Thursday, April 30, 2015

A Web Service CallOut Per Minute In Between Business Hours

There was a very specific requirement from customer, as per the requirement he wanted to call a external websrvice in every minute during the business hours. I tried several ways to do it but that was really not simple. Even I was not sure it can hit any governor limit. I did google a lot for this but there was no help in case of per minute. Finally started to get if there is any solution in salesforce for this, without having confidence is this really possible in salesforce. But finally I got the solution & the best thing is it works without hitting any kind of governor limits. Here is the solution which can help if you stuck this kind of requirement.

#1-Create a new object called “Scheduled_Job__c”. This object will have below fields –
Request_DateTime__c – Type DateTime
Response__c – Type Long Text Area(32768)

This object will be used in two ways latter-
#A-track the request time &
#B-What is the response from the external web service.
#2-I created a batch class which allows callouts.
global class ScheduleLeads implements Schedulable,Database.AllowsCallouts {
 global void execute(SchedulableContext ctx) { 
      init(); 
 }
}

#3-Created a method in this class called ScheduleJob which will basically can be called from execute anonymous to schedule this job.
public static void ScheduleJob(){
 boolean isNeedToSchedule = true;
 String strSchedule = '';
/*here notice that we are adding a minute in current time, means it will be scheduled for next minute, you can change it even if you want to call every n minutes*/
 DateTime dt = Datetime.now().addMinutes(1);
/*Let’s say business hours is from 10 AM to 8 PM*/
 if(dt.hour() >=19 && dt.minute() >= 59){ 
         isNeedToSchedule = false;
 }else{
     strSchedule = '0 ' + dt.minute() + ' ' + dt.hour() + ' ' + dt.day() + ' ' + dt.month() + ' ?' + ' ' + dt.year(); 
     isNeedToSchedule = true;
 }
 if(isNeedToSchedule){
   String cronid = System.schedule('CalloutService_' + Datetime.now().getTime(), strSchedule, new ScheduleVWLeads());
  
   List listOfScheduledJob = [Select Id,Response__c from Scheduled_Job__c Order by CreatedDate DESC LIMIT 1];
   if(listOfScheduledJob != NULL && !listOfScheduledJob.isEmpty()){
    /*try{ 
     delete listOfScheduledJob;
    }catch(Exception ex){
     system.debug('exqqq::--->>>>' + ex);
    }*/
   }
   Scheduled_Job__c objScheduledJob = new Scheduled_Job__c();
   objScheduledJob.Name = cronid;
   objScheduledJob.Request_DateTime__c = datetime.now();
   insert objScheduledJob;
 }      
}

#4-Create another method called init
@future(callout=true)
  public static void init(){
     HttpRequest req = new HttpRequest();
  Http http = new Http(); 
  req.setMethod('GET');
  String requrl = 'YOUR_WEBSERVICE_URL'+ '?type=' + XYZ;
  req.setEndPoint(requrl);
  HTTPResponse res;
  if(!Test.isRunningTest()){
   Blob headerValue = Blob.valueOf('YOUR_WEBSERVICE_USERID' +':' +'YOUR_WEBSERVICE_PASSWORD');
   String authorizationHeader = 'Basic ' + EncodingUtil.base64Encode(headerValue);
   req.setHeader('Authorization', authorizationHeader);
   req.setTimeout(120000);
   res = http.send(req);
  }else{
   res = new HttpResponse();
   res.setHeader('Content-Type', 'application/json');
   res.setBody('DUMMY_RESPONSE_IN_CASE_OF_TEST_EXECUTES');
   res.setStatusCode(200);
   res.setStatus('Ok');
  } 
  String resBody;
  if(res != NULL){
   resBody = res.getBody();
   JSONParser parser = JSON.createParser(resBody);
   while (parser.nextToken() != null) {
    /*PROCESS YOUR RESPONSE HEREE */
   }
   ScheduleJob();
  }
  
 }

Here one important point is we are calling the schedulejob method in init again so this is scheduled for next minute.
Now if you start this job at some particular time daily let’s say when business start 10 AM in morning, go to schedule job & schedule a job by using this class. That’s it. The job will start on regular time daily & in code we are having a condition when it will stop. So in this way the job will execute from 10 AM to 8 PM daily.
You can either keep ScheduleJob records for tracking or can delete if not needed. In the above code there is a piece of code which is commented & that is deleting the ScheduleJob object records.

