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BAEL-1419: Guide to cockroachDB in Java (#3325) 

* adding CockroachDB code

* Fixed database name

* Added handling transaction examples
This commit is contained in:
araknoid 2018-01-06 20:38:33 +01:00 committed by Grzegorz Piwowarek
parent 8108875723
commit fa92d1db3d
6 changed files with 500 additions and 0 deletions
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2
persistence-modules/java-cockroachdb/README.md Normal file
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### Relevant Articles:
- [Guide to CockroachDB in Java](http://www.baeldung.com/)

74
persistence-modules/java-cockroachdb/pom.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>parent-modules</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
<relativePath>../../</relativePath>
</parent>
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<artifactId>java-cockroachdb</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<postgresql.version>42.1.4</postgresql.version>
</properties>
<dependencies>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>${postgresql.version}</version>
</dependency>
</dependencies>
<profiles>
<profile>
<id>integration</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<executions>
<execution>
<phase>integration-test</phase>
<goals>
<goal>test</goal>
</goals>
<configuration>
<excludes>
<exclude>**/*ManualTest.java</exclude>
</excludes>
<includes>
<include>**/*IntegrationTest.java</include>
</includes>
</configuration>
</execution>
</executions>
<configuration>
<systemPropertyVariables>
<test.mime>json</test.mime>
</systemPropertyVariables>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
<repositories>
<repository>
<id>Central</id>
<name>Central</name>
<url>http://repo1.maven.org/maven2/</url>
<layout>default</layout>
</repository>
</repositories>
</project>

43
persistence-modules/java-cockroachdb/src/main/java/com/baeldung/cockroachdb/domain/Article.java Normal file
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package com.baeldung.cockroachdb.domain;
import java.util.UUID;
public class Article {
private UUID id;
private String title;
private String author;
public Article(UUID id, String title, String author) {
this.id = id;
this.title = title;
this.author = author;
}
public UUID getId() {
return id;
}
public void setId(UUID id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}

172
persistence-modules/java-cockroachdb/src/main/java/com/baeldung/cockroachdb/repository/ArticleRepository.java Normal file
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package com.baeldung.cockroachdb.repository;
import com.baeldung.cockroachdb.domain.Article;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
/**
* Repository for the articles table related operations
*/
public class ArticleRepository {
private static final String TABLE_NAME = "articles";
private Connection connection;
public ArticleRepository(Connection connection) {
this.connection = connection;
}
/**
* Creates the articles table.
*/
public void createTable() throws SQLException {
StringBuilder sb = new StringBuilder("CREATE TABLE IF NOT EXISTS ").append(TABLE_NAME)
.append("(id uuid PRIMARY KEY, ")
.append("title string,")
.append("author string)");
final String query = sb.toString();
Statement stmt = connection.createStatement();
stmt.execute(query);
}
/**
* Alter the articles table adding a column
*
* @param columnName Column name of the additional column
* @param columnType Column type of the additional column
* @throws SQLException
*/
public void alterTable(String columnName, String columnType) throws SQLException {
StringBuilder sb = new StringBuilder("ALTER TABLE ").append(TABLE_NAME)
.append(" ADD ")
.append(columnName)
.append(" ")
.append(columnType);
final String query = sb.toString();
Statement stmt = connection.createStatement();
stmt.execute(query);
}
/**
* Insert a new article in the articles table
*
* @param article New article to insert
* @throws SQLException
*/
public void insertArticle(Article article) throws SQLException {
StringBuilder sb = new StringBuilder("INSERT INTO ").append(TABLE_NAME)
.append("(id, title, author) ")
.append("VALUES (?,?,?)");
final String query = sb.toString();
PreparedStatement preparedStatement = connection.prepareStatement(query);
preparedStatement.setString(1, article.getId().toString());
preparedStatement.setString(2, article.getTitle());
preparedStatement.setString(3, article.getAuthor());
preparedStatement.execute();
}
/**
* Select article by Title
*
* @param title title of the article to retrieve
* @return article with the given title
* @throws SQLException
*/
public Article selectByTitle(String title) throws SQLException {
StringBuilder sb = new StringBuilder("SELECT * FROM ").append(TABLE_NAME)
.append(" WHERE title = ?");
final String query = sb.toString();
PreparedStatement preparedStatement = connection.prepareStatement(query);
preparedStatement.setString(1, title);
try (ResultSet rs = preparedStatement.executeQuery()) {
List<Article> articles = new ArrayList<>();
while (rs.next()) {
Article article = new Article(
UUID.fromString(rs.getString("id")),
rs.getString("title"),
rs.getString("author")
);
articles.add(article);
}
return articles.get(0);
}
}
/**
* Select all the articles
*
* @return list of all articles
* @throws SQLException
*/
public List<Article> selectAll() throws SQLException {
StringBuilder sb = new StringBuilder("SELECT * FROM ").append(TABLE_NAME);
final String query = sb.toString();
PreparedStatement preparedStatement = connection.prepareStatement(query);
try (ResultSet rs = preparedStatement.executeQuery()) {
List<Article> articles = new ArrayList<>();
while (rs.next()) {
Article article = new Article(
UUID.fromString(rs.getString("id")),
rs.getString("title"),
rs.getString("author")
);
articles.add(article);
}
return articles;
}
}
/**
* Delete article by title
*
* @param title title of the article to delete
* @throws SQLException
*/
public void deleteArticleByTitle(String title) throws SQLException {
StringBuilder sb = new StringBuilder("DELETE FROM ").append(TABLE_NAME)
.append(" WHERE title = ?");
final String query = sb.toString();
PreparedStatement preparedStatement = connection.prepareStatement(query);
preparedStatement.setString(1, title);
preparedStatement.execute();
}
/**
* Delete all rows in the table
*
* @throws SQLException
*/
public void truncateTable() throws SQLException {
StringBuilder sb = new StringBuilder("TRUNCATE TABLE ").append(TABLE_NAME);
final String query = sb.toString();
Statement stmt = connection.createStatement();
stmt.execute(query);
}
/**
* Delete table
*/
public void deleteTable() throws SQLException {
StringBuilder sb = new StringBuilder("DROP TABLE IF EXISTS ").append(TABLE_NAME);
final String query = sb.toString();
Statement stmt = connection.createStatement();
stmt.execute(query);
}
}

