Understanding Propagation value for @Transactional in Spring

MANDATORY
Support a current transaction, throw an exception if none exists.
NESTED
Execute within a nested transaction if a current transaction exists, behave like PROPAGATION_REQUIRED else.
NEVER
Execute non-transactionally, throw an exception if a transaction exists.
NOT_SUPPORTED
Execute non-transactionally, suspend the current transaction if one exists.
REQUIRED
Support a current transaction, create a new one if none exists.
REQUIRES_NEW
Create a new transaction, suspend the current transaction if one exists.
SUPPORTS
Support a current transaction, execute non-transactionally if none exists.

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Posted in Hibernate, Spring | Leave a comment

Creating custom function on JavaScript String startsWith and endsWith


if (typeof String.prototype.startsWith != 'function') {
                String.prototype.startsWith = function(str) {
                    return this.slice(0, str.length) == str;
                };
}

if (typeof String.prototype.endsWith != 'function') {
                String.prototype.endsWith = function(str) {
                    return this.slice(-str.length) == str;
                };
}
alert('mankind'.startsWith('man'));
alert('mankind'.endsWith('kind'));

Posted in Javascript, JQuery | Leave a comment

Hibernate Inheritance: Table Per Concrete Class

package taher.javahunter.hibernate;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;
 
 
@Entity
@Table(name = "PERSON")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Person {
 
    @Id
    @Column(name = "PERSON_ID")
    private Long personId;
     
    @Column(name = "FIRSTNAME")
    private String firstname;
     
    @Column(name = "LASTNAME")
    private String lastname;
     
    public Person() {
     
    }
    public Person(String firstname, String lastname) {
        this.firstname = firstname;
        this.lastname = lastname;
    }
    // Getter and Setter methods, 
}
package taher.javahunter.hibernate;
 
import java.util.Date;
 
import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
 
@Entity
@Table(name="EMPLOYEE")
@AttributeOverrides({
    @AttributeOverride(name="firstname", column=@Column(name="FIRSTNAME")),
    @AttributeOverride(name="lastname", column=@Column(name="LASTNAME"))
})
public class Employee extends Person {
 
    @Column(name="joining_date")
    private Date joiningDate;
     
    @Column(name="department_name")
    private String departmentName;
 
    public Employee() {
    }
     
    public Employee(String firstname, String lastname, String departmentName, Date joiningDate) {
         
        super(firstname, lastname);
         
        this.departmentName = departmentName;
        this.joiningDate = joiningDate;
    }
     
    // Getter and Setter methods, 
}
package taher.javahunter.hibernate;
 
import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
 
@Entity
@Table(name="OWNER")
@AttributeOverrides({
    @AttributeOverride(name="firstname", column=@Column(name="FIRSTNAME")),
    @AttributeOverride(name="lastname", column=@Column(name="LASTNAME"))
})
public class Owner extends Person {
 
    @Column(name="stocks")
    private Long stocks;
     
    @Column(name="partnership_stake")
    private Long partnershipStake;
 
    public Owner() {
    }
     
    public Owner(String firstname, String lastname, Long stocks, Long partnershipStake) {
         
        super(firstname, lastname);
         
        this.stocks = stocks;
        this.partnershipStake = partnershipStake;
    }
 
    // Getter and Setter methods, 
}
Output :

Hibernate: insert into PERSON (FIRSTNAME, LASTNAME, PERSON_ID) values (?, ?, ?)
Hibernate: insert into EMPLOYEE (FIRSTNAME, LASTNAME, department_name, joining_date, PERSON_ID) values (?, ?, ?, ?, ?)
Hibernate: insert into OWNER (FIRSTNAME, LASTNAME, partnership_stake, stocks, PERSON_ID) values (?, ?, ?, ?, ?)