Happy ending! :)

Avoid simultaneous update/ Control same record if already opened by someone in edit mode & show a message to end user

Recently I came across a requirement where client wanted to track if any other user also open the same record to edit, in this case he wanted to show a message to second user so he can edit the same record latter.

To solve this I created a custom setting let’s say Control_Record_Edit__c. Created few other fields to track edit mode –

Name
Edit_DateTime__c
User_Id__c

Name:- field will save record id which is opened in edit mode by someone.
Edit_DateTime__c:- field will tell us how long someone open a record in edit mode
User_Id__c:- field will tell us who open that record in edit mode.


Now let’s say we want to track lead record. We will create a new VF page that will be called LeadEdit.page. In this page we will have a function called init which will basically insert a record in our custom setting, so next time whenever someone open the same lead it edit mode we can check in code & show a message that another user is already opened this lead in edit mode.

<apex:page standardController="lead" extensions="LeadEditController" action="{!init}">
 <apex:form id="form1">
  <apex:outputPanel rendered="{!isNeedToShowMsg}">
   <apex:pageMessages id="error"/>
   <apex:commandButton value="Go To Lead" action="/{!objLead.Id}" style="margin-left: 20px;"/>
  </apex:outputPanel>
 </apex:form>  
</apex:page>


Class code is as below
public with sharing class LeadEditController {
 public Lead objLead {get;set;} 
 public boolean isNeedToShowMsg {get;set;}
 public LeadEditController(ApexPages.StandardController stdController){
  objLead = (Lead)stdController.getRecord();
 }
  
 public PageReference init(){
  isNeedToShowMsg = false;
  PageReference pr = NULL;
  List listOfControlLeadUpdate = [SELECT Id,User_Id__c,Edit_DateTime__c from Control_Lead_Update__c where Name=:objLead.Id and User_Id__c !=:Userinfo.getUserId() LIMIT 1];
  if(listOfControlLeadUpdate != NULL && !listOfControlLeadUpdate.isEmpty()){
   List listOfUser = [Select Id, Name from User where Id=:listOfControlLeadUpdate.get(0).User_Id__c LIMIT 1];
   if(listOfUser != NULL && !listOfUser.isEmpty()){
    String Msg = 'Another User ' + listOfUser.get(0).Name + ' already start editing the same lead at '+  listOfControlLeadUpdate.get(0).Edit_DateTime__c.format()  +', Please wait for sometime & click on edit button again!'; 
    ApexPages.Message apexmsg = new ApexPages.Message(ApexPages.Severity.INFO, Msg);
             ApexPages.addMessage(apexmsg);
             isNeedToShowMsg = true;
   } 
   
  }else{
   Control_Lead_Update__c objControlLead = new Control_Lead_Update__c();
   objControlLead.Name = objLead.Id;
   objControlLead.Edit_DateTime__c = datetime.now();
   objControlLead.User_Id__c = Userinfo.getUserId();
   try{
    insert objControlLead;
   }catch(Exception ex){
    system.debug('exception::-->>>' + ex);
   }
   pr = new PageReference('/' + objLead.Id + '/e?nooverride=1&retURL=/apex/LeadCancel?Id=' + objLead.Id);
  } 
  return pr; 
 }
 
 public PageReference initCancel(){
  LeadHandler.ReleaseEditModeForOthers(new List{objLead});
  PageReference pr = new PageReference('/' + objLead.Id);
  return pr;
 }
}



Here after this one other issue appear when user click on cancel, if user open a lead & click on cancel we should remove his record from custom setting but the problem is cancel override is not available in salesforce. To handle this we created another page that is called LeadCancel & we are passing it in the retURL parameter.

<apex:page standardController="lead" extensions="LeadEditController" action="{!initCancel}">

</apex:page>

now in the class code there is a method initCancel, that is basically deleting the record from custom setting if a user open a lead & click on cancel button. also we are passing this cancel page in retuURL parameter so when user click on cancel it will be back to our page.

There is only one point here which is important, if a user open a lead & close it by browser close button then we can not track that action & in that case no one can edit the same lead until that record does not removed from custom setting.

