uploadreaper.java

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package com.redmoon.kit.util;

import java.util.Vector;
import java.util.Iterator;
import org.apache.log4j.Logger;
import java.util.Map;
import java.util.Collections;
import java.util.Set;
import java.io.IOException;
import java.io.File;

public class UploadReaper extends Thread {
    Logger logger = Logger.getLogger(UploadReaper.class.getName());

    private static long reapInterval = 1000*60*60*6; // 每隔6小时刷新一次
    private static UploadReaper uploadReaper = null;

    private final long expireTimeLen = 1000*60*60*6; // 超期时长为6小时

    /**
     * Creates a new CacheTimer object. The currentTime of Cache will be
     * updated at the specified update interval.
     *
     * @param updateInterval the interval in milleseconds that updates should
     *    be done.
     */
    public UploadReaper(long reapInterval) {
        this.reapInterval = reapInterval;
        // Make the timer be a daemon thread so that it won't keep the VM from
        // shutting down if there are no other threads.
        this.setDaemon(true);
        // Start the timer thread.
        start();
    }

    public static long getReapInterval() {
        return reapInterval;
    }

    /**
     * 单态模式
     * @param updateInterval long
     */
    public static synchronized void initInstance(long reapInterval) {
        if (uploadReaper==null)
            uploadReaper = new UploadReaper(reapInterval);
    }

    public void run() {
        // Run the timer indefinetly.
        while (true) {
            // 遍历链表，如果有超期的文件则将其线程所对应的文件块删除（一个线程对应于一个文件块，一个文件块在上传时由多个Segment组成）
            // 并将其从链表中删除
            Map m = UploadDdxc.uploadFileInfos;
            Set s = m.keySet(); // Needn't be in synchronized block
            Vector expireUfis = new Vector();
            synchronized (m) { // Synchronizing on m, not s!
                Iterator i = s.iterator(); // Must be in synchronized block
                while (i.hasNext()) {
                    UploadFileInfo ufi = (UploadFileInfo) i.next();
                    if (System.currentTimeMillis() - ufi.getReceiveTime() >
                        expireTimeLen) {
                        // 记录将删除的key
                        expireUfis.addElement(ufi.getFileId());
                        // 删除线程及相关文件
                        Vector v = ufi.getUploadThreadInfos();
                        Iterator ir = v.iterator();
                        while (ir.hasNext()) {
                            UploadThreadInfo uti = (UploadThreadInfo) ir.next();
                            // 删除文件块（每个线程对应一个文件块）
                            String blockPath = FileUpload.getTmpPath() +
                                               ufi.getBlockName(uti.getBlockId());
                            File file = new File(blockPath);
                            if (!(file.exists()))
                                file.delete();
                        }
                    }
                }
                // 从链表中删除超期的FileUploadInfo
                Iterator ir = expireUfis.iterator();
                while (ir.hasNext()) {
                    String fileId = (String)ir.next();
                    UploadDdxc.uploadFileInfos.remove(fileId);
                    System.out.println("UploadReaper run: Delete UploadFileInfo " + fileId);
                }
            }
            try {
                sleep(reapInterval);
            }
            catch (InterruptedException ie) { }
        }
    }

    public static synchronized UploadReaper getInstance() {
        if (uploadReaper==null)
            initInstance(reapInterval);
        return uploadReaper;
    }

}