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package sample.jpa.currency;

import java.util.List;
import javax.ejb.Local;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

@Stateless
@Local
public class CurrencyBean implements CurrencyInterface{

 @PersistenceContext(unitName="CurrencyRateUnit")
 private EntityManager em;
	
 public Currency createCurrency(String currencyName, 
                                String countryName, 
			        double rateAgstUSD){
		
  Currency crt1 = em.find(Currency.class, currencyName);

  if(crt1 != null) 
   throw new IllegalArgumentException
   ("Currency already exists: Currency Name ("+currencyName+")");

  Currency crt = new Currency();
		
  crt.setCountryName(countryName);
  crt.setCurrencyName(currencyName);
  crt.setRateAgstUSD(rateAgstUSD);
		

  System.out.println("Persisting Currency Rate entity: 
   (Currency = "+currencyName+")");

  em.persist(crt);

  System.out.println("Persisted successfully Currency entity: 
   (Currency = "+currencyName+")");
  return crt;
	
 }
	
 public List listCurrencies(){
  if(em == null) System.out.println("em is null!!!");

  Query q = em.createQuery("SELECT crt FROM Currency crt");

  List currList = q.getResultList();

  return currList;
 }
	
 public Currency updateCurrency(String currencyName, 
                                double rateAgstUSD){
  if(em == null) System.out.println("em is null!!!");
		
  Currency crt1 = em.find(Currency.class, currencyName);

  if(crt1 == null) throw new IllegalArgumentException
   ("Currency not found: Currency Name ("+currencyName+")");

  crt1.setRateAgstUSD(rateAgstUSD);

  return crt1;
		 
 }
	
 public void deleteCurrency(String currencyName){
  if(em == null) System.out.println("em is null!!!");

  Currency crt1 = em.find(Currency.class, currencyName);

  if(crt1 == null) throw new 
   IllegalArgumentException
   ("Currency not found: Currency Name ("+currencyName+")");

  em.remove(crt1);
 }

 public Currency retrieveCurrency(String currencyName){
  Currency crt1 = em.find(Currency.class, currencyName);
  return crt1;
 }
	
}