208
persistence-modules/java-cockroachdb/src/test/java/com/baeldung/cockroachdb/ArticleRepositoryIntegrationTest.java Normal file
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package com.baeldung.cockroachdb;
import com.baeldung.cockroachdb.domain.Article;
import com.baeldung.cockroachdb.repository.ArticleRepository;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.postgresql.util.PSQLException;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class ArticleRepositoryIntegrationTest {
private static final String TABLE_NAME = "articles";
private Connection con;
private ArticleRepository articleRepository;
@Before
public void connect() throws Exception {
Class.forName("org.postgresql.Driver");
con = DriverManager.getConnection("jdbc:postgresql://localhost:26257/testdb", "user17", "qwerty");
articleRepository = new ArticleRepository(con);
}
@Test
public void whenCreatingTable_thenCreatedCorrectly() throws Exception {
articleRepository.deleteTable();
articleRepository.createTable();
PreparedStatement preparedStatement = con.prepareStatement("SHOW TABLES");
ResultSet resultSet = preparedStatement.executeQuery();
List<String> tables = new ArrayList<>();
while (resultSet.next()) {
tables.add(resultSet.getString("Table"));
}
assertTrue(tables.stream().anyMatch(t -> t.equals(TABLE_NAME)));
}
@Test
public void whenAlteringTheTable_thenColumnAddedCorrectly() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
String columnName = "creationdate";
articleRepository.alterTable(columnName, "DATE");
String query = "SHOW COLUMNS FROM " + TABLE_NAME;
PreparedStatement preparedStatement = con.prepareStatement(query);
ResultSet resultSet = preparedStatement.executeQuery();
List<String> columns = new ArrayList<>();
while (resultSet.next()) {
columns.add(resultSet.getString("Field"));
}
assertTrue(columns.stream().anyMatch(c -> c.equals(columnName)));
}
@Test
public void whenInsertingNewArticle_thenArticleExists() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
String title = "Guide to CockroachDB in Java";
String author = "baeldung";
Article article = new Article(UUID.randomUUID(), title, author);
articleRepository.insertArticle(article);
Article savedArticle = articleRepository.selectByTitle(title);
assertEquals(article.getTitle(), savedArticle.getTitle());
}
@Test
public void whenSelectingAllArticles_thenAllArticlesAreReturned() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
Article article = new Article(UUID.randomUUID(), "Guide to CockroachDB in Java", "baeldung");
articleRepository.insertArticle(article);
article = new Article(UUID.randomUUID(), "A Guide to MongoDB with Java", "baeldung");
articleRepository.insertArticle(article);
List<Article> savedArticles = articleRepository.selectAll();
assertEquals(2, savedArticles.size());
assertTrue(savedArticles.stream().anyMatch(a -> a.getTitle().equals("Guide to CockroachDB in Java")));
assertTrue(savedArticles.stream().anyMatch(a -> a.getTitle().equals("A Guide to MongoDB with Java")));
}
@Test
public void whenDeletingArticleByTtile_thenArticleIsDeleted() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
Article article = new Article(UUID.randomUUID(), "Guide to CockroachDB in Java", "baeldung");
articleRepository.insertArticle(article);
article = new Article(UUID.randomUUID(), "A Guide to MongoDB with Java", "baeldung");