Posted in Hibernate | Leave a comment

Hibernate Inheritance: Table Per Subclass

CREATE TABLE `person` (
    `person_id` BIGINT(20) NOT NULL AUTO_INCREMENT,
    `firstname` VARCHAR(50) NOT NULL DEFAULT '0',
    `lastname` VARCHAR(50) NOT NULL DEFAULT '0',
    PRIMARY KEY (`person_id`)
)
 
CREATE TABLE `employee` (
    `person_id` BIGINT(10) NOT NULL,
    `joining_date` DATE NULL DEFAULT NULL,
    `department_name` VARCHAR(50) NULL DEFAULT NULL,
    PRIMARY KEY (`person_id`),
    CONSTRAINT `FK_PERSON` FOREIGN KEY (`person_id`) REFERENCES `person` (`person_id`)
)
 
CREATE TABLE `owner` (
    `person_id` BIGINT(20) NOT NULL DEFAULT '0',
    `stocks` BIGINT(11) NULL DEFAULT NULL,
    `partnership_stake` BIGINT(11) NULL DEFAULT NULL,
    PRIMARY KEY (`person_id`),
    CONSTRAINT `FK_PERSON2` FOREIGN KEY (`person_id`) REFERENCES `person` (`person_id`)
)
package taher.javahunter.hibernate;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;
 
 
@Entity
@Table(name = "PERSON")
@Inheritance(strategy=InheritanceType.JOINED)
public class Person {
 
    @Id
    @GeneratedValue
    @Column(name = "PERSON_ID")
    private Long personId;
     
    @Column(name = "FIRSTNAME")
    private String firstname;
     
    @Column(name = "LASTNAME")
    private String lastname;
     
    public Person() {
     
    }
    public Person(String firstname, String lastname) {
        this.firstname = firstname;
        this.lastname = lastname;
    }
 
    // Getter and Setter methods, 
}
package taher.javahunter.hibernate;
 
import java.util.Date;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;
 
@Entity
@Table(name="EMPLOYEE")
@PrimaryKeyJoinColumn(name="PERSON_ID")
public class Employee extends Person {
 
    @Column(name="joining_date")
    private Date joiningDate;
     
    @Column(name="department_name")
    private String departmentName;
 
    public Employee() {
    }
     
    public Employee(String firstname, String lastname, String departmentName, Date joiningDate) {
         
        super(firstname, lastname);
         
        this.departmentName = departmentName;
        this.joiningDate = joiningDate;
    }
 
    // Getter and Setter methods, 
}
package taher.javahunter.hibernate;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;
 
@Entity
@Table(name="OWNER")
@PrimaryKeyJoinColumn(name="PERSON_ID")
public class Owner extends Person {
 
    @Column(name="stocks")
    private Long stocks;
     
    @Column(name="partnership_stake")
    private Long partnershipStake;
 
    public Owner() {
    }
     
    public Owner(String firstname, String lastname, Long stocks, Long partnershipStake) {
         
        super(firstname, lastname);
         
        this.stocks = stocks;
        this.partnershipStake = partnershipStake;
    }
 
    // Getter and Setter methods, 
}
Output :

Hibernate: insert into PERSON (firstname, lastname) values (?, ?)
Hibernate: insert into PERSON (firstname, lastname) values (?, ?)
Hibernate: insert into Employee (department_name, joining_date, person_id) values (?, ?, ?)
Hibernate: insert into PERSON (firstname, lastname) values (?, ?)
Hibernate: insert into Owner (stocks, partnership_stake, person_id) values (?, ?, ?)

Posted in Hibernate | Leave a comment

Hibernate Inheritance: Table Per Class Hierarchy

* class Person
– firstname
– lastname

* class Employee
– joining_date
– department_name

package taher.javahunter.hibernate;
 
import javax.persistence.Column;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;
 
 
@Entity
@Table(name = "PERSON")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(
    name="discriminator",
    discriminatorType=DiscriminatorType.STRING
)
@DiscriminatorValue(value="P")
public class Person {
 
    @Id
    @GeneratedValue
    @Column(name = "PERSON_ID")
    private Long personId;
     
