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JDBC removed...

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This commit is contained in:
Amit Dixit 2016-04-04 12:24:15 +05:30
parent 28a5a43a47
commit deb15e2733
5 changed files with 433 additions and 541 deletions
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11
data-mapper/src/main/java/com/iluwatar/datamapper/App.java
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@ -19,7 +19,6 @@
package com.iluwatar.datamapper; package com.iluwatar.datamapper;
import java.util.Optional; import java.util.Optional;
import java.util.UUID;
import org.apache.log4j.Logger; import org.apache.log4j.Logger;
@ -32,7 +31,7 @@ import org.apache.log4j.Logger;
* database schema is always ignorant of the objects that use it.) Since it's a form of Mapper , * database schema is always ignorant of the objects that use it.) Since it's a form of Mapper ,
* Data Mapper itself is even unknown to the domain layer. * Data Mapper itself is even unknown to the domain layer.
* <p> * <p>
* The below example demonstrates basic CRUD operations: select, add, update, and delete. * The below example demonstrates basic CRUD operations: Create, Read, Update, and Delete.
* *
*/ */
public final class App { public final class App {
@ -75,24 +74,24 @@ public final class App {
} else { } else {
/* Don't couple any Data Mapper to java.sql.SQLException */ /* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Following data source(" + args[0] + ") is not supported"); throw new DataMapperException("Following data mapping type(" + args[0] + ") is not supported");
} }
/* Create new student */ /* Create new student */
Student student = new Student(UUID.randomUUID(), 1, "Adam", 'A'); Student student = new Student(1, "Adam", 'A');
/* Add student in respectibe db */ /* Add student in respectibe db */
mapper.insert(student); mapper.insert(student);
/* Find this student */ /* Find this student */
final Optional<Student> studentToBeFound = mapper.find(student.getGuId()); final Optional<Student> studentToBeFound = mapper.find(student.getStudentId());
if (log.isDebugEnabled()) { if (log.isDebugEnabled()) {
log.debug("App.main(), db find returned : " + studentToBeFound); log.debug("App.main(), db find returned : " + studentToBeFound);
} }
/* Update existing student object */ /* Update existing student object */
student = new Student(student.getGuId(), 1, "AdamUpdated", 'A'); student = new Student(student.getStudentId(), "AdamUpdated", 'A');
/* Update student in respectibe db */ /* Update student in respectibe db */
mapper.update(student); mapper.update(student);

56
data-mapper/src/main/java/com/iluwatar/datamapper/Student.java
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@ -18,42 +18,35 @@
*/ */
package com.iluwatar.datamapper; package com.iluwatar.datamapper;
import java.io.Serializable; import java.io.Serializable;
import java.util.UUID;
public final class Student implements Serializable { public final class Student implements Serializable {
private static final long serialVersionUID = 1L; private static final long serialVersionUID = 1L;
private UUID guid; private int studentId;
private int studentID;
private String name; private String name;
private char grade; private char grade;
public Student() { public Student() {
this.guid = UUID.randomUUID();
} }
public Student(final UUID guid, final int studentID, final String name, final char grade) { public Student(final int studentId, final String name, final char grade) {
super(); super();
this.guid = guid; this.studentId = studentId;
this.studentID = studentID;
this.name = name; this.name = name;
this.grade = grade; this.grade = grade;
} }
public Student(final UUID guid) {
this.guid = guid;
}
public final int getStudentId() { public final int getStudentId() {
return studentID; return studentId;
} }
public final void setStudentId(final int studentID) { public final void setStudentId(final int studentId) {
this.studentID = studentID; this.studentId = studentId;
} }
public final String getName() { public final String getName() {
@ -72,12 +65,39 @@ public final class Student implements Serializable {
this.grade = grade; this.grade = grade;
} }
public final UUID getGuId() { @Override
return guid; public boolean equals(final Object inputObject) {
boolean isEqual = false;
/* Check if both objects are same */
if (this == inputObject) {
isEqual = true;
}
/* Check if objects belong to same class */
else if (inputObject != null && getClass() == inputObject.getClass()) {
final Student student = (Student) inputObject;
/* If student id matched */
if (this.getStudentId() == student.getStudentId()) {
isEqual = true;
}
}
return isEqual;
}
@Override
public int hashCode() {
/* Student id is assumed to be unique */
return this.getStudentId();
} }
@Override @Override
public final String toString() { public final String toString() {
return "Student [guid=" + guid + ", studentID=" + studentID + ", name=" + name + ", grade=" + grade + "]"; return "Student [studentId=" + studentId + ", name=" + name + ", grade=" + grade + "]";
} }
} }

3
data-mapper/src/main/java/com/iluwatar/datamapper/StudentDataMapper.java
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@ -19,11 +19,10 @@
package com.iluwatar.datamapper; package com.iluwatar.datamapper;
import java.util.Optional; import java.util.Optional;
import java.util.UUID;
public interface StudentDataMapper { public interface StudentDataMapper {
public Optional<Student> find(final UUID uniqueID) throws DataMapperException; public Optional<Student> find(final int studentId);
public void insert(final Student student) throws DataMapperException; public void insert(final Student student) throws DataMapperException;

