Operators in spEL

 

 
The various operators that are most frequently used in this context are :-

• Relational operators

  1. equal (==)
  2. not equal (!=)
  3. less than (<)
  4. less than or equal (<=)
  5. greater than (>)
  6. greater than or equal (>=)

• Logical operators

  1. And(&&)
  2. Or(||)
  3. not (!).

• Mathematical operators

  1. addition (+)
  2. Subtraction (-)
  3. Multiplication (*)
  6. division (/)
  7. modulus (%)
  8. exponential power (^).

• Ternary operator

  1. if-then-else (<condn> ? <stmt1 if true> : <Stmt2 if false>)
     .

Step 1 : Create a sample POJO

 
File : Operators.java

package com.simpleCodeStuffs.spEL;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("operators")
public class Operators {

	@Value("#{1==1}")
	private boolean equals;

	public boolean isEquals() {
		return equals;
	}

	public void setEquals(boolean equals) {
		this.equals = equals;
	}
}

 

Step 2 : Create the main class

 
File : MainClass.java

package com.simpleCodeStuffs.spEL;

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

public class MainClass {

	public static void main(String[] args) {

		ApplicationContext context =
		     new ClassPathXmlApplicationContext("elBeans.xml");
		Operators op = (Operators) context.getBean("operators");
		System.out.println("equals" + op.isEquals());
	}
}

 

Step 3 : Enable automatic component scanning in elBeans.xml

 
File : elBeans.xml

 

Step 4 : Run the program. The output is

 

 

Step 5 : Other operators and the functionalities

 

    @Value("#{1 != 5}") //true
	private boolean NotEqual;
 
	@Value("#{1 < 1}") //false
	private boolean LessThan;
 
	@Value("#{1 <= 1}") //true
	private boolean LessThanOrEqual;
 
	@Value("#{1 > 1}") //false
	private boolean GreaterThan;
 
	@Value("#{1 >= 1}") //true
	private boolean GreaterThanOrEqual;
 
	/*
	 * Logical operators , numberBean.no == 999
	 * @Value("#{numberBean.no == 999 and numberBean.no < 900}")
	 * can be used in case 'numberBean' is another bean.
	 */
 
	@Value("#{999 == 999 and 999 < 900}") //false
	private boolean And;
 
	@Value("#{999 == 999 or 999 < 900}") //true
	private boolean Or;
 
	@Value("#{!(999 == 999)}") //false
	private boolean Not;
 
	//Mathematical operators
 
	@Value("#{1 + 1}") //2.0
	private double testAdd;
 
	@Value("#{'1' + '@' + '1'}") //1@1
	private String AddString;
 
	@Value("#{1 - 1}") //0.0
	private double Subtraction;
 
	@Value("#{1 * 1}") //1.0
	private double Multiplication;
 
	@Value("#{10 / 2}") //5.0
	private double Division;
 
	@Value("#{10 % 10}") //0.0
	private double Modulus ;
 
	@Value("#{2 ^ 2}") //4.0
	private double ExponentialPower;

 

//Ternary operator
@Value("#{99!=0?'expresion holds true':'expression is false'}")
	private String name;
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

 
File : Operators.java
 

package com.simpleCodeStuffs.spEL;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("operators")
public class Operators {

	@Value("#{99!=0?'expresion holds true':'expression is false'}")
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

 
File : MainClass.java
 

package com.simpleCodeStuffs.spEL;

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

public class MainClass {

	public static void main(String[] args) {

		ApplicationContext context =
			 new ClassPathXmlApplicationContext("elBeans.xml");
		Operators op = (Operators) context.getBean("operators");
		System.out.println(op.getName());
	}
}

 

The output is -