Toby/chapter3 7

spring-toby/java-project/src/main/java/com/javabom/toby/chapter3/pattern/템플릿_콜백_패턴/Calculator.java

@@ -0,0 +1,23 @@
+package com.javabom.toby.chapter3.pattern.템플릿_콜백_패턴;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+public class Calculator {
+    public Integer calcSum(InputStream in) throws IOException {
+        /*
+         * 콜백: 메서드에 전달되는 오브젝트. 파라미터지만 값이아니라 특정로직이다.
+         * 변하는 부분을 콜백으로 전달한다.
+         * - line, value는 컨텍스트 정보를 전달하는 매개변수이다. 콜백은 이 정보들을 참조하여 템플릿에 전달된다.
+         */
+        LineCallback sumCallBack = (line, value) -> value + Integer.parseInt(line);
+        return StreamReaderTemplate.lineReadTemplate(in, sumCallBack, 0);
+    }
+
+    /*
+        익명클래스로 넣을 때 메모리 저장 시점
+     */
+    public Integer calcMultiply(InputStream in) throws IOException {
+        return StreamReaderTemplate.lineReadTemplate(in, (line, value) -> value * Integer.parseInt(line), 1);
+    }
+}

spring-toby/java-project/src/main/java/com/javabom/toby/chapter3/pattern/템플릿_콜백_패턴/LineCallback.java

@@ -0,0 +1,5 @@
+package com.javabom.toby.chapter3.pattern.템플릿_콜백_패턴;
+
+public interface LineCallback {
+    Integer doSomethingWithLine(String line, Integer value);
+}

spring-toby/java-project/src/main/java/com/javabom/toby/chapter3/pattern/템플릿_콜백_패턴/StreamReaderTemplate.java

@@ -0,0 +1,38 @@
+package com.javabom.toby.chapter3.pattern.템플릿_콜백_패턴;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Objects;
+
+public class StreamReaderTemplate {
+
+    /**
+     * 템플릿: Calculator 에서 행해지는 연산들에 공통으로 필요한 코드를 템플릿으로 정의한다.
+     * 여기서는 InputStream 에서 한줄씩 읽으며 try-catch-finally 로 묶인 일련의 과정이 속한다.
+     */
+    public static Integer lineReadTemplate(InputStream in, LineCallback lineCallback, int initVal) throws IOException {
+        BufferedReader br = null;
+        try {
+            br = new BufferedReader(new InputStreamReader(in));
+            Integer res = initVal;
+            String line;
+            while ((line = br.readLine()) != null) {
+                res = lineCallback.doSomethingWithLine(line, res);
+            }
+            return res;
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+            throw e;
+        } finally {
+            if (Objects.nonNull(br)) {
+                try {
+                    br.close();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
+}

spring-toby/java-project/src/test/java/com/javabom/toby/chapter3/pattern/템플릿_콜백_패턴/CalculatorTest.java

@@ -0,0 +1,24 @@
+package com.javabom.toby.chapter3.pattern.템플릿_콜백_패턴;
+
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class CalculatorTest {
+
+    @DisplayName("덧셈, 곱셈, 템플릿콜백패턴")
+    @Test
+    void test() throws IOException {
+        Calculator calculator = new Calculator();
+        Integer sum = calculator.calcSum(getClass().getClassLoader().getResourceAsStream("chapter3/calcSample.txt"));
+        Integer multiply = calculator.calcMultiply(getClass().getClassLoader().getResourceAsStream("chapter3/calcSample.txt"));
+
+        assertThat(sum).isEqualTo(6);
+        assertThat(multiply).isEqualTo(6);
+    }
+
+}

spring-toby/java-project/src/test/resources/chapter3/calcSample.txt

@@ -0,0 +1,3 @@
+1
+2
+3

spring-toby/spring-project/src/main/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/Chapter3UserDao.java

