31 lines
		
	
	
		
			715 B
		
	
	
	
		
			Java
		
	
	
	
	
	
			
		
		
	
	
			31 lines
		
	
	
		
			715 B
		
	
	
	
		
			Java
		
	
	
	
	
	
| package com.baeldung.dip.daoimplementations;
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| 
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| import com.baeldung.dip.daos.CustomerDao;
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| import com.baeldung.dip.entities.Customer;
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| import java.util.HashMap;
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| import java.util.Map;
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| import java.util.Optional;
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| 
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| public class SimpleCustomerDao implements CustomerDao {
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| 
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|     private Map<Integer, Customer> customers = new HashMap<>();
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| 
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|     public SimpleCustomerDao() {
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| 
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|     }
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| 
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|     public SimpleCustomerDao(Map<Integer, Customer> customers) {
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|         this.customers = customers;
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|     }
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| 
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|     @Override
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|     public Optional<Customer> findById(int id) {
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|         return Optional.ofNullable(customers.get(id));
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|     }
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| 
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|     @Override
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|     public List<Customer> findAll() {
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|         return new ArrayList<>(customers.values());
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|     }
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| }
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