Wrapper Class in Apex/Visual force page

Wrapper class is a very powerful concept that can be used in multiple scenarios. Putting aside the word "Wrapper" it is nothing but just a class.Just like what we have in a class ,we  have methods,Properties etc in a wrapper class too.Here is an use case for wrapper class

Requirement : A Visual force page has to display all the Contacts available for an Account .Contacts should be listed out in the table row wise(default being column wise) . Only created "date"(Strip the time part) of the contact should be displayed .

Sample page:

Apex Code :

public class displayContacts<br /> { <br /> <br /> <br /> //Get the respective Account id<br /> ID accountId;<br /> <br /> //Store the wrapped Contacts<br /> public List<contactWrapper> conWrapper{get;set;}<br /> <br /> //COnstructor <br /> public displayContacts()<br /> { <br /> accountId= string.escapeSingleQuotes(ApexPages.currentPage().getParameters().get('id')); <br /> <br /> //Initialize list<br /> conWrapper = new List<contactWrapper>();<br /> for(Contact tempCon :[select FirstName,LastNAme,Email,phone,createddate from contact where accountid=:accountid])<br /> { <br /> //create the object for the wrapper class<br /> contactWrapper tempWrapper = new contactWrapper(tempCon);<br /> conwrapper.add(tempWrapper);<br /> }<br /> <br /> <br /> <br /> } //End of Constructor<br /> <br /> //Wrapper class for Contact<br /> public class contactWrapper<br /> { <br /> public String contactName{get;set;}<br /> public String createdDate{get;set;}<br /> public string phoneC{get;set;}<br /> public string emailC{get;set;}<br /> <br /> public contactWrapper(Contact con)<br /> {<br /> contactName=con.FirstName+' '+con.LastName;<br /> createdDate=con.createddate.month() +'/'+ con.createddate.day() +'/'+ con.createddate.year();<br /> phoneC=con.phone;<br /> emailC=con.email;<br /> <br /> }//End of Wrapper constructor<br /> <br /> }//End of wrapper class <br /> <br /> } //End of Class

Visual force page :
<br /> <apex:page controller="displayContacts"><br /> <apex:pageBlock><br /> <apex:pageBlockSection title="Contacts Available"><br /> <apex:dataTable value="{!conWrapper}" var="item1" border="1" columnsWidth="65px,100px" rowClasses="odd,even" styleClass="tableClass"><br /> <apex:column width="200px"><br /> <table width="250" border="0"> <tr><td><b>Name :</b></td><td>{!item1.contactName }</td></tr> <tr><td><b>Phone :</b></td><td>{!item1.phonec}</td></tr> <tr><td><b>Email :</b></td><td>{!item1.emailc} </td></tr> <tr><td><b>Created Date :</b></td><td>{!item1.createdDate} </td></tr> </table> </apex:column> <br /> </apex:dataTable><br /> </apex:pageBlockSection><br /> </apex:pageBlock><br /> </apex:page><br />

Result :

Huh!! now please don't catch a bug here that no values are displayed for phone. I admit i missed them..Pretty tired ...accept my apology and take it for granted :) :)

Power of wrapper is seamless .It can be used to process only the records that are selected in vf page.Click on the link for example.

http://wiki.developerforce.com/index.php/Wrapper_Class

Happy Coding!
C ya Soon with another Post

Relationship field not working in Trigger.New/Trigger.Old

While  i was working on a trigger i observed one strange behaviour. Lets say there is one custom object "Test__c" which has a look up to Account and the field being 'Account__c'. I performed update operation on Test__c so here is how my trigger would look like
<br /> if(Trigger.isupdate)<br /> {<br /> for(Test__c tempTest:Trigger.New)<br /> {<br />    String temp=tempTest.Account__r.Name;  //This dint work<br /> //Some code here<br />  }<br /> }<br />
Here though i was sure Name field of Account contains some value the same is not assigned to the string. I tried it many times but always ended up no where with no value being assigned.So instead of directly getting the value from Trigger.New i got the ids of "Test__c" records and then separately queried them to get respective values and to my surprise it worked..
<br /> <br /> if(Trigger.isupdate)<br /> {<br /> set<Id> testIds = new set<Ids>();<br /> for(Test__c tempTest:Trigger.New)<br /> {<br />    testIds.add(tempTest.id);<br /> //Some code here<br />  }<br /> }<br /> <br /> for(Test__c tempTest1 :[select Account__c,Account__r.Name from Test__c where id in :testIds])<br /> {<br />     String temp=tempTest1.Account__r.Name  //This worked<br /> }<br />

Though strange i dint understand the underlying concept (Totally Dark!!!) .Can some one beam some light on this !!


H C !! 

