if(!(x && y)) System.debug('True AND False evaluates to False, BUT we re-evaluate that cumulative False to True with NOT(!)');
        
        //FIX ME! Add in a third Boolean "z" to get these conditions to be true
        Boolean z = true;
        //if(x && y) System.debug('Now it evaluates to True!');
        //if(!x || y) System.debug('Now it evaluates to True!');
        
        
        
        ////////////////
        // FOR LOOPS  //
        ////////////////
        
        //For Loops allow you to work with multiple variables or objects
        //There wasn't a good equivalent in the UI until Process Builder came along
        //In Apex, they are an essential control for, well, everything!
        
        //First variation: For each item in a List or Set, do something
        Set<String> metricSet = metricMap.keySet();//Remember these are: ['Mega', 'Micro', 'Milli']
        
        for(String s : metricSet){//for every string in metricSet do something...
            System.debug(s);
        }
        
        //FIX ME! Now that we've looped through the keys in metricSet, loop through the values
        List<Decimal> metricValues = metricMap.values();
        //for(){
            //system.debug();
        //}
        
        //Second variation: for each record returned by a SOQL query, do something.
        for(User u : [Select Name from User]){
            System.debug(u.Name);
        }
        
        //FIX ME! Write a for loop that retreive all the Profile Names and prints them in a System Debug
        //Note that in Unit Tests without SeeAllData = True, Users and Profiles are still accessible along with a few other special Objects
        
        //for(Profile p : []){
        	//System.debug();
        //}
        
        
        //Third variation: repeat the loop as many times as instructed
        //This uses a special format common to many languages of establishing:
        //1. An Entry Condition: Integer i = 0 (arbitrary, but 0 is useful when working with list indices)
        //2. A Comparison: i < 5 (means "as long as")
        //3. An Incrementor: i++ (add 1 to i each loop)
        for(Integer i = 0 ; i < 5 ; i++){
            System.debug('i now equals: ' + i);
        }
        
        List<String> names = new List<String>{'Kahlil', 'Daniela', 'Mohamed', 'Liu'};
            String d = names[0];
        
        //A very frequent pattern is repeating the loop for each item in a list using the list.size() method
        for(Integer i = 0; i < names.size(); i++){
            System.debug('Value at index ' + i + ' is ' + names[i]);//we can use i to retrieve each item in the list in order
        }
        
        //FIX ME! Make a for loop of 5 Integers that adds each Integer to itself
        //use a system debug to output the result like "1 + 1 = 2"
        //you have to use 3 variations on + to do this: 
        //1. + to concatentate two items
        //2. + as a string to print out the plus sign (and later the equals sign)
        //3. + as a mathematical operator to add the two Integers
        //for(){
            //System.debug();
        //}
        

            
        //Loop-di-Loop. You can embed loop within loops.
        
        //prep some units of measurement
        List<String> units = new List<String>{'meter', 'watt', 'gram'};
        //The first iteration will loop through all the values in the inner loop first
        //and then proceed on to the next item in the outer loop
        for(String u : units){
            for(String m : metricMap.keySet()){
               System.debug('A ' + m + u + ' is ' + metricMap.get(m) + u + 's');//We use m to get the string and the metric multiplier from the Map!
            }
        }
        
        //FIX ME! BIG CHALLENGE!!!
        //Let's revise the FIX ME challenge from our SOQL lesson to use loops
        //1. Create a Query to get all Contacts that are missing both a phone number and email address

        //2. Create an empty collection to hold records we want to update

        //3. Set the Contacts' Phone Number to the Account's Phone Number

        //4. Put the records into your update collection

        //5. Now, since we don't know the email, let's set CleanStatus to 'Skipped'

        //6. Put the records into your update collection

        //7. Use an "update" call to save the changes and commit them to the database

        //8. Write a Unit Test to confirm it worked!
    }
}