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 selection operator (?[selectionExpression]). It filters the collection and returns a new collection containing a subset of the original elements. The selection criteria is evaluated against each individual element in the list.

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


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



import java.util.ArrayList;

import java.util.List;



import org.springframework.expression.ExpressionParser;

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

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



import com.bethecoder.tutorials.spring3.basic.Employee;



public class ListSelectionTest {



  /**

   * @param args

   */

  public static void main(String[] args) {



    StandardEvaluationContext stdContext = new StandardEvaluationContext();

    List<Employee> employees = new ArrayList<Employee>();

    employees.add(new Employee(1, "ONE", 1111));

    employees.add(new Employee(2, "TWO", 2222));

    employees.add(new Employee(3, "THREE", 3333));

    employees.add(new Employee(4, "FOUR", 4444));

    employees.add(new Employee(5, "FIVE", 5555));

    employees.add(new Employee(6, "SIX", 6666));

    

    stdContext.setVariable("emps", employees);

    

    /**

     * Employees having salary greater than 4000

     */

    ExpressionParser parser = new SpelExpressionParser();

    List<Employee> subSet = (List<Employee>) parser.parseExpression(

        "#emps.?[salary > 4000]").getValue(stdContext);

    System.out.println(subSet); 



    /**

     * Employees having salary less than 4000

     */

    subSet = (List<Employee>) parser.parseExpression(

        "#emps.?[salary < 4000]").getValue(stdContext);

    System.out.println(subSet);

  }



}

List Selection