@Component
public class SearchSpecification {

public static Specification<Task> locationNameContains(String location) {
    return (root, query, cb) -> cb.like(root.get(Task_.location), "%"+location.toLowerCase()+"%");
}

public static Specification<Task> titleContainsQuery(String title) {
    return (root, query, cb) -> cb.like(root.get(Task_.title), "%"+ title + "%");
}

public static Specification<Task> titleOrDescriptionContains(String searchTerm) {
    return (root, query, cb) ->  {
        query.distinct(true);
        return cb.or(
                cb.like(root.get(Task_.title), "%"+ searchTerm.toLowerCase() + "%"),
                cb.like(root.get(Task_.description), "%"+ searchTerm.toLowerCase() + "%")
        );
    };
}

public static Specification<Task> categoryContains(Category category) {
    return (root, query, cb) ->  {
        query.distinct(true);
        return cb.equal(root.get(Task_.category), category);
    };
}

public List<TaskResponse> searchTasksBySpecification(String query, String category, String location) throws Exception {
    ArrayList<TaskResponse> jobs = new ArrayList<>();
    Category categoryByTitle = categoryRepository.findByTitle(category);

    if (query == null &&
        category == null &&
        location == null) {
        taskRepository.findAllByOrderByCreatedDateDesc().forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (category == null && location == null) {
        taskRepository.findAll(where(titleOrDescriptionContains(query))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (query == null && category == null) {
        taskRepository.findAll(where(locationNameContains(location))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (query == null && location == null) {
        taskRepository.findAll(where(categoryContains(categoryByTitle))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (query == null) {
        taskRepository.findByCategory_TitleAndLocationOrderByCreatedDateDesc(category, location).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (category == null) {
        taskRepository.findAll(where(titleOrDescriptionContains(query)
                .and(locationNameContains(location)))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else if (location == null) {
        taskRepository.findAll(where(titleOrDescriptionContains(query)
                .and(categoryContains(categoryByTitle)))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
        return jobs;

    } else
        taskRepository.findAll(where(titleOrDescriptionContains(query)
                .and(categoryContains(categoryByTitle))
                .and(locationNameContains(location)))).forEach(taskEntity -> {
            if (taskEntity.getIsOpen()) {
                TaskResponse job = DTOMapper.map(taskEntity, TaskResponse.class);
                jobs.add(job);
            }
        });
    return jobs;
}

taskRepository.findAll(where(titleOrDescriptionContains(query)
            .and(categoryContains(categoryByTitle))
            .and(locationNameContains(location))))