(Describe Information)How to retrieve all the fields in an Object

Recently i had a requirement of merging two accounts(Say one as "Parent" Account and other as "Child" Account).Following is one of the point listed out in requirement

If a parent Account field doesn’t contain a value and child Account contains that value, then the child Account field's value is populated in the parent field. ( On a lighter note ,how do people get these ideas  Note :This sentence is not a part of requirement though :) :) )

We have nearly 250+ fields(:O ..i dnt even remember 10% of those) in Account and according to the requirement almost all writable fields should be queried and checked for the blank/null value.

Requirement at
1) First we used the describe calls to get the list of fields available for the Object.
2) Looped through the fields available for the object and constructed the soql string for quering the records .
3) Returned the Parent record and child record based on the query constructed
4) Compared Parent and child account fields by using sobject method and updated accordingly


Please find the code snippet for this


<br /> Map <String, Schema.SObjectType> schemaMap = Schema.getGlobalDescribe();<br /> Map<String, Schema.SObjectField> fieldMap = schemaMap.get('Account').getDescribe().fields.getMap();<br /> <br /> //Declare a string to hold all the fields<br /> String fieldList; <br /> for(Schema.SObjectField sfield : fieldMap.Values()) <br /> { <br /> schema.describefieldresult dfield = sfield.getDescribe();<br /> String fieldName =dfield.getName();<br /> //Check the required conditions to include respecitve field into field list<br /> if(dfield.isAccessible()==true && dfield.isAutoNumber()==false && dfield.isCalculated()==false && dfield.isCreateable()==true && dfield.isUpdateable()==true)<br /> {<br /> if(fieldList==null)<br /> fieldList=fieldName;<br /> else<br /> fieldList=fieldList+','+fieldName; <br /> } <br /> }//End of For <br /> <br /> //Some arbitrary account ids<br /> ID parentAccountID='001A000000bGOvE';<br /> ID childAccountID='001A000000bGOvF';<br /> <br /> //Get the records<br /> Account parentAccount = Database.query('select '+fieldList+ ' from Account where id=:parentAccountID');<br /> Account childAccount = Database.query('select '+fieldList+ ' from Account where id=:childAccountID');<br /> <br /> List<string> getFieldList =fieldList.split(',');<br /> for(String getField :getFieldList)<br /> { <br /> system.debug('**********Field ID Retrieved'+getField);<br /> if(parentAccount.get(getField)==null && childAccount.get(getField)!=null)<br /> { <br /> parentAccount.put(getField,childAccount.get(getField));<br /> } <br /> }//End of for<br /> update parentAccount;<br /> <br />


Any better solution for this is highly appreciated :)

Date Time filter in Where Clause of Soql Query

"What if all our events in life are stored in database and we can query through the records to know about a specific day's events" -By UNKNOWN

 At times while checking for records in Force.com explorer(or any other tool like brain engine etc) we need to give some specific date time value(as filter) in the where clause of SOQL Query.


Apart from the date literals like Today,Yesterday etc we can give specific date time value. For Example 
26-April-2011 can be given as 2011-04-26T00:00:00Z


Including this in SOQL would look like:


select id,createddate from account where createddate= 2011-04-26T00:00:00Z


Following is the link where all date literals are listed out::
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_calls_soql_select_dateformats.htm




Happy Coding!! :)
Cheers

List Index Number

Definition of List from Answers.com :keep a record(This is the keyword here); tabulate
Antonyms: forget
Ok ok I understand..Here comes the main post :

Force.com developers use collection type "List" quite often .We use List when the sequence(Index) of elements is important.

Lets take an Example :Assume we have two lists List1 and List2

<br /> List<String> List1 = new List<String>();<br /> List<String>List2= new List<String>();<br /> //Lets add some string to these lists<br /> List1.add("FirstElement") ;// "FirstElement" is stored at Index no [0] in List1<br /> List2.add("FirstElement"); // "FirstElement" is stored at Indexno[0] in List2<br /> List2.add("SecondElement");//"SecondElement" is stored at Index no [1]in List1<br /> List1.add("SecondElement"); //"SecondElement" is stored at Index no [1] in List2<br />
As we added the Strings at the same time into two different lists we can be sure that respective strings have same Index no.

so  value at List1[i] = value at List2[i]  ..

Lets try to go through an USE CASE FOR THIS

Requirement  :Lets assume we have two objects Source(Custom Object) and  Contact(Standard Object) .Source object is a flat record (Normalized) object which stores contact Information and we need to push this data to Contact Object (De Normalizing)separately ie we need to insert two contacts as separate records.Also we need to track any error during insert operation at the source(custom object) level in a field called "Error Description" .( Note :For Simplicity only contact information is given)

Anatomy of Source Object:

Object Name :Source__c
Fields :
a) ContactName1__c
b) ErrorDescription__c
c)Email__c

Anatomy of Contact Object :
Object Name :Contact
Fields:
LastName
Email

Here in Contact Object Email is of Datatype "Email" .So proper email type value should be present in this field.

