Spring Framework 4.1 Udemy Course

Monday, 8 August 2016

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.util.Collection;

import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.demo.hibernate.HibernateConnection;
import com.demo.pojo.User;

public class HibernateDAO<K extends Serializable, T extends Serializable> extends HibernateDaoSupport {

protected Class<T> domainClass = getDomainClass();

protected Class getDomainClass() {
if (domainClass == null) {
ParameterizedType thisType = (ParameterizedType) getClass().getGenericSuperclass();

// get T, so the 2nd class
domainClass = (Class) thisType.getActualTypeArguments()[1];
}
System.out.println("Domain class is -> "+domainClass);
return domainClass;
}

public Object action(TaskManager taskManager){
try{
return taskManager.task();
}catch(Exception e){
e.printStackTrace();
return null;
}
}

public Collection<T> getAll(){
return (Collection<T>)action(new TaskManager() {
public Object task() throws Exception {
return getCachedHibernateTemplate().loadAll(domainClass);
}
});
}

private HibernateTemplate getCachedHibernateTemplate() {
HibernateTemplate template = new HibernateTemplate();
template.setSessionFactory(HibernateConnection.doHibernateConnection());
template.setCacheQueries(true);
return template;
}

public interface TaskManager{
public Object task() throws Exception;
}
}

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import org.springframework.orm.hibernate3.HibernateTemplate;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.sql.SQLException;
import java.util.Collection;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

public abstract class HibernateDAO<K extends Serializable, T extends Serializable> extends HibernateDaoSupport implements InitializingBean {
private Logger logger = LoggerFactory.getLogger(HibernateDAO.class);
public static final int MAX_RETRY = 5;

protected Class<T> domainClass = getDomainClass();

public Object retryRun(RetriableTask task) {
Exception exception = null;
for (int i = 0; i < MAX_RETRY; i++) {
try {
return task.action();
} catch (Exception e) {
exception = e;
boolean deadlock = false;
for (StackTraceElement element: e.getStackTrace()) {
if (element.toString().toLowerCase().contains("deadlock")) {
deadlock = true;
}
}
if (e.getMessage() != null && deadlock) {
try {
Thread.sleep(8000);
} catch (Exception ex) {}
logger.warn("Deadlock detected. Retrying " + i + "/" + MAX_RETRY);
} else {
throw new RuntimeException(e);
}
}
}

throw new RuntimeException(exception);
}

public T get(final K id) {
return (T)retryRun(new RetriableTask() {

public Object action() throws Exception {
return (T)getCachedHibernateTemplate().get(domainClass, id);
}
});
}

public Collection<T> getAll() {
return (Collection<T>)retryRun(new RetriableTask() {

public Object action() throws Exception {
return getCachedHibernateTemplate().loadAll(domainClass);
}
});
}

public K save(final T entity) {
return (K)retryRun(new RetriableTask() {

public Object action() throws Exception {
return (K)(getCachedHibernateTemplate().save(entity));
}
});
}

public void saveOrUpdate(final T entity) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().saveOrUpdate(entity);
getCachedHibernateTemplate().flush();
return null;
}
});
}

public void update(final T entity) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().update(entity);
getCachedHibernateTemplate().flush();
return null;
}
});
}

public void delete(final T entity) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().delete(entity);
return null;
}
});
}

public void saveOrUpdateAll(final Collection<T> list) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().saveOrUpdateAll(list);
getCachedHibernateTemplate().flush();
return null;
}
});
}

public void deleteById(final K id) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
T obj = get(id);
getCachedHibernateTemplate().delete(obj);
getCachedHibernateTemplate().flush();
return null;
}
});
}

protected HibernateTemplate getCachedHibernateTemplate() {
HibernateTemplate template = getHibernateTemplate();
template.setCacheQueries(true);
return template;
}

protected Class getDomainClass() {
if (domainClass == null) {
ParameterizedType thisType = (ParameterizedType) getClass().getGenericSuperclass();

