Does Spring Expression Language support IN operator? - spring-el

Question

Does Spring Expression Language support IN operator? Similar to SQL IN clause.
public class Security {
private secTyp1;
public Security (String aSecTyp1) {
secTyp1 = aSecTyp1;
}
}
Security security = new Security("BOND");
StandardEvaluationContext context = new StandardEvaluationContext(security);
ExpressionParser parser = new SpelExpressionParser();
// This should return true
boolean result = parser.parseExpression("secTyp1 **IN** {'BOND','SWPI'}").getValue(context, Boolean.class);
// This should return false
result = parser.parseExpression("secTyp1 **IN** {'FUT','SWPI'}").getValue(context, Boolean.class);
I get the following exception
org.springframework.expression.spel.SpelParseException: EL1041E:(pos 8): After parsing a valid expression, there is still more data in the expression: 'IN'
at org.springframework.expression.spel.standard.InternalSpelExpressionParser.doParseExpression(InternalSpelExpressionParser.java:118)
at org.springframework.expression.spel.standard.SpelExpressionParser.doParseExpression(SpelExpressionParser.java:56)
at org.springframework.expression.spel.standard.SpelExpressionParser.doParseExpression(SpelExpressionParser.java:1)
at org.springframework.expression.common.TemplateAwareExpressionParser.parseExpression(TemplateAwareExpressionParser.java:66)
at org.springframework.expression.common.TemplateAwareExpressionParser.parseExpression(TemplateAwareExpressionParser.java:56)
at com.rules.AssignableSecurityRule.evaluateInCondition(AssignableSecurityRule.java:48)
at com.rules.AssignableSecurityRuleTest.testINCondition(AssignableSecurityRuleTest.java:43)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Answer 1

It does not support the IN operator because you do not need it. You can use the Method invokation feature instead.
So, invoking .contains(..) on a list will do what you want.
You can try those two solutions
#Test
public void solutionOneTest() {
final Security security = new Security("BOND");
final EvaluationContext context = new StandardEvaluationContext(security);
Boolean contains = PARSER.parseExpression("{'BOND','SWPI'}.contains(#root.secTyp1)").getValue(context, Boolean.class);
Assert.assertTrue(contains);
contains = PARSER.parseExpression("{'FUT','SWPI'}.contains(#root.secTyp1)").getValue(context, Boolean.class);
Assert.assertFalse(contains);
}
#Test
public void solutionTwoTest() {
final Security security = new Security("BOND");
final EvaluationContext context = new StandardEvaluationContext();
context.setVariable("sec", security);
Boolean contains = PARSER.parseExpression("{'BOND','SWPI'}.contains(#sec.secTyp1)").getValue(context, Boolean.class);
Assert.assertTrue(contains);
contains = PARSER.parseExpression("{'FUT','SWPI'}.contains(#sec.secTyp1)").getValue(context, Boolean.class);
Assert.assertFalse(contains);
}

Answer 2

In addition to calling methods directly as in micfra's answer, SpEL also supports some pretty powerful collection filtering expressions as well. Collection Selection allows you to filter out a sublist of matching values, when you could then test for size:
!{'BOND','SWPI'}.?[#this == 'BOND'].empty
Where this is really handy is filtering lists of complex objects:
!securities.?[secTyp1 == 'BOND'].empty