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Merge pull request iluwatar#407 from iluwatar/refactor-dao
Solves iluwatar#404 Refactor dao
2 parents d406f0f + 464ae16 commit d20145c

16 files changed

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-261
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‎dao/etc/dao.png

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‎dao/etc/dao.ucls

Lines changed: 46 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -1,45 +1,71 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<class-diagram version="1.1.8" icons="true" always-add-relationships="false" generalizations="true" realizations="true"
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associations="true" dependencies="false" nesting-relationships="true">
4-
<class id="1" language="java" name="com.iluwatar.Customer" project="dao"
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file="/dao/src/main/java/com/iluwatar/Customer.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="176" y="337"/>
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<class id="1" language="java" name="com.iluwatar.dao.App" project="dao"
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file="/dao/src/main/java/com/iluwatar/dao/App.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="910" y="191"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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<attributes public="true" package="true" protected="true" private="false" static="true"/>
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<operations public="true" package="true" protected="true" private="false" static="true"/>
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</display>
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</class>
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<class id="2" language="java" name="com.iluwatar.CustomerDaoImpl" project="dao"
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file="/dao/src/main/java/com/iluwatar/CustomerDaoImpl.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="540" y="334"/>
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<interface id="2" language="java" name="com.iluwatar.dao.CustomerDao" project="dao"
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file="/dao/src/main/java/com/iluwatar/dao/CustomerDao.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="536" y="187"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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</display>
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</interface>
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<class id="3" language="java" name="com.iluwatar.dao.InMemoryCustomerDao" project="dao"
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file="/dao/src/main/java/com/iluwatar/dao/InMemoryCustomerDao.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="289" y="455"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="false" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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</display>
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</class>
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<interface id="3" language="java" name="com.iluwatar.CustomerDao" project="dao"
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file="/dao/src/main/java/com/iluwatar/CustomerDao.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="536" y="131"/>
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<class id="4" language="java" name="com.iluwatar.dao.DBCustomerDao" project="dao"
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file="/dao/src/main/java/com/iluwatar/dao/DBCustomerDao.java" binary="false" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="751" y="456"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="false" static="true"/>
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<operations public="true" package="true" protected="true" private="false" static="true"/>
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</display>
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</class>
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<interface id="5" language="java" name="javax.sql.DataSource" project="dao"
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file="/opt/Softwares/Eclipses/MARS/eclipse/jre/lib/rt.jar" binary="true" corner="BOTTOM_RIGHT">
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<position height="-1" width="-1" x="1083" y="459"/>
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<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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</display>
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</interface>
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<realization id="4">
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<end type="SOURCE" refId="2"/>
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<end type="TARGET" refId="3"/>
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</realization>
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<association id="5">
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<end type="SOURCE" refId="2" navigable="false">
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<attribute id="6" name="customers"/>
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<multiplicity id="7" minimum="0" maximum="2147483647"/>
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<association id="6">
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<end type="SOURCE" refId="4" navigable="false">
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<attribute id="7" name="dataSource"/>
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<multiplicity id="8" minimum="0" maximum="1"/>
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</end>
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<end type="TARGET" refId="1" navigable="true"/>
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<end type="TARGET" refId="5" navigable="true"/>
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<display labels="true" multiplicity="true"/>
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</association>
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<realization id="9">
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<end type="SOURCE" refId="3"/>
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<end type="TARGET" refId="2"/>
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</realization>
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<dependency id="10">
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<end type="SOURCE" refId="1"/>
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<end type="TARGET" refId="2"/>
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</dependency>
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<realization id="11">
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<end type="SOURCE" refId="4"/>
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<end type="TARGET" refId="2"/>
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</realization>
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<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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sort-features="false" accessors="true" visibility="true">
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<attributes public="true" package="true" protected="true" private="true" static="true"/>

‎dao/pom.xml

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Original file line numberDiff line numberDiff line change
@@ -44,6 +44,18 @@
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<groupId>log4j</groupId>
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<artifactId>log4j</artifactId>
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</dependency>
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<dependency>
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<groupId>com.h2database</groupId>
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<artifactId>h2</artifactId>
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</dependency>
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<dependency>
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<groupId>de.bechte.junit</groupId>
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<artifactId>junit-hierarchicalcontextrunner</artifactId>
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</dependency>
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<dependency>
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<groupId>org.mockito</groupId>
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<artifactId>mockito-core</artifactId>
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</dependency>
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</dependencies>
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<build>