Tuesday, August 12, 2014

Small Utilities Method


Hi friends, I am back from long time, in between this I could not get a chance to post anything new.
In this post I am showing you small utility methods which we use everyday. This can help if you are looking any quick tip or help -
Map mapOfUserRole = new Map([SELECT Id, Name, ParentRoleId FROM UserRole]);
Map mapOfUserRoleWithHierarchy = new Map();

public void processRoles(){
  String level = '';
  List ListOfUserRole = [SELECT Name, Id FROM UserRole];
  if(ListOfUserRole != NULL && ListOfUserRole.Size()>0){
   for(UserRole u:ListOfUserRole){
    level = processParentRole(u.Id,'');
    if(level != ''){
     mapOfUserRoleWithHierarchy.put(u.Id,level);
     
    }
   }
  }
 }
 
public String processParentRole(Id role, String hierarchyString){
  UserRole userrole = mapOfUserRole.get(role);
  if(userrole.ParentRoleId != NULL){
   hierarchyString += '>>' + userrole.Name;
   return  processParentRole(userrole.ParentRoleId,hierarchyString);  
  }else{
   hierarchyString += '>>'+userrole.Name;
   return hierarchyString;
  }
 }
 
processRoles();
here if you debug mapOfUserRoleWithHierarchy map you will see something like below -
00EXXXXXXXX=>>Team1>>Team2>>Team3>>Team4>>CEO
here I am assuming that hierarchy in your system something like
    -CEO
       -Team4
          -Team3
             -Team2
                -Team1     
Hope this can help if you are doing some code & need something related to user role hierarchy! will keep adding other util method in this post so this can be used kind of quick reference:)

Wednesday, August 7, 2013

How to give a name while export a file in csv/xls

Hi friends, recently I came across a situation where client want's to give a name while exporting a file in csv/xls. In salesforce we can not code in such a way that it will ask you any name before save the file at your local drive. Alternate solution is we can pass different names from the different pages, so we can distinguish in between two exported files from different pages. Here is the detail how you can do this.

We need to create below resources for it-

#1-BlogCSV.page
#2-BlogCSV.component
#3-BlogCSVController.cls
#4-ExportTestPage.page


let me take this one by one & tell you how we can pass name while export in this.

#1-BlogCSV.page 
This is a VF page which generate a xls file for given table.
here the important thing is we will pass contenttype attribute something like below





contentType="application/vnd.ms-excel#{!SUBSTITUTE($CurrentPage.parameters.page,'XXXXXX__','')}_YOUR_POSTFIX_HERE.xls"

in this the exported file name will be build by Page Name from where it is exported + your postfix whatever you give in above content type attribute.

here is the complete code for this-
<apex:page language="en-US" cache="false" readonly="true" sidebar="false" showHeader="false" pageStyle="false" contentType="application/vnd.ms-excel#{!SUBSTITUTE($CurrentPage.parameters.page,'PackagePrefix__','')}_YOUR_POSTFIX_HERE.xls">
  <c:BlogCSV id="csvComponent1" />
</apex:page>


#2-BlogCSV.component 
this component is simply rendering the account table which will be going to export.
<apex:component controller="BlogCSVController" id="component1">
 <apex:pageBlock >
        <apex:pageBlockTable value="{!lstOfAccount}" var="lst" width="100%" rendered="{!IF(lstOfAccount.Size>0,true,false)}">
         <apex:column >
                  <apex:facet name="header" >
                    Name
                  </apex:facet>
                  <apex:outputLink value="{!lst.id}" >{!lst.Name}</apex:outputLink>  
              </apex:column>
              <apex:column >
                  <apex:facet name="header" > 
                     AccountSource
                  </apex:facet>
                  <apex:outputLabel value="{!lst.AccountSource}" />  
              </apex:column>
        </apex:pageBlockTable>
    </apex:pageBlock>    
</apex:component>

#3-BlogCSVController.cls
this class is common controller class for both component & page. here is the code for this -
public with sharing class BlogCSVController {
 public string currentPage {get;set;} 
 public String redirectURL {get;set;}
  public PageReference Export(){
     
     
     PageReference pr = Page.BlogCSV;
     pr.getParameters().put('page',currentPage);
     redirectURL = pr.getUrl(); 
     return null; 
    }
    
 public List lstOfAccount{get;set;}
 public BlogCSVController(){
  lstOfAccount = [Select Id,Name, AccountSource from Account LIMIT 10];
 }
}

