/**
 * 创建索引
 *
 * @author: xiaobaoqiu  Date: 15-9-8 Time: 下午4:04
 */
public final class Indexer {

    public static void main(String[] args) {
        indexDocs(CommonConfig.SOURCE_FILE_DIR, CommonConfig.INDEX_FILE_DIR, true);
    }

    /**
     * 构建磁盘索引
     *
     * @param dirPath 原始文件
     * @param indexPath 索引文件存放路径
     * @param create    创建or更新
     */
    public static void indexDocs(String dirPath, String indexPath, boolean create) {
        try {
            Directory dir = FSDirectory.open(new File(indexPath));
            Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_4_10_0);
            IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_4_10_0, analyzer);

            if (create) {
                iwc.setOpenMode(IndexWriterConfig.OpenMode.CREATE);
            } else {
                iwc.setOpenMode(IndexWriterConfig.OpenMode.CREATE_OR_APPEND);
            }

            IndexWriter writer = new IndexWriter(dir, iwc);
            doIndexDocs(writer, new File(dirPath));

            System.out.println("Build index finished...");
            writer.close();
        }catch (IOException ioe) {
            //do something...
        }
    }

    static void doIndexDocs(IndexWriter writer, File file) throws IOException {
        if (!file.canRead()) {
            System.out.println("文件不可读:" + file.getAbsolutePath());
            return;
        }

        //文件夹则索引文件夹下的索引文件
        if (file.isDirectory()) {
            String[] files = file.list();
            if (files != null) {
                for (int i = 0; i < files.length; i++) {
                    doIndexDocs(writer, new File(file, files[i]));
                }
            }
        } else {
            doIndexFile(writer, file);
        }
    }

    /**
     * 索引一个文件
     *
     * @param writer
     * @param file
     */
    private static void doIndexFile(IndexWriter writer, File file) throws IOException{
        //单个文件
        FileInputStream fis;
        try {
            fis = new FileInputStream(file);
        } catch (FileNotFoundException fnfe) {
            //do nothing
            return;
        }

        try {
            // 创建一个新的空的Document
            Document doc = new Document();

            //文件路径字段
            doc.add(new StringField(CommonConfig.PATH_FIELD_NAME, file.getPath(), Field.Store.YES));
            //文件最后修改时间字段
            doc.add(new LongField(CommonConfig.MODIFIED_FIELD_NAME, file.lastModified(), Field.Store.NO));
            //文件内容,不存储原始串
            doc.add(new TextField(CommonConfig.CONTENTS_FIELD_NAME, new BufferedReader(new InputStreamReader(fis, StandardCharsets.UTF_8))));

            //新建索引 or 更新索引
            if (writer.getConfig().getOpenMode() == IndexWriterConfig.OpenMode.CREATE) {
                writer.addDocument(doc);
            } else {
                writer.updateDocument(new Term("path", file.getPath()), doc);
            }
        } finally {
            fis.close();
        }
    }
}

/**
 * 查询索引
 * 接受用户输入作为Query词
 *
 * @author: xiaobaoqiu  Date: 15-9-8 Time: 下午4:09
 */
public final class Searcher {

    public static void main(String[] args) throws Exception {
        search(CommonConfig.INDEX_FILE_DIR, CommonConfig.CONTENTS_FIELD_NAME);
    }

    public static void search(String indexPath, String field) throws Exception {
        IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(indexPath)));
        IndexSearcher searcher = new IndexSearcher(reader);
        Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_4_10_0);
        QueryParser parser = new QueryParser(Version.LUCENE_4_10_0, field, analyzer);

        //接受用户输入
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
        String queryString = null;
        while (StringUtils.isNotEmpty(queryString = in.readLine())) {
            Query query = parser.parse(queryString.trim());

            doSearch(searcher, query);
        }
        reader.close();
    }

    public static void doSearch(IndexSearcher searcher, Query query) throws IOException {
        // 搜索 CommonConfig.SEARCH_MAX_ITEM_COUNT 个数据
        TopDocs results = searcher.search(query, CommonConfig.SEARCH_MAX_ITEM_COUNT);
        ScoreDoc[] hits = results.scoreDocs;
        int numTotalHits = results.totalHits;
        System.out.println(numTotalHits + " total matching documents");

        if (ArrayUtils.isEmpty(hits)) return;

        for (ScoreDoc hit : hits) {
            System.out.println();
            Document hitDoc = searcher.doc(hit.doc);
            System.out.println(CommonConfig.PATH_FIELD_NAME + " = " + hitDoc.get(CommonConfig.PATH_FIELD_NAME) +
                    "\n" + CommonConfig.MODIFIED_FIELD_NAME + " = " + hitDoc.get(CommonConfig.MODIFIED_FIELD_NAME) +
                    "\n" + CommonConfig.CONTENTS_FIELD_NAME + " = " + hitDoc.get(CommonConfig.CONTENTS_FIELD_NAME));
        }
    }
}