    @Column(name = "FIRSTNAME")
    private String firstname;
     
    @Column(name = "LASTNAME")
    private String lastname;
     
    // Constructors and Getter/Setter methods, 
}
package taher.javahunter.hibernate;
 
import java.util.Date;
 
import javax.persistence.Column;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.Table;
 
@Entity
@Table(name="PERSON")
@DiscriminatorValue("E")
public class Employee extends Person {
 
    @Column(name="joining_date")
    private Date joiningDate;
     
    @Column(name="department_name")
    private String departmentName;
 
    // Constructors and Getter/Setter methods, 
}
Output :

Hibernate: insert into EMPLOYEE (FIRSTNAME, LASTNAME, discriminator) values (?, ?, ‘P’)
Hibernate: insert into EMPLOYEE (FIRSTNAME, LASTNAME, department_name, joining_date, discriminator) values (?, ?, ?, ?, ‘E’)

Posted in Hibernate | Leave a comment

Spring AOP

Spring AOP (Aspect-oriented programming) framework is used to modularize cross-cutting concerns in aspects. Put it simple, it’s just an interceptor to intercept some processes, for example, when a method is execute, Spring AOP can hijack the executing method, and add extra functionality before or after the method execution.

In Spring AOP, 4 type of advices are supported :

Before advice – Run before the method execution
After returning advice – Run after the method returns a result
After throwing advice – Run after the method throws an exception
Around advice – Run around the method execution, combine all three advices above.
Following example show you how Spring AOP advice works.

Simple Spring example
Create a simple customer service class with few print methods for demonstration later.

package com.javahunter.customer.services;
 
public class CustomerService {
	private String name;
	private String url;
 
	public void setName(String name) {
		this.name = name;
	}
 
	public void setUrl(String url) {
		this.url = url;
	}
 
	public void printName() {
		System.out.println("Customer name : " + this.name);
	}
 
	public void printURL() {
		System.out.println("Customer website : " + this.url);
	}
 
	public void printThrowException() {
		throw new IllegalArgumentException();
	}
 
}

File : Spring-Customer.xml – A bean configuration file

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
	<bean id="customerService" class="com.javahunter.customer.services.CustomerService">
		<property name="name" value="Taher Java Hunter" />
		<property name="url" value="https://javahunter.wordpress.com" />
	</bean>
 
</beans>

Run it

package com.javahunter.common;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.javahunter.customer.services.CustomerService;
 
public class App {
	public static void main(String[] args) {
		ApplicationContext appContext = new ClassPathXmlApplicationContext(
				new String[] { "Spring-Customer.xml" });
 
		CustomerService cust = (CustomerService) appContext.getBean("customerService");
 
		System.out.println("*************************");
		cust.printName();
		System.out.println("*************************");
		cust.printURL();
		System.out.println("*************************");
		try {
			cust.printThrowException();
		} catch (Exception e) {
 
		}
 
	}
}
Output :

*************************
Customer name : Taher Java Hunter
*************************
Customer website : https://javahunter.wordpress.com
*************************

A simple Spring project to DI a bean and output some Strings.

Spring AOP Advices
Now, attach Spring AOP advices to above customer service.

1. Before advice
It will execute before the method execution. Create a class which implements MethodBeforeAdvice interface.

package com.javahunter.aop;
 
import java.lang.reflect.Method;
import org.springframework.aop.MethodBeforeAdvice;
 
public class HijackBeforeMethod implements MethodBeforeAdvice
{
	@Override
	public void before(Method method, Object[] args, Object target)
		throws Throwable {
	        System.out.println("HijackBeforeMethod : Before method hijacked!");
	}
}

In bean configuration file (Spring-Customer.xml), create a bean for HijackBeforeMethod class , and a new proxy object named ‘customerServiceProxy‘.

‘target’ – Define which bean you want to hijack.
‘interceptorNames’ – Define which class (advice) you want to apply on this proxy /target object.