#4-ExportTestPage.page
finally this is the page where will provide export button which will initiate export.Here is the code-
<apex:page controller="BlogCSVController">
 <apex:form id="form1">
  <apex:pageMessages id="msg" />
  <apex:sectionHeader Title="Export" subtitle="XLS Sample" /> 
  <apex:pageBlock id="block1">
   <apex:pageBlockButtons location="top">
    <input type="button" class="btn" value="Export" onclick="Export('{!$CurrentPage.Name}');" />
                  <apex:actionStatus id="statusLoadingMain">
                      <apex:facet name="start">
                              <span style="font-weight:bold; color: red;">
                                  Please wait while exporting...<img src="/img/loading.gif" /> 
                              </span> 
                      </apex:facet>
                  </apex:actionStatus>
              </apex:pageBlockButtons>
   
   <script>
     function Export(pagename){
             jsExport(pagename);
          } 
   </script>
    
    <apex:outputPanel id="pnlExport"> 
             <script>
                 if("{!redirectURL}" != ""){
                     window.location.href="{!redirectURL}";
                 }
             </script>
         </apex:outputPanel>
         <apex:actionFunction status="statusLoadingMain" name="jsExport" action="{!Export}" rerender="pnlExport,msg">
                     <apex:param name="currentPage" id="currentPage" value="" assignto="{!currentPage}" />
                   </apex:actionFunction>
   </apex:pageBlock>     
   <c:BlogCSV id="csvComponent1" />    
 </apex:form>          
</apex:page>

here notice that we are passing current page name in action function.
Now when you click on export this will be exported with your page name & given postfix.
You can see a demo here


Wednesday, February 27, 2013

SOQL Injection

Hi friends, 

While writing dynamic SOQL query, I came to know that we should care about the injection script. I tried to get the way how one can write this kind of script so code starts giving unexpected result. I did a lot of rnd on internet but I found the same sample everywhere which is given in salesforce pdf file, but still I was not getting the practical example that satisfy my SOQL injection doubt. 

Because of this reason I created a sample to clear my self what is SOQL injection & how this can give you unexpected result. Here I am sharing it with you so you will get an idea what does SOQL injection means.

You can see demo here. There are four buttons in this page. these are quite simple & self explanatory but let me explain in detail if you have any doubt-
Button -1 Execute
This button shows how simple dynamic query works if we use Equal comparison

Button -2 Execute Like
This button shows how simple dynamic query works if we use LIKE comparison

Button -3 Execute Escape
This button show how dynamic query works if we use String.escapeSingleQuotes method in case of equal comparison

Button -4 Execute Like Escape
This button show how dynamic query works if we use String.escapeSingleQuotes method in case of LIKE comparison

salesforce recommend to use String.escapeSingleQuotes method if you are writing dynamic query.

Now If you open this page & enter the text just after the button "Account1' OR name<>'abc" & click on all four buttons & see the output difference. 

In the first two buttons we are not using escapeSingleQuotes while in the last two buttons we are using escapeSingleQuotes method. 

here when we give injection script (Account1' OR name<>'abc) first two button show all account in the system, that should not be. while in the last two buttons because we are using escapeSingleQuotes method that does not allow to execute this injection script.

here is the code of page & class-
SOQL.page

<apex:page controller="SOQLController" tabStyle="Account">
 <apex:form id="form1">
  <apex:pageBlock id="block1">
    <apex:inputText value="{!name}" />
    <apex:commandButton value="Execute" action="{!Execute}" rerender="pnl" />
    <apex:commandButton value="Execute Like" action="{!ExecuteLike}" rerender="pnl" />  
    <apex:commandButton value="Execute Escape" action="{!ExecuteEscape}" rerender="pnl" />
    <apex:commandButton value="Execute Like Escape" action="{!ExecuteLikeEscape}" rerender="pnl" /> <apex:outputLabel value="Account1' OR name<>'abc"></apex:outputLabel>
    <apex:outputPanel id="pnl">
    <apex:pageBlockTable value="{!lstAccount}" var="lst" id="tbl">
     <apex:column value="{!lst.Name}" /> 
    </apex:pageBlockTable>
    <apex:pageBlockSection title="Query" columns="1">
     <apex:outputLabel value="{!query}"  id="qry"/>
    </apex:pageBlockSection> 
   </apex:outputPanel> 
  </apex:pageBlock>
 </apex:form>
</apex:page>