// get T, so the 2nd class
domainClass = (Class) thisType.getActualTypeArguments()[1];
}
return domainClass;
}

public List find(final String query) {
return (List)retryRun(new RetriableTask() {
public Object action() throws Exception {
return getCachedHibernateTemplate().find(query);
}
});
}

public List find(final String query, final Object[] params) {
return (List)retryRun(new RetriableTask() {
public Object action() throws Exception {
return getCachedHibernateTemplate().find(query, params);
}
});
}

public T findSingle(final String query, final Object[] params) {
return (T)retryRun(new RetriableTask() {
public Object action() throws Exception {
List<T> list = getCachedHibernateTemplate().find(query, params);
if (list.isEmpty()) {
return null;
}

return list.get(0);
}
});
}

public void bulkUpdate(final String query, final Object[] params) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().bulkUpdate(query, params);
getCachedHibernateTemplate().flush();
return null;
}
});
}

public void bulkUpdate(final String query) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().bulkUpdate(query);
getCachedHibernateTemplate().flush();
return null;
}
});
}

public void saveAll(final Collection<T> entities) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
_saveAll(entities);
return null;
}
});
}

private void _saveAll(final Collection<T> entities) {
getHibernateTemplate().execute(new HibernateCallback() {

public Object doInHibernate(Session session)
throws HibernateException, SQLException {
try {
// consider packets of 1000 max
int counter = 0;
session.beginTransaction();
for (T entity: entities) {
session.save(entity);
}
session.getTransaction().commit();
session.flush();
session.clear();
} catch (Exception e) {
session.getTransaction().rollback();
e.printStackTrace();
}
return null;
}

});
}

public boolean updateAll(final Collection<T> entities) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
return _updateAll(entities);

}
});
return true;
}

private boolean _updateAll(final Collection<T> entities) {
getHibernateTemplate().execute(new HibernateCallback() {

public Object doInHibernate(Session session)
throws HibernateException, SQLException {
try {
session.beginTransaction();
for (T entity: entities) {
session.update(entity);
}
session.getTransaction().commit();
session.flush();
session.clear();
} catch (Exception e) {
session.getTransaction().rollback();
e.printStackTrace();
return false;
}
return true;
}

});
return true;
}

public void deleteAll(final Collection<T> entities) {
retryRun(new RetriableTask() {
public Object action() throws Exception {
_deleteAll(entities);
return null;
}
});
}

private void _deleteAll(final Collection<T> entities) {
getHibernateTemplate().execute(new HibernateCallback() {

public Object doInHibernate(Session session)
throws HibernateException, SQLException {
try {
session.beginTransaction();
for (T entity: entities) {
session.delete(entity);
}
session.getTransaction().commit();
session.flush();
session.clear();
} catch (Exception e) {
session.getTransaction().rollback();
e.printStackTrace();
}
return null;
}

});
}

public void flush() {
retryRun(new RetriableTask() {
public Object action() throws Exception {
getCachedHibernateTemplate().flush();
return null;
}
});
}

public interface RetriableTask {
public Object action() throws Exception;
}
}

Monday, 1 August 2016

import java.util.Properties;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;

import com.demo.pojo.Products;
import com.demo.pojo.User;

public class HibernateConnection {

public static SessionFactory sessionFactory;

public static SessionFactory doHibernateConnection(){
Properties database = new Properties();
database.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
database.setProperty("hibernate.connection.username", "root");
database.setProperty("hibernate.connection.password", "");
database.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/spring");
database.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");

Configuration cfg = new Configuration()
.setProperties(database)
.addPackage("com.demo.pojo")
.addAnnotatedClass(User.class)
.addAnnotatedClass(Products.class);

StandardServiceRegistryBuilder ssrb = new StandardServiceRegistryBuilder().applySettings(cfg.getProperties());

sessionFactory = cfg.buildSessionFactory(ssrb.build());

return sessionFactory;

}

}

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<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">

<groupId>HibernateStuff</groupId>

<artifactId>HibernateStuff</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>Hibernate Stuff</name>

<description>Hibernate Stuff</description>

<build>

<artifactId>maven-compiler-plugin</artifactId>

</configuration>

</plugin>

<artifactId>maven-war-plugin</artifactId>

<warSourceDirectory>WebContent</warSourceDirectory>

<failOnMissingWebXml>false</failOnMissingWebXml>

</configuration>

</plugin>

</plugins>

</build>

<groupId>org.springframework</groupId>

<artifactId>spring-beans</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-context</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-core</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-webmvc</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-web</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<groupId>javax.servlet</groupId>

</dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>

<groupId>commons-fileupload</groupId>

<artifactId>commons-fileupload</artifactId>

</dependency>

<groupId>javax.validation</groupId>

<artifactId>validation-api</artifactId>

<version>1.1.0.Final</version>

</dependency>