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
	<bean id="customerService" class="com.javahunter.customer.services.CustomerService">
		<property name="name" value="Taher Java Hunter" />
		<property name="url" value="https://javahunter.wordpress.com" />
	</bean>
 
	<bean id="hijackBeforeMethodBean" class="com.javahunter.aop.HijackBeforeMethod" />
 
	<bean id="customerServiceProxy" 
                 class="org.springframework.aop.framework.ProxyFactoryBean">
 
		<property name="target" ref="customerService" />
 
		<property name="interceptorNames">
			<list>
				<value>hijackBeforeMethodBean</value>
			</list>
		</property>
	</bean>
</beans>

Note
To use Spring proxy, you need to add CGLIB2 library. Add below in Maven pom.xml file.

	<dependency>
		<groupId>cglib</groupId>
		<artifactId>cglib</artifactId>
		<version>2.2.2</version>
	</dependency>	
	

Run it again, now you get the new customerServiceProxybean instead of the original customerService bean.

package com.javahunter.common;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.javahunter.customer.services.CustomerService;
 
public class App {
	public static void main(String[] args) {
		ApplicationContext appContext = new ClassPathXmlApplicationContext(
				new String[] { "Spring-Customer.xml" });
 
		CustomerService cust = 
                                (CustomerService) appContext.getBean("customerServiceProxy");
 
		System.out.println("*************************");
		cust.printName();
		System.out.println("*************************");
		cust.printURL();
		System.out.println("*************************");
		try {
			cust.printThrowException();
		} catch (Exception e) {
 
		}
 
	}
}
Output :

*************************
HijackBeforeMethod : Before method hijacked!
Customer name : Taher Java Hunter
*************************
HijackBeforeMethod : Before method hijacked!
Customer website : https://javahunter.wordpress.com
*************************
HijackBeforeMethod : Before method hijacked!

It will run the HijackBeforeMethod’s before() method, before every customerService’s methods are execute.

2. After returning advice
It will execute after the method is returned a result. Create a class which implements AfterReturningAdvice interface.

package com.javahunter.aop;
 
import java.lang.reflect.Method;
import org.springframework.aop.AfterReturningAdvice;
 
public class HijackAfterMethod implements AfterReturningAdvice
{
	@Override
	public void afterReturning(Object returnValue, Method method,
		Object[] args, Object target) throws Throwable {
	        System.out.println("HijackAfterMethod : After method hijacked!");
	}
}

Bean configuration file

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
	<bean id="customerService" class="com.javahunter.customer.services.CustomerService">
		<property name="name" value="Taher Java Hunter" />
		<property name="url" value="https://javahunter.wordpress.com" />
	</bean>
 
	<bean id="hijackAfterMethodBean" class="com.javahunter.aop.HijackAfterMethod" />
 
	<bean id="customerServiceProxy" 
                class="org.springframework.aop.framework.ProxyFactoryBean">
 
		<property name="target" ref="customerService" />
 
		<property name="interceptorNames">
			<list>
				<value>hijackAfterMethodBean</value>
			</list>
		</property>
	</bean>
</beans>

Run it again,

Output :

*************************
Customer name : Taher Java Hunter
HijackAfterMethod : After method hijacked!
*************************
Customer website : https://javahunter.wordpress.com
HijackAfterMethod : After method hijacked!
*************************

It will run the HijackAfterMethod’s afterReturning() method, after every customerService’s methods that are returned result.

3. After throwing advice
It will execute after the method throws an exception. Create a class which implements ThrowsAdvice interface, and create a afterThrowing method to hijack the IllegalArgumentException exception.

package com.javahunter.aop;
 
import org.springframework.aop.ThrowsAdvice;
 
public class HijackThrowException implements ThrowsAdvice {
	public void afterThrowing(IllegalArgumentException e) throws Throwable {
		System.out.println("HijackThrowException : Throw exception hijacked!");
	}
}