& class code.. SOQLController.cls
public with sharing class SOQLController {
 public List<Account> lstAccount{get;set;}
 public string query {get;set;}
 public String name {get;set;}
 public void Execute(){
  String StrName =   '=\'' + name + '\''; 
  query = 'Select Id, Name from Account where name '  + StrName ;
  lstAccount = Database.Query(query);
  //input -- Account1' OR name<>'xxx
 }
 public void ExecuteLike(){
  String StrName =  'LIKE \'%' + name + '%\''; 
  query = 'Select Id, Name from Account where name '+ StrName;
  lstAccount = Database.Query(query);
 }
 public void ExecuteEscape(){
  String StrName =   '=\'' + String.escapeSingleQuotes(name) + '\''; 
  query = 'Select Id, Name from Account where name  '  + StrName;
  lstAccount = Database.Query(query);
 }
 public void ExecuteLikeEscape(){
  String StrName =  'LIKE \'%' + String.escapeSingleQuotes(name) + '%\''; 
  query = 'Select Id, Name from Account where name '  + StrName ;
  lstAccount = Database.Query(query);
 }
}
 

Thursday, February 21, 2013

Show Star Rating as Salesforce Standard Field


Hi friends, this time I am coming with a solution for star rating. if you want to show star rating in a standard salesforce layout in form of column.
Take a look of below image. in this I am showing some rating as like this is a stanadrd field in salesforce.


In above image notice that you rating field is appear same as standard field on UI. here is how you can do this-
Step-1
Create a new page named "StarRating" & a new controller class "StarRatingController" in salesforce.

Step-2
Get a jquery star plugin files from net & upload these files in salesforce static resource. I will also tell you the path one of my page latter from where you can download these files.

Step-3
I assuming that you uploaded two static resource -
a-OrgResource
b-jQueryStarRatingPlugIn

in first zip file we are having all jquery js & css files. although we are going to use few of them.
second one zip file is having all files which we downloaded from jquery plugin site.

Step-4
Copy & paste below code in VF page
<apex:page id="page1" sidebar="false" showHeader="false" standardController="Account" extensions="StarRatingController">
    <apex:styleSheet value="{!URLFOR($Resource.OrgResource,'development-bundle/themes/base/jquery.ui.all.css')}" />
    <apex:styleSheet value="{!URLFOR($Resource.jQueryStarRatingPlugIn,'jquery.ui.stars.css')}" />
    <apex:includeScript value="{!URLFOR($Resource.OrgResource,'js/jquery-1.5.1.js')}" />
    <apex:includeScript value="{!URLFOR($Resource.OrgResource,'development-bundle/ui/jquery.ui.core.js')}" />
    <apex:includeScript value="{!URLFOR($Resource.OrgResource,'development-bundle/ui/jquery.ui.widget.js')}" />
    <apex:includeScript value="{!URLFOR($Resource.jQueryStarRatingPlugIn,'jquery.ui.stars.min.js')}" />
    <style>
        .detailList{
            width:94%;
        }
        .pbBody, .pbBody a, .pbBody td, .lbBody a, .lbBodyDescription, .list .headerRow .noRowsHeader {
         border-bottom: 0 none !important;
        }
    </style>
    <apex:form id="form1">
        <apex:pageBlock > 
        <div id="ep" class="bDetailBlock bPageBlock secondaryPalette">
            <div class="pbSubsection">
                <table cellspacing="0" cellpadding="0" border="0" class="detailList" style="border-bottom:none !important;" >
                    <tbody>
                        <tr>
                            <td class="labelCol">Rating</td>
                            <td class="dataCol col02">
                                <apex:outputPanel >
                                    <div class="divRating">
                                        <apex:selectList value="{!rating}" size="1">
                                            <apex:selectOptions value="{!listOfRatingOptions}" />
                                        </apex:selectList>
                                    </div>  
                                </apex:outputPanel> 
                            </td>
                            <td class="labelCol">&nbsp;</td>
                            <td class="dataCol col02">&nbsp;</td>
                        </tr>
                    </tbody>
                </table>
            </div>
        </div>  
            
          <script>
             jQuery(document).ready(function(){
                     jQuery(".divRating").stars({
                        inputType: "select",
                        cancelShow: false,
                        disabled:true
                     });
                     $(".accountBlock").children().attr('class','');
                     $(".detailList").css('width','94%');
                 });
                     
          </script>
        </apex:pageBlock>
    </apex:form>
</apex:page>
Step-5 Copy & paste below class code in controller which you create few steps back
public with sharing class StarRatingController {
 public integer rating {get;set;}
 public List<SelectOption> listOfRatingOptions {get;set;}
 public StarRatingController(ApexPages.StandardController controller){
  listOfRatingOptions = new List<SelectOption>();
  rating = 3;
  string val = '';
  for(integer i=1;i<=5;i++){
   val = string.valueOf(i);
   listOfRatingOptions.add(new SelectOption(val,val));
  }
 }
}
now you can include this page in account stadarad layout. To add this follow next steps.

