QuestionsController.java

package sagan.questions.support;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.servlet.ModelAndView;
import sagan.projects.Project;
import sagan.projects.support.ProjectMetadataService;
import sagan.support.nav.Navigation;
import sagan.support.nav.Section;

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

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@Navigation(Section.QUESTIONS)
class QuestionsController {

    private final ProjectMetadataService projectMetadata;
    private final StackOverflowClient stackOverflow;

    private final Log logger = LogFactory.getLog(QuestionsController.class);

    @Autowired
    public QuestionsController(ProjectMetadataService projectMetadata, StackOverflowClient stackOverflow) {
        this.projectMetadata = projectMetadata;
        this.stackOverflow = stackOverflow;
    }

    @ExceptionHandler(HttpClientErrorException.class)
    public ModelAndView handleStackOverflowAPIException(HttpClientErrorException clientErrorException) {

        logger.error("Error while fetching questions from StackOverflow API", clientErrorException);
        ModelAndView mav = new ModelAndView("questions/index");
        mav.addObject("questions", Collections.emptyList());
        mav.addObject("projects", getProjectList());

        return mav;
    }

    @RequestMapping("/questions")
    public String show(Model model) {

        model.addAttribute("questions", stackOverflow.searchForQuestionsTagged("spring"));
        model.addAttribute("projects", getProjectList());

        return "questions/index";
    }

    private List<Project> getProjectList() {

        return projectMetadata.getProjects().stream()
                .filter(project -> !project.getCategory().equals("attic"))
                .filter(project -> !project.getStackOverflowTagList().isEmpty())
                .sorted((p1, p2) -> p1.getName().compareToIgnoreCase(p2.getName()))
                .collect(Collectors.toList());
    }

}