Getting MainAccount for Particular Account Num in class

Getting MainAccount for Particular Account Num: class

public LedgerDimensionAccount getLedgerDimension(AccountNum _accountNum)

{

    MainAccount                 mainAccount;

    RefRecId                    accountStructureId;

    List                        dimensionList = new List(Types::Class);

    DimensionDefaultingEngine   dimensionDefaultingEngine;

    ;

    mainAccount = MainAccount::findByMainAccountId(_accountNum);

    accountStructureId = DimensionHierarchy::getAccountStructure(mainAccount.RecId);

    if(mainAccount)

    {

        dimensionDefaultingEngine = DimensionDefaultingEngine::constructForMainAccountId(mainAccount.RecId, accountStructureId);

        dimensionDefaultingEngine.applyDimensionSources(dimensionList);

    return dimensionDefaultingEngine.getLedgerDimension();

    }

    else

    return 0;

}