Step-6
Click on account tab, this will show you list of account. Open one account & click on Edit Layout link at top left.
Step-7
Add a new section from the layout. Give any name to this section.Uncheck Display Section Header On two check box (Detail page & Edit page). In Layout option select 1-Column option & click on save.

Step-8
Add starRating VF page to this section & set height 20 & width 100%.

Save layout & see that rating is available same as a standard field on account detail.

here is the link of star rating page if you want to see how this looks like.You can also download the static resource files by view source.

The same thing you can also do on any VF page. here is demo page. the code of this demo page is as below-
<apex:page standardController="Account" extensions="SiteStarRatingController" id="page1">
  <apex:sectionHeader title="Site"  subTitle="Star Rating Sample" /> 
  <apex:pageBlock id="block1"> 
   <apex:pageBlockSection columns="1">
    <apex:pageBlockSectionItem >
     <apex:outputLabel value="Account Name" />
     <apex:outputField value="{!act.Name}" />
    </apex:pageBlockSectionItem> 
   </apex:pageBlockSection> 
   <apex:pageBlockSection columns="1">
    <apex:iframe src="/apex/StarRating" height="20px" />
   </apex:pageBlockSection>
   <apex:pageBlockSection columns="1">
    <apex:pageBlockSectionItem >
     <apex:outputLabel value="Type" />
     <apex:outputField value="{!act.Type}" />
    </apex:pageBlockSectionItem> 
    <apex:pageBlockSectionItem >
     <apex:outputLabel value="Description" />
     <apex:outputField value="{!act.Description}" />
    </apex:pageBlockSectionItem>
    <apex:pageBlockSectionItem >
     <apex:outputLabel value="Fax" />
     <apex:outputField value="{!act.Fax}" />
    </apex:pageBlockSectionItem>
   </apex:pageBlockSection> 
  </apex:pageBlock>
</apex:page>
controller class is as below-
public with sharing class SiteStarRatingController {
 public Account act{get;set;}
 public SiteStarRatingController(ApexPages.StandardController controller){
  act = [Select Id,Name,Type, Industry, Fax, Description from Account limit 1];
  
 }
}
Done..!! :)

Sunday, August 12, 2012

Salesforce Deployment - Delete a file through ANT

I usually use the ant for deployment this is easy to use & also take less time then Eclipse deployment. Recently  I required to delete a resource from some salesforec org, & I found that there is no detail mentioned about this topic on internet. I keep digging this & come with the detail how you can delete a resource by ANT.
When we use ant deployment here is the folder hierarchy which we use-
ANT Sample Folder
                >>mypkg Folder
                >>retrieveUnpackaged Folder
                >> removecodepkg Folder [Create this new folder to delete the files]
                >>build.properties files
                >>build.xml

To delete a resource you need to add a destructiveChanges.xml  file in removecodepkg  folder. The destructiveChanges.xml file is same as package.xml. format of this file is as below-

<?xml version="1.0" encoding="UTF-8"?>
<Package xmlns="http://soap.sforce.com/2006/04/metadata">
    <types>
        <members>LoginController</members>
        <members>LoginControllerTest</members>
        <name>ApexClass</name>
    </types>      
   <version>19.0</version>
</Package>

You also need to have a blank package.xml file in the same removecodepkg  folder. Format of the file will be-

<?xml version="1.0" encoding="UTF-8"?>
<Package xmlns="http://soap.sforce.com/2006/04/metadata">
  <version>19.0</version>
</Package>

Now you have two xml files in removecodepkg  folder –
1-destructiveChanges.xml  
 2-package.xml
  
ant is having build.xml file which have all commands can be executed. There will be a command to delete the code-

<target name="undeployCode">

      <sf:deploy username="${sf.username}" password="${sf.password}" serverurl="${sf.serverurl}" deployRoot="removecodepkg"/>
    </target>

  
Now mention the name of the resource in destructiveChanges.xml  file & delete the file from destination org. in our example I am deleting a class LoginController & it’s test class.
You just need to execute below command on ant
>>ant undeployCode