Conditional operator less than apache camel simple

Question

I need help to create a rule in simple apache camel where I can validate if an integer value is less than or equal, however, I can't make it work, as below:

${in.header.name} == null and ${in.header.id} <= 50

through the documentation I tested the function above and it does not work

Answer 1

Instead of and you should use && you might also want to drop out the in part from the ${in.header.name} and use ${header.name} instead.

• Using and / or in Simple language.
• Variables

I also recommend using Predicates with Java-DSL over simple language strings. They're less prone to typos than simple-language strings and one can build fairly complex predicates using PredicateBuilder.

Example test using simple-lang and predicates:

package org.example;

import java.util.HashMap;

import org.apache.camel.Predicate;
import org.apache.camel.RoutesBuilder;
import org.apache.camel.builder.PredicateBuilder;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.component.mock.MockEndpoint;
import org.apache.camel.test.junit5.CamelTestSupport;
import org.junit.jupiter.api.Test;

public class ComparisonTest extends CamelTestSupport {
    
    @Test
    public void simpleComparisonSixIsGreater() throws Exception  {

        MockEndpoint isGreaterMockEndpoint = getMockEndpoint("mock:isGreater");
        isGreaterMockEndpoint.expectedMessageCount(1);

        HashMap<String, Object> headers = createHashmapForNameAndIdHeaders(null, 6);
        template.sendBodyAndHeaders("direct:simpleComparison", null, headers);

        isGreaterMockEndpoint.assertIsSatisfied();
    }

    @Test
    public void simpleComparisonThreeIsLowerThan() throws Exception {

        MockEndpoint isLowerMockEndpoint = getMockEndpoint("mock:isLower");
        isLowerMockEndpoint.expectedMessageCount(1);
        
        HashMap<String, Object> headers = createHashmapForNameAndIdHeaders(null, 3);
        template.sendBodyAndHeaders("direct:simpleComparison", null, headers);

        isLowerMockEndpoint.assertIsSatisfied();
    }

    @Test
    public void predicateComparisonSixIsGreater() throws Exception  {

        MockEndpoint isGreaterMockEndpoint = getMockEndpoint("mock:isGreater");
        isGreaterMockEndpoint.expectedMessageCount(1);

        HashMap<String, Object> headers = createHashmapForNameAndIdHeaders(null, 6);
        template.sendBodyAndHeaders("direct:predicateComparison", null, headers);

        isGreaterMockEndpoint.assertIsSatisfied();
    }

    @Test
    public void predicateComparisonThreeIsLowerThan() throws Exception {

        MockEndpoint isLowerMockEndpoint = getMockEndpoint("mock:isLower");
        isLowerMockEndpoint.expectedMessageCount(1);
        
        HashMap<String, Object> headers = createHashmapForNameAndIdHeaders(null, 3);
        template.sendBodyAndHeaders("direct:predicateComparison", null, headers);

        isLowerMockEndpoint.assertIsSatisfied();
    }

    @Override
    protected RoutesBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {

            @Override
            public void configure() throws Exception {
                
                // Using simple language
                from("direct:simpleComparison")
                    .routeId("simpleComparison")
                    .choice().when(simple("${header.name} == null && ${header.id} > 5"))
                        .log("Body value is greater than 5")
                        .to("mock:isGreater")
                    .otherwise()
                        .log("Body value is less than 5")
                        .to("mock:isLower")
                    .end()
                ;

                // Using predicate
                Predicate nameIsNullAndIdGreaterThanFive = PredicateBuilder.and(
                    header("name").isEqualTo(null),
                    header("id").isGreaterThan(5)
                );

                from("direct:predicateComparison")
                    .routeId("predicateComparison")
                    .choice().when(nameIsNullAndIdGreaterThanFive)
                        .log("Body value is greater than 5")
                        .to("mock:isGreater")
                    .otherwise()
                        .log("Body value is less than 5")
                        .to("mock:isLower")
                    .end();

            }
        };
    }

    private HashMap<String, Object> createHashmapForNameAndIdHeaders(String name, Integer id) {
        HashMap<String, Object> headers = new HashMap<>();
        headers.put("name", name);
        headers.put("id", id);
        return headers;
    }
}