RulesController.java

package camelinaction;

import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

import org.apache.camel.FluentProducerTemplate;
import org.apache.camel.Produce;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

/**
 * Spring REST controller to setup the REST service.
 * <p/>
 * Notice that this code is almost identical to the JAX-RS code from the WildFly Swarm example.
 * The only different is that this code is using Spring REST instead of JAX-RS
 */
@RestController
@RequestMapping("/api")
@ConfigurationProperties(prefix = "rules") // inject properties from application.properties using this prefix
public class RulesController {

    // inject Camel template to call the Camel route from java code
    @Produce(uri = "direct:inventory")
    private FluentProducerTemplate producer;

    @RequestMapping(value = "rules/{cartIds}", method = RequestMethod.GET, produces = "application/json")
    public List<ItemDto> rules(@PathVariable String cartIds) {
        // find all items in inventory (use Camel to call legacy system)
        ItemsDto inventory = producer.request(ItemsDto.class);

        return inventory.getItems().stream()
            // filter out duplicate from the shopping cart
            .filter((i) -> cartIds == null || !cartIds.contains("" + i.getItemNo()))
            // sort the items
            .sorted(new ItemSorter())
            // and collect to the list to use for response
            .collect(Collectors.toList());
    }

    /**
     * Used for sorting the items to recommend.
     */
    private static class ItemSorter implements Comparator<ItemDto> {

        @Override
        public int compare(ItemDto o1, ItemDto o2) {
            Integer n1 = o1.getNumber();
            Integer n2 = o2.getNumber();
            // we want the items with the highest number in our inventory first so -1
            return n1.compareTo(n2) * -1;
        }
    }

}