133
data-mapper/src/main/java/com/iluwatar/datamapper/StudentMySQLDataMapper.java
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@ -18,52 +18,25 @@
*/ */
package com.iluwatar.datamapper; package com.iluwatar.datamapper;
import java.sql.Connection; import java.util.List;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Optional; import java.util.Optional;
import java.util.UUID;
public final class StudentMySQLDataMapper implements StudentDataMapper { public final class StudentMySQLDataMapper implements StudentDataMapper {
/* Note: Normally this would be in the form of an actual database */
private List<Student> students;
@Override @Override
public final Optional<Student> find(final UUID uniqueID) throws DataMapperException { public final Optional<Student> find(final int studentId) {
try { /* Compare with existing students */
/* OracleDriver class cant be initilized directly */ for (final Student student : this.students) {
Class.forName("oracle.jdbc.driver.OracleDriver");
/* Create new connection */ /* Check if student is found */
final Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/MySQL", "username", "password"); if (student.getStudentId() == studentId) {
/* Create new Oracle compliant sql statement */
final String statement = "SELECT `guid`, `grade`, `studentID`, `name` FROM `students` where `guid`=?";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set unique id in sql statement */
dbStatement.setString(1, uniqueID.toString());
/* Execute the sql query */
final ResultSet rs = dbStatement.executeQuery();
while (rs.next()) {
/* Create new student */
final Student student = new Student(UUID.fromString(rs.getString("guid")));
/* Set all values from database in java object */
student.setName(rs.getString("name"));
student.setGrade(rs.getString("grade").charAt(0));
student.setStudentId(rs.getInt("studentID"));
return Optional.of(student); return Optional.of(student);
} }
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from MySQL data source.", e);
} }
/* Return empty value */ /* Return empty value */
@ -71,90 +44,54 @@ public final class StudentMySQLDataMapper implements StudentDataMapper {
} }
@Override @Override
public final void update(final Student student) throws DataMapperException { public final void update(final Student studentToBeUpdated) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */
Class.forName("oracle.jdbc.driver.OracleDriver");
/* Create new connection */ /* Check with existing students */
final Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/MySQL", "username", "password"); if (this.students.contains(studentToBeUpdated)) {
/* Create new Oracle compliant sql statement */ /* Get the index of student in list */
final String statement = "UPDATE `students` SET `grade`=?, `studentID`=?, `name`=? where `guid`=?"; final int index = this.students.indexOf(studentToBeUpdated);
final PreparedStatement dbStatement = connection.prepareStatement(statement); /* Update the student in list */
this.students.set(index, studentToBeUpdated);
/* Set java object values in sql statement */ } else {
dbStatement.setString(1, Character.toString(student.getGrade()));
dbStatement.setInt(2, student.getStudentId());
dbStatement.setString(3, student.getName());
dbStatement.setString(4, student.getGuId().toString());
/* Execute the sql query */ /* Throw user error */
dbStatement.executeUpdate(); throw new DataMapperException("Student [" + studentToBeUpdated.getName() + "] is not found");
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from MySQL data source.", e);
} }
} }
@Override @Override
public final void insert(final Student student) throws DataMapperException { public final void insert(final Student studentToBeInserted) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */ /* Check with existing students */
Class.forName("oracle.jdbc.driver.OracleDriver"); if (!this.students.contains(studentToBeInserted)) {
/* Create new connection */ /* Add student in list */
final Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/MySQL", "username", "password"); this.students.add(studentToBeInserted);
/* Create new Oracle compliant sql statement */ } else {
final String statement = "INSERT INTO `students` (`grade`, `studentID`, `name`, `guid`) VALUES (?, ?, ?, ?)";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set java object values in sql statement */ /* Throw user error */
dbStatement.setString(1, Character.toString(student.getGrade())); throw new DataMapperException("Student already [" + studentToBeInserted.getName() + "] exists");
dbStatement.setInt(2, student.getStudentId());
dbStatement.setString(3, student.getName());
dbStatement.setString(4, student.getGuId().toString());
/* Execute the sql query */
dbStatement.executeUpdate();
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from MySQL data source.", e);
} }
} }
@Override @Override
public final void delete(final Student student) throws DataMapperException { public final void delete(final Student studentToBeDeleted) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */ /* Check with existing students */
Class.forName("oracle.jdbc.driver.OracleDriver"); if (this.students.contains(studentToBeDeleted)) {
/* Create new connection */ /* Delete the student from list */
final Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/MySQL", "username", "password"); this.students.remove(studentToBeDeleted);
/* Create new Oracle compliant sql statement */ } else {
final String statement = "DELETE FROM `students` where `guid`=?";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set java object values in sql statement */ /* Throw user error */
dbStatement.setString(1, student.getGuId().toString()); throw new DataMapperException("Student [" + studentToBeDeleted.getName() + "] is not found");
/* Execute the sql query */
dbStatement.executeUpdate();
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from MySQL data source.", e);
} }
} }
} }

