BE THE CODER > Spring > Expression Language

The Spring Expression Language (SpEL) is a simple and powerful expression language which helps to query and manipulate objects at runtime. The following example shows using this variable (#this) for the selection of odd and even numbers. Refer Collection Selection tutorials to know more on selection operator.

File Name :	com/bethecoder/tutorials/spring3/tests/spel/ThisVariableTest.java
Author :	Sudhakar KV
Email :	[email protected]


package com.bethecoder.tutorials.spring3.tests.spel;



import java.util.Arrays;

import java.util.List;



import org.springframework.expression.ExpressionParser;

import org.springframework.expression.spel.standard.SpelExpressionParser;

import org.springframework.expression.spel.support.StandardEvaluationContext;



public class ThisVariableTest {



  /**

   * @param args

   */

  public static void main(String[] args) {



    List<Integer> nums = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8);

    System.out.println("Numbers : " + nums);

    

    ExpressionParser parser = new SpelExpressionParser();

    StandardEvaluationContext stdContext = new StandardEvaluationContext();

    stdContext.setVariable("nums", nums);



    //Filter Even numbers from the list (using selection ?{...})

    List<Integer> evenNums = 

      (List<Integer>) parser.parseExpression("#nums.?[#this % 2 == 0]").getValue(stdContext);

    System.out.println("Even Numbers : " + evenNums);



    //Filter Odd numbers from the list (using selection ?{...})

    List<Integer> oddNums = 

      (List<Integer>) parser.parseExpression("#nums.?[#this % 2 == 1]").getValue(stdContext);

    System.out.println("Odd Numbers : " + oddNums);

    

  }



}

This Variable