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72 lines
2.3 KiB
72 lines
2.3 KiB
package com.personalproject.service;
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import com.personalproject.generator.QuestionGenerator;
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import com.personalproject.model.DifficultyLevel;
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import java.security.SecureRandom;
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import java.util.ArrayList;
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import java.util.EnumMap;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Map;
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import java.util.Random;
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import java.util.Set;
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/**
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* 负责批量生成题目并避免与历史题库重复.
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*/
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public final class QuestionGenerationService {
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private static final int MAX_ATTEMPTS = 10_000;
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private final Map<DifficultyLevel, QuestionGenerator> generators;
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private final Random random = new SecureRandom();
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/**
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* 构造函数：复制难度与生成器的映射，保留内部安全副本.
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*
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* @param generatorMap 难度到题目生成器的外部映射.
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*/
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public QuestionGenerationService(Map<DifficultyLevel, QuestionGenerator> generatorMap) {
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generators = new EnumMap<>(DifficultyLevel.class);
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generators.putAll(generatorMap);
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}
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/**
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* 根据指定难度批量生成不与历史题目重复的新题目.
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*
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* @param level 目标题目难度.
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* @param count 需要生成的题目数量.
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* @param existingQuestions 已存在的题目集合，用于查重.
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* @return 生成的题目列表.
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* @throws IllegalArgumentException 当难度未配置时抛出.
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* @throws IllegalStateException 当达到最大尝试次数仍无法生成足够题目时抛出.
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*/
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public List<String> generateUniqueQuestions(
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DifficultyLevel level, int count, Set<String> existingQuestions) {
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QuestionGenerator generator = generators.get(level);
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if (generator == null) {
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throw new IllegalArgumentException("Unsupported difficulty level: " + level);
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}
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Set<String> produced = new HashSet<>();
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List<String> results = new ArrayList<>();
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int attempts = 0;
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while (results.size() < count) {
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if (attempts >= MAX_ATTEMPTS) {
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throw new IllegalStateException("Unable to generate enough unique questions.");
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}
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attempts++;
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String question = generator.generateQuestion(random).trim();
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if (question.isEmpty()) {
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continue;
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}
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if (existingQuestions.contains(question)) {
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continue;
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}
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if (!produced.add(question)) {
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continue;
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}
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results.add(question);
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}
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return results;
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}
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}
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