Following is the mapping: Assume we have two  records in the source object

In the above image we can observe that email mentioned for the second source record is not a valid one.So this would throw us an exception which is updated in the respective record's Error description field

Code for Insertion :

<br /> public class sourceToDestination<br /> <br /> {<br /> <br /> public sourceToDestination()<br /> <br /> { <br /> <br /> //List to Store Source Records for Error Tracking<br /> <br /> List<source__c> errorTrack = new List<source__c>();<br /> <br /> //List to Store the Contacts to be Inserted<br /> <br /> List<contact> contactInsert = new List<contact>();<br /> <br /> //Get the Source Records<br /> <br /> for(Source__c src :[select ContactName1__c,ContactName2__c,Email__c,ErrorDescription__c from source__c])<br /> <br /> { <br /> <br /> system.debug(src);<br /> <br /> //Create contact Object<br /> <br /> Contact contIns= new Contact();<br /> <br /> contIns.LastName=src.ContactName1__c;<br /> <br /> contIns.Email=src.Email__c;<br /> <br /> //Add the Contact to the List<br /> <br /> contactInsert.add(contIns); <br /> <br /> //Add the respective Source record to another List<br /> <br /> errorTrack.add(src);<br /> <br /> /*******As we added the elements of the List at the same time..Respective Index would be same */ <br /> <br /> } //End of For <br /> <br /> //Insert the Contact Records <br /> <br /> if(contactInsert.size()>0)<br /> <br /> { <br /> <br /> //Database method inserts the List without altering any index no<br /> <br /> Database.saveResult[] result = database.insert(contactInsert,false);<br /> <br /> //Initialize a temporay Integer<br /> <br /> Integer i=0; <br /> <br /> //Loop through the Contacts to know the status of insert operation<br /> <br /> for(Contact contTemp :contactInsert)<br /> <br /> { <br /> <br /> //Following returns the result for the Contact inserted based on index no<br /> <br /> Database.SaveResult sR=result[i];<br /> <br /> system.debug(contTemp);<br /> <br /> system.debug(sR);<br /> <br /> if(sR.issuccess())<br /> <br /> {<br /> <br /> //Do nothing<br /> <br /> }<br /> <br /> else<br /> <br /> {<br /> <br /> //Based on the Index No get the respective Source Record and <br /> <br /> //update the error description<br /> <br /> //getError is a method pertaining to saveREsult which returns <br /> <br /> //all the errors for the record<br /> <br /> errorTrack[i].ErrorDescription__c=String.valueof(sr.getErrors()[0]);<br /> <br /> } <br /> <br /> //Increment the integer <br /> <br /> i++;<br /> <br /> }//End of For <br /> <br /> }//End of If <br /> <br /> if(errorTrack.size()>0)<br /> <br /> update errorTrack; <br /> <br /> <br /> <br /> }//End of constructor <br /> <br /> <br /> <br /> }//End of Class<br />

I executed the code in the system log and following is the Status now:

In the image we can observe Error Description is updated with the respective error.

This would be very useful when we are loading data into different objects from a single object and need to track the errors at the source object level so that the data can be cleansed



Happy Coding :) !!

MAXIMUM DEBUG LOG SIZE REACHED

"I would love to lift the limits up, but salesforce won't give me the source code" :)


At times there could be a situation where Scripts statements are more and we hit the limit of "Debug Log Size" and we get the message "MAXIMUM DEBUG LOG SIZE REACHED" .One way to overcome this is to set filters for the debug logs as mentioned below :

Go to Monitoring-->DebugLogs-->Filters (set all the Filters to None expect for the apex Code)

In this way we restrict the log to show only the error part. But say u still want to get some other Information(Like HeapSize,State of different variables and statistics etc) from the Debug logs irrespective of the log filter.In such cases email messages help ...Just put the Email code at the Line  No where you want to track the code and then put the excepted results in the Subject or Text body of the email and send an Email to some one of your choice(probably in most cases the same person). So now the email tracks everything related to code :Here is an snippet of code which tries to get different values returned for limits .

I was working on batch apex and the size of debug log was tooooooo high...So to keep track of some governor limits and to know the status and state of different variables in the batch i used email concept.

Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();  
String[] toAddresses = new String[] {'chaitanya_cvm@yahoo.com'};         
mail.setToAddresses(toAddresses);                    
mail.setSubject('At Post Process limit queres::'+ limits.getScriptStatements ()+ 'No left::'+limits.getLimitScriptStatements () +'heapsize::'+limits.getHeapSize ()+'left'+limits.getLimitHeapSize());                   
mail.setPlainTextBody("Get Error Message:"+e.getmessage());                 Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });

            

So above mail just sends me the list of limits used and available limits etc



Note :Make sure to send emails to "Internal " users only so as to make sure we don't hit daily email limit. And most importantly remember to remove this code after unit testing is done :)

Happy Debugging!!!