@@ -0,0 +1,21 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import org.springframework.jdbc.core.JdbcTemplate;
+
+import javax.sql.DataSource;
+
+public class Chapter3UserDao {
+    private JdbcTemplate jdbcTemplate;
+
+    public void setDataSource(DataSource dataSource) {
+        this.jdbcTemplate = new JdbcTemplate(dataSource);
+    }
+
+    public void add(TobyUser user) {
+        jdbcTemplate.update("INSERT INTO TOBY_USER VALUES (?, ?, ?)", user.getId(), user.getName(), user.getPassword());
+    }
+
+    public void get(final String id) {
+
+    }
+}

spring-toby/spring-project/src/main/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/JdbcContext.java

@@ -0,0 +1,31 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+
+public class JdbcContext {
+    private final DataSource dataSource;
+
+    public JdbcContext(DataSource dataSource) {
+        this.dataSource = dataSource;
+    }
+
+    /*
+    변하지 않는 템플릿
+     */
+    public void workWithStatementStrategy(StatementStrategy statementStrategy) throws SQLException {
+        Connection connection = null;
+        try {
+            connection = dataSource.getConnection();
+            // 콜백 파라미터로 현재 컨텍스트의 Connection 을 넘긴다
+            statementStrategy.makePreparedStatement(connection).executeUpdate();
+        } catch (SQLException throwables) {
+
+
+        } finally {
+            connection.close();
+        }
+
+    }
+}

spring-toby/spring-project/src/main/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/StatementStrategy.java

@@ -0,0 +1,9 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+public interface StatementStrategy {
+    PreparedStatement makePreparedStatement(Connection c) throws SQLException;
+}

spring-toby/spring-project/src/main/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/TobyUser.java

@@ -0,0 +1,16 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import lombok.Getter;
+
+@Getter
+public class TobyUser {
+    private String id;
+    private String name;
+    private String password;
+
+    public TobyUser(final String id, final String name, final String password) {
+        this.id = id;
+        this.name = name;
+        this.password = password;
+    }
+}

spring-toby/spring-project/src/main/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/UserDaoWithTemplateCallback.java

@@ -0,0 +1,17 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import java.sql.SQLException;
+
+public class UserDaoWithTemplateCallback {
+    private final JdbcContext jdbcContext;
+
+    public UserDaoWithTemplateCallback(JdbcContext jdbcContext) {
+        this.jdbcContext = jdbcContext;
+    }
+
+    public void deleteAll() throws SQLException {
+        this.jdbcContext.workWithStatementStrategy(
+                c -> c.prepareStatement("delete from users")); // 변하는 부분을 콜백으로 뺀다
+    }
+
+}

spring-toby/spring-project/src/main/java/com/javabom/toby/user/dao/DaoFactory.java

@@ -22,7 +22,6 @@ public UserDao userDao() {
     public UserDao dataSourceUserDao() {
         UserDao userDao = new UserDao();
         userDao.setDataSource(dataSource());
-        userDao.setJdbcContext(jdbcContext());
         return userDao;
     }
 

spring-toby/spring-project/src/main/resources/applicationContext.xml

@@ -10,6 +10,10 @@
         <property name="connectionMaker" ref="localDBConnectionMaker"/>
     </bean>
 
+    <bean id="tobyUserDao" class="com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴.Chapter3UserDao">
+        <property name="dataSource" ref="dataSource"/>
+    </bean>
+
     <bean id="dataSourceUserDao" class="com.javabom.toby.user.dao.UserDao">
         <property name="dataSource" ref="dataSource"/>
     </bean>

spring-toby/spring-project/src/test/java/com/javabom/toby/chapter3/jdbc_템플릿_콜백_패턴/TobyUserDaoTest.java

@@ -0,0 +1,24 @@
+package com.javabom.toby.chapter3.jdbc_템플릿_콜백_패턴;
+
+import jdk.nashorn.internal.ir.annotations.Ignore;
+import org.junit.jupiter.api.DisplayName;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ContextConfiguration;
+
+@SpringBootTest
+@ContextConfiguration("/applicationContext.xml")
+class TobyUserDaoTest {
+    Chapter3UserDao chapter3UserDao = new Chapter3UserDao();
+
+    @DisplayName("유저 저장테스트")
+    @Ignore
+    void add() {
+        /*
+         * 네거티브 테스트
+         * 예외상항에 대한 테스트
+         */
+        chapter3UserDao.add(null);
+        chapter3UserDao.get("unknown");
+    }
+
+}