backend/src/main/java/nju/seec/helper/api/bok/QuestionQueryApi.java

package nju.seec.helper.api.bok;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.gson.reflect.TypeToken;
import lombok.Data;
import nju.seec.helper.api.bok.vo.QuestionVO;
import nju.seec.helper.util.JsonUtils;
import nju.seec.helper.util.RestRequestUtil;
import nju.seec.helper.util.cache.CaffeineCacheUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

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

/**
 * @author cst
 */
@Component
@ConfigurationProperties("bok.question-query")
@Data
public class QuestionQueryApi {
    @Value("${bok.question-cache-name}")
    private String bokQuestionCacheName;

    private final RestRequestUtil restRequestUtil;
    private final CaffeineCacheUtils cacheUtils;

    private String byIdUrl;

    public QuestionQueryApi(RestRequestUtil restRequestUtil, CaffeineCacheUtils cacheUtils) {
        this.restRequestUtil = restRequestUtil;
        this.cacheUtils = cacheUtils;
    }

    @SuppressWarnings({"unchecked", "rawtypes"})
    public List<QuestionVO> getQuestionListById(final List<String> ids) {
        Map<String, QuestionVO> bokQuestionsMap = Maps.newHashMapWithExpectedSize(ids.size());

        final Map<String, QuestionVO> cacheBokQuestionsMap = (Map) cacheUtils.multiGet(bokQuestionCacheName, ids);
        bokQuestionsMap.putAll(cacheBokQuestionsMap);

        List<String> requestIds = Lists.newArrayList(ids);
        requestIds.removeAll(cacheBokQuestionsMap.keySet());
        //未缓存的去这里拿
        if (!requestIds.isEmpty()) {
            Map<String, String> uriVariables = ImmutableMap.of("id", requestIds.stream().reduce((a, b) -> a + "," + b).orElse(""));

            List<QuestionVO> questionVOList = JsonUtils.fromJson(restRequestUtil.sendGetRequest(byIdUrl, String.class, uriVariables), new TypeToken<List<QuestionVO>>() {
            });

            Map<String, QuestionVO> remoteBokQuestionsMap = questionVOList.parallelStream().collect(Collectors.toMap(QuestionVO::getId, bokQuestion -> bokQuestion));

            bokQuestionsMap.putAll(remoteBokQuestionsMap);
            cacheUtils.setAll(bokQuestionCacheName, (Map) remoteBokQuestionsMap);
        }

        return ids.stream()
                .map(bokQuestionsMap::get)
                .collect(Collectors.toList());
    }
}