133
data-mapper/src/main/java/com/iluwatar/datamapper/StudentOracleDataMapper.java
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@ -18,52 +18,25 @@
*/ */
package com.iluwatar.datamapper; package com.iluwatar.datamapper;
import java.sql.Connection; import java.util.List;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Optional; import java.util.Optional;
import java.util.UUID;
public final class StudentOracleDataMapper implements StudentDataMapper { public final class StudentOracleDataMapper implements StudentDataMapper {
/* Note: Normally this would be in the form of an actual database */
private List<Student> students;
@Override @Override
public final Optional<Student> find(final UUID uniqueID) throws DataMapperException { public final Optional<Student> find(final int studentId) {
try { /* Compare with existing students */
/* OracleDriver class cant be initilized directly */ for (final Student student : this.students) {
Class.forName("oracle.jdbc.driver.OracleDriver");
/* Create new connection */ /* Check if student is found */
final Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:Oracle", "username", "password"); if (student.getStudentId() == studentId) {
/* Create new Oracle compliant sql statement */
final String statement = "SELECT `guid`, `grade`, `studentID`, `name` FROM `students` where `guid`=?";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set unique id in sql statement */
dbStatement.setString(1, uniqueID.toString());
/* Execute the sql query */
final ResultSet rs = dbStatement.executeQuery();
while (rs.next()) {
/* Create new student */
final Student student = new Student(UUID.fromString(rs.getString("guid")));
/* Set all values from database in java object */
student.setName(rs.getString("name"));
student.setGrade(rs.getString("grade").charAt(0));
student.setStudentId(rs.getInt("studentID"));
return Optional.of(student); return Optional.of(student);
} }
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from Oracle data source.", e);
} }
/* Return empty value */ /* Return empty value */
@ -71,90 +44,54 @@ public final class StudentOracleDataMapper implements StudentDataMapper {
} }
@Override @Override
public final void update(final Student student) throws DataMapperException { public final void update(final Student studentToBeUpdated) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */
Class.forName("oracle.jdbc.driver.OracleDriver");
/* Create new connection */ /* Check with existing students */
final Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:Oracle", "username", "password"); if (this.students.contains(studentToBeUpdated)) {
/* Create new Oracle compliant sql statement */ /* Get the index of student in list */
final String statement = "UPDATE `students` SET `grade`=?, `studentID`=?, `name`=? where `guid`=?"; final int index = this.students.indexOf(studentToBeUpdated);
final PreparedStatement dbStatement = connection.prepareStatement(statement); /* Update the student in list */
this.students.set(index, studentToBeUpdated);
/* Set java object values in sql statement */ } else {
dbStatement.setString(1, Character.toString(student.getGrade()));
dbStatement.setInt(2, student.getStudentId());
dbStatement.setString(3, student.getName());
dbStatement.setString(4, student.getGuId().toString());
/* Execute the sql query */ /* Throw user error */
dbStatement.executeUpdate(); throw new DataMapperException("Student [" + studentToBeUpdated.getName() + "] is not found");
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from Oracle data source.", e);
} }
} }
@Override @Override
public final void insert(final Student student) throws DataMapperException { public final void insert(final Student studentToBeInserted) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */ /* Check with existing students */
Class.forName("oracle.jdbc.driver.OracleDriver"); if (!this.students.contains(studentToBeInserted)) {
/* Create new connection */ /* Add student in list */
final Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:Oracle", "username", "password"); this.students.add(studentToBeInserted);
/* Create new Oracle compliant sql statement */ } else {
final String statement = "INSERT INTO `students` (`grade`, `studentID`, `name`, `guid`) VALUES (?, ?, ?, ?)";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set java object values in sql statement */ /* Throw user error */
dbStatement.setString(1, Character.toString(student.getGrade())); throw new DataMapperException("Student already [" + studentToBeInserted.getName() + "] exists");
dbStatement.setInt(2, student.getStudentId());
dbStatement.setString(3, student.getName());
dbStatement.setString(4, student.getGuId().toString());
/* Execute the sql query */
dbStatement.executeUpdate();
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from Oracle data source.", e);
} }
} }
@Override @Override
public final void delete(final Student student) throws DataMapperException { public final void delete(final Student studentToBeDeleted) throws DataMapperException {
try {
/* OracleDriver class cant be initilized directly */ /* Check with existing students */
Class.forName("oracle.jdbc.driver.OracleDriver"); if (this.students.contains(studentToBeDeleted)) {
/* Create new connection */ /* Delete the student from list */
final Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:Oracle", "username", "password"); this.students.remove(studentToBeDeleted);
/* Create new Oracle compliant sql statement */ } else {
final String statement = "DELETE FROM `students` where `guid`=?";
final PreparedStatement dbStatement = connection.prepareStatement(statement);
/* Set java object values in sql statement */ /* Throw user error */
dbStatement.setString(1, student.getGuId().toString()); throw new DataMapperException("Student [" + studentToBeDeleted.getName() + "] is not found");
/* Execute the sql query */
dbStatement.executeUpdate();
} catch (final SQLException | ClassNotFoundException e) {
/* Don't couple any Data Mapper to java.sql.SQLException */
throw new DataMapperException("Error occured reading Students from Oracle data source.", e);
} }
} }
} }