articleRepository.insertArticle(article);
articleRepository.deleteArticleByTitle("A Guide to MongoDB with Java");
List<Article> savedArticles = articleRepository.selectAll();
assertEquals(1, savedArticles.size());
assertTrue(savedArticles.stream().anyMatch(a -> a.getTitle().equals("Guide to CockroachDB in Java")));
assertFalse(savedArticles.stream().anyMatch(a -> a.getTitle().equals("A Guide to MongoDB with Java")));
}
@Test(expected = PSQLException.class)
public void whenDeletingATable_thenExceptionIfAccessed() throws SQLException {
articleRepository.createTable();
articleRepository.deleteTable();
StringBuilder sb = new StringBuilder("SELECT * FROM ").append(TABLE_NAME);
final String query = sb.toString();
PreparedStatement preparedStatement = con.prepareStatement(query);
preparedStatement.executeQuery();
}
@Test
public void whenTruncatingATable_thenEmptyTable() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
Article article = new Article(UUID.randomUUID(), "Guide to CockroachDB in Java", "baeldung");
articleRepository.insertArticle(article);
article = new Article(UUID.randomUUID(), "A Guide to MongoDB with Java", "baeldung");
articleRepository.insertArticle(article);
articleRepository.truncateTable();
List<Article> savedArticles = articleRepository.selectAll();
assertEquals(0, savedArticles.size());
}
@Test
public void whenInsertingTwoArticlesWithSamePrimaryKeyInASingleTransaction_thenRollback() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
try {
con.setAutoCommit(false);
UUID articleId = UUID.randomUUID();
Article article = new Article(articleId, "Guide to CockroachDB in Java", "baeldung");
articleRepository.insertArticle(article);
article = new Article(articleId, "A Guide to MongoDB with Java", "baeldung");
articleRepository.insertArticle(article);
con.commit();
} catch (Exception e) {
con.rollback();
} finally {
con.setAutoCommit(true);
}
List<Article> savedArticles = articleRepository.selectAll();
assertEquals(0, savedArticles.size());
}
@Test
public void whenInsertingTwoArticlesInASingleTransaction_thenInserted() throws SQLException {
articleRepository.deleteTable();
articleRepository.createTable();
try {
con.setAutoCommit(false);
Article article = new Article(UUID.randomUUID(), "Guide to CockroachDB in Java", "baeldung");
articleRepository.insertArticle(article);
article = new Article(UUID.randomUUID(), "A Guide to MongoDB with Java", "baeldung");
articleRepository.insertArticle(article);
con.commit();
} catch (Exception e) {
con.rollback();
} finally {
con.setAutoCommit(true);
}
List<Article> savedArticles = articleRepository.selectAll();
assertEquals(2, savedArticles.size());
assertTrue(savedArticles.stream().anyMatch(a -> a.getTitle().equals("Guide to CockroachDB in Java")));
assertTrue(savedArticles.stream().anyMatch(a -> a.getTitle().equals("A Guide to MongoDB with Java")));
}
@After
public void disconnect() throws SQLException {
articleRepository = null;
con.close();
con = null;
}
}

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pom.xml
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<module>deeplearning4j</module> <module>deeplearning4j</module>
<module>lucene</module> <module>lucene</module>
<module>vraptor</module> <module>vraptor</module>
<module>persistence-modules/java-cockroachdb</module>
</modules> </modules>
<dependencies> <dependencies>