‎dao/src/main/java/com/iluwatar/dao/App.java

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Original file line numberDiff line numberDiff line change
@@ -20,49 +20,101 @@
2020
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
2222
*/
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package com.iluwatar.dao;
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26+
import java.sql.Connection;
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import java.sql.SQLException;
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import java.sql.Statement;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.stream.Stream;
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import javax.sql.DataSource;
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import org.apache.log4j.Logger;
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import org.h2.jdbcx.JdbcDataSource;
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/**
31-
*
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* Data Access Object (DAO) is an object that provides an abstract interface to some type of
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* database or other persistence mechanism. By mapping application calls to the persistence layer,
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* DAO provide some specific data operations without exposing details of the database. This
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* isolation supports the Single responsibility principle. It separates what data accesses the
3643
* application needs, in terms of domain-specific objects and data types (the public interface of
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* the DAO), from how these needs can be satisfied with a specific DBMS.
38-
* <p>
39-
* With the DAO pattern, we can use various method calls to retrieve/add/delete/update data without
40-
* directly interacting with the data. The below example demonstrates basic CRUD operations: select,
41-
* add, update, and delete.
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*
46+
* <p>With the DAO pattern, we can use various method calls to retrieve/add/delete/update data
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* without directly interacting with the data source. The below example demonstrates basic CRUD
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* operations: select, add, update, and delete.
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*
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*
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*/
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public class App {
45-
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private static final String DB_URL = "jdbc:h2:~/dao:customerdb";
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private static Logger log = Logger.getLogger(App.class);
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/**
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* Program entry point.
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*
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* @param args command line args.
60+
* @throws Exception if any error occurs.
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*/
53-
public static void main(final String[] args) {
54-
final CustomerDao customerDao = new CustomerDaoImpl(generateSampleCustomers());
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log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
56-
log.info("customerDao.getCusterById(2): " + customerDao.getCustomerById(2));
62+
public static void main(final String[] args) throws Exception {
63+
final CustomerDao inMemoryDao = new InMemoryCustomerDao();
64+
performOperationsUsing(inMemoryDao);
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final DataSource dataSource = createDataSource();
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createSchema(dataSource);
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final CustomerDao dbDao = new DbCustomerDao(dataSource);
69+
performOperationsUsing(dbDao);
70+
deleteSchema(dataSource);
71+
}
72+
73+
private static void deleteSchema(DataSource dataSource) throws SQLException {
74+
try (Connection connection = dataSource.getConnection();
75+
Statement statement = connection.createStatement()) {
76+
statement.execute(CustomerSchemaSql.DELETE_SCHEMA_SQL);
77+
}
78+
}
79+
80+
private static void createSchema(DataSource dataSource) throws SQLException {
81+
try (Connection connection = dataSource.getConnection();
82+
Statement statement = connection.createStatement()) {
83+
statement.execute(CustomerSchemaSql.CREATE_SCHEMA_SQL);
84+
}
85+
}
86+
87+
private static DataSource createDataSource() {
88+
JdbcDataSource dataSource = new JdbcDataSource();
89+
dataSource.setURL(DB_URL);
90+
return dataSource;
91+
}
92+
93+
private static void performOperationsUsing(final CustomerDao customerDao) throws Exception {
94+
addCustomers(customerDao);
95+
log.info("customerDao.getAllCustomers(): ");
96+
try (Stream<Customer> customerStream = customerDao.getAll()) {
97+
customerStream.forEach((customer) -> log.info(customer));
98+
}
99+
log.info("customerDao.getCustomerById(2): " + customerDao.getById(2));
57100
final Customer customer = new Customer(4, "Dan", "Danson");
58-
customerDao.addCustomer(customer);
59-
log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
101+
customerDao.add(customer);
102+
log.info("customerDao.getAllCustomers(): " + customerDao.getAll());
60103
customer.setFirstName("Daniel");
61104
customer.setLastName("Danielson");
62-
customerDao.updateCustomer(customer);
63-
log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
64-
customerDao.deleteCustomer(customer);
65-
log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
105+
customerDao.update(customer);
106+
log.info("customerDao.getAllCustomers(): ");
107+
try (Stream<Customer> customerStream = customerDao.getAll()) {
108+
customerStream.forEach((cust) -> log.info(cust));
109+
}
110+
customerDao.delete(customer);
111+
log.info("customerDao.getAllCustomers(): " + customerDao.getAll());
112+
}
113+
114+
private static void addCustomers(CustomerDao customerDao) throws Exception {
115+
for (Customer customer : generateSampleCustomers()) {
116+
customerDao.add(customer);
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}
66118
}
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/**