Bean configuration file

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
	<bean id="customerService" class="com.javahunter.customer.services.CustomerService">
		<property name="name" value="Taher Java Hunter" />
		<property name="url" value="https://javahunter.wordpress.com" />
	</bean>
 
	<bean id="hijackThrowExceptionBean" class="com.javahunter.aop.HijackThrowException" />
 
	<bean id="customerServiceProxy" 
                 class="org.springframework.aop.framework.ProxyFactoryBean">
 
		<property name="target" ref="customerService" />
 
		<property name="interceptorNames">
			<list>
				<value>hijackThrowExceptionBean</value>
			</list>
		</property>
	</bean>
</beans>

Run it again,

Output :

*************************
Customer name : Taher Java Hunter
*************************
Customer website : https://javahunter.wordpress.com
*************************
HijackThrowException : Throw exception hijacked!

It will run the HijackThrowException’s afterThrowing() method, if customerService’s methods throw an exception.

4. Around advice
It combines all three advices above, and execute during method execution. Create a class which implements MethodInterceptor interface. You have to call the “methodInvocation.proceed();” to proceed on the original method execution, else the original method will not execute.

package com.javahunter.aop;
 
import java.util.Arrays;
 
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
 
public class HijackAroundMethod implements MethodInterceptor {
	@Override
	public Object invoke(MethodInvocation methodInvocation) throws Throwable {
 
		System.out.println("Method name : "
				+ methodInvocation.getMethod().getName());
		System.out.println("Method arguments : "
				+ Arrays.toString(methodInvocation.getArguments()));
 
		// same with MethodBeforeAdvice
		System.out.println("HijackAroundMethod : Before method hijacked!");
 
		try {
			// proceed to original method call
			Object result = methodInvocation.proceed();
 
			// same with AfterReturningAdvice
			System.out.println("HijackAroundMethod : Before after hijacked!");
 
			return result;
 
		} catch (IllegalArgumentException e) {
			// same with ThrowsAdvice
			System.out.println("HijackAroundMethod : Throw exception hijacked!");
			throw e;
		}
	}
}

Bean configuration file

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
	<bean id="customerService" class="com.javahunter.customer.services.CustomerService">
		<property name="name" value="Taher Java Hunter" />
		<property name="url" value="https://javahunter.wordpress.com" />
	</bean>
 
	<bean id="hijackAroundMethodBean" class="com.javahunter.aop.HijackAroundMethod" />
 
	<bean id="customerServiceProxy" 
                class="org.springframework.aop.framework.ProxyFactoryBean">
 
		<property name="target" ref="customerService" />
 
		<property name="interceptorNames">
			<list>
				<value>hijackAroundMethodBean</value>
			</list>
		</property>
	</bean>
</beans>

Run it again,

Output :

*************************
Method name : printName
Method arguments : []
HijackAroundMethod : Before method hijacked!
Customer name : Taher Java Hunter
HijackAroundMethod : Before after hijacked!
*************************
Method name : printURL
Method arguments : []
HijackAroundMethod : Before method hijacked!
Customer website : https://javahunter.wordpress.com
HijackAroundMethod : Before after hijacked!
*************************
Method name : printThrowException
Method arguments : []
HijackAroundMethod : Before method hijacked!
HijackAroundMethod : Throw exception hijacked!

It will run the HijackAroundMethod’s invoke()method, after every customerService’s method execution.

Conclusion
Most of the Spring developers are just implements the ‘Around advice ‘, since it can apply all the advice type, but a better practice should choose the most suitable advice type to satisfy the requirements.

Posted in Spring | Tagged , | Leave a comment

Check String is Numeric in Java

public static  boolean isNumeric(String nums){
        List<Integer> numbers = Arrays.asList(new Integer[]{46,48,49,50,51,52,53,54,55,56,57});
        int numCnt=0;
        char[] c = nums.toCharArray();
        for (int d : c) {
            if(numbers.contains(d)){
                numCnt++;                
            }
        }
        return numCnt == c.length;
    }
Posted in Core JAVA, Scripting in JAVA | Leave a comment