p namespace

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1 (p namespace) | 2 (c namespace)

The main purpose of p namespace is to remove the long <property> tags  from xml configuration file. You can think p namespace as a kind of shortcut notation of <property> tags.

Consider following example:

Student.java

package di.pnamespace;

public class Student {
    private String name;
    private int age;
    private Course course;

      // setters and getters   

    public void displayInfo(){
       
        System.out.println("Student Name : "+name);
        System.out.println("Student Age : "+ age);
        System.out.println("Course name : "+course.getCourseName());
    }
}

Course.java

package di.pnamespace;

public class Course {

    String courseName;
   
    public void setCourseName(String name){
        this.courseName = name;
       
    }
    public String getCourseName(){
        return courseName;
       
    }
   
}

MainApp.java

package di.pnamespace;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;


public class MainApp{
public static void main(String args[]){
   
    ApplicationContext appContext = new ClassPathXmlApplicationContext("resources/ApplicationContext.xml");
    Student stud = (Student)appContext.getBean("student");
    stud.displayInfo();
 }
}

ApplicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="https://www.springframework.org/schema/beans"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xmlns:p="https://www.springframework.org/schema/p"
xsi:schemaLocation="https://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<bean id="student" class="di.pnamespace.Student">
<property name="name" value="abc"/>
<property name="age" value="30"/>
<property name="course" ref="course1"/>
</bean>

<bean id="course1" class="di.pnamespace.Course">
<property name="courseName" value="computers"/>
</bean>
</beans>

In the above program dependencies of Student and Course class have been injected using <property> tags.

Now the same program using p namespace is (you only need to change ApplicationContext.xml, other classes remain same):

ApplicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="https://www.springframework.org/schema/beans"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xmlns:p="https://www.springframework.org/schema/p"
xsi:schemaLocation="https://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<bean id="student" class="di.pnamespace.Student" p:name="abc" p:age="31" p:course-ref="course1"/>
<bean id="course1" class="di.pnamespace.Course" p:courseName="computers"/>
</beans>

In the above program we are using p namespace to inject the dependencies of Student and Course classes.

For example,

p:age="31" is substitute of:
<property  name="age" value="31">

Note how we are injecting reference to other bean as a value of property -course of Student class, using p namespace:

p:course-ref="course1"
is a substitute of
<property name="course" ref="course1">

Note the -ref at the end of p:course-ref="course1". -ref means this property would accept a reference to other bean as its value.

Also note that unlike <property> tags, p namespace are not separate tags but they are the part of <bean> tag

For p namepsace to work you have to add its schema URI https://www.springframework.org/schema/p in above xml file.

1 (p namespace) | 2 (c namespace)

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