‎dao/src/main/java/com/iluwatar/dao/Customer.java

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Original file line numberDiff line numberDiff line change
@@ -20,11 +20,11 @@
2020
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.dao;
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2526
/**
26-
*
27-
* Customer
27+
* A customer POJO that represents the data that will be read from the data source.
2828
*
2929
*/
3030
public class Customer {
@@ -34,7 +34,7 @@ public class Customer {
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private String lastName;
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/**
37-
* Constructor
37+
* Creates an instance of customer.
3838
*/
3939
public Customer(final int id, final String firstName, final String lastName) {
4040
this.id = id;
@@ -73,12 +73,12 @@ public String toString() {
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}
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@Override
76-
public boolean equals(final Object o) {
76+
public boolean equals(final Object that) {
7777
boolean isEqual = false;
78-
if (this == o) {
78+
if (this == that) {
7979
isEqual = true;
80-
} else if (o != null && getClass() == o.getClass()) {
81-
final Customer customer = (Customer) o;
80+
} else if (that != null && getClass() == that.getClass()) {
81+
final Customer customer = (Customer) that;
8282
if (getId() == customer.getId()) {
8383
isEqual = true;
8484
}

‎dao/src/main/java/com/iluwatar/dao/CustomerDao.java

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Original file line numberDiff line numberDiff line change
@@ -20,24 +20,62 @@
2020
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
2222
*/
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package com.iluwatar.dao;
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25-
import java.util.List;
26+
import java.util.Optional;
27+
import java.util.stream.Stream;
2628

2729
/**
30+
* In an application the Data Access Object (DAO) is a part of Data access layer. It is an object
31+
* that provides an interface to some type of persistence mechanism. By mapping application calls
32+
* to the persistence layer, DAO provides some specific data operations without exposing details
33+
* of the database. This isolation supports the Single responsibility principle. It separates what
34+
* data accesses the application needs, in terms of domain-specific objects and data types
35+
* (the public interface of the DAO), from how these needs can be satisfied with a specific DBMS,
36+
* database schema, etc.
2837
*
29-
* CustomerDao
30-
*
38+
* <p>Any change in the way data is stored and retrieved will not change the client code as the
39+
* client will be using interface and need not worry about exact source.
40+
*
41+
* @see InMemoryCustomerDao
42+
* @see DbCustomerDao
3143
*/
3244
public interface CustomerDao {
3345

34-
List<Customer> getAllCustomers();
35-
36-
Customer getCustomerById(int id);
46+
/**
47+
* @return all the customers as a stream. The stream may be lazily or eagerly evaluated based
48+
* on the implementation. The stream must be closed after use.
49+
* @throws Exception if any error occurs.
50+
*/
51+
Stream<Customer> getAll() throws Exception;
52+
53+
/**
54+
* @param id unique identifier of the customer.
55+
* @return an optional with customer if a customer with unique identifier <code>id</code>
56+
* exists, empty optional otherwise.
57+
* @throws Exception if any error occurs.
58+
*/
59+
Optional<Customer> getById(int id) throws Exception;
3760

38-
void addCustomer(Customer customer);
61+
/**
62+
* @param customer the customer to be added.
63+
* @return true if customer is successfully added, false if customer already exists.
64+
* @throws Exception if any error occurs.
65+
*/
66+
boolean add(Customer customer) throws Exception;
3967

40-
void updateCustomer(Customer customer);
68+
/**
69+
* @param customer the customer to be updated.
70+
* @return true if customer exists and is successfully updated, false otherwise.
71+
* @throws Exception if any error occurs.
72+
*/
73+
boolean update(Customer customer) throws Exception;
4174

42-
void deleteCustomer(Customer customer);
75+
/**
76+
* @param customer the customer to be deleted.
77+
* @return true if customer exists and is successfully deleted, false otherwise.
78+
* @throws Exception if any error occurs.
79+
*/
80+
boolean delete(Customer customer) throws Exception;
4381
}

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