Exemplo n.º 1
0
  /**
   * Searches the directory for a data page with enough free space to store a record of the given
   * size. If no suitable page is found, this creates a new data page.
   */
  protected PageId getAvailPage(int reclen) {
    for (int i = 0; i < pages.size(); i++) {
      PageId pid = pages.get(i);
      Page page = new Page();
      global.Minibase.BufferManager.pinPage(pid, page, false);
      HFPage hfpage = new HFPage();
      hfpage.copyPage(page);
      if (hfpage.getFreeSpace() >= reclen) {
        global.Minibase.BufferManager.unpinPage(pid, true);
        return pid;
      }
      global.Minibase.BufferManager.unpinPage(pid, false);
    }

    Page page = new Page();
    PageId pid = global.Minibase.BufferManager.newPage(page, 1);
    HFPage hfpage = new HFPage(page);
    // initialize HFPage
    hfpage.setCurPage(pid);
    pages.add(pid);
    pids.add(pid.pid);
    current.setNextPage(pid);
    hfpage.setPrevPage(current.getCurPage());
    current = hfpage;
    global.Minibase.BufferManager.unpinPage(pid, true);
    return pid;
  }
Exemplo n.º 2
0
 /**
  * Deletes the specified record from the heap file.
  *
  * @throws IllegalArgumentException if the rid is invalid
  */
 public boolean deleteRecord(RID rid) {
   PageId pid = rid.pageno;
   if (!pids.contains(pid.pid)) throw new IllegalArgumentException("the rid is invalid");
   try {
     Page page = new Page();
     global.Minibase.BufferManager.pinPage(pid, page, false);
     HFPage hfpage = new HFPage();
     hfpage.copyPage(page);
     hfpage.deleteRecord(rid);
     global.Minibase.BufferManager.unpinPage(pid, true);
     recordNumber--;
     return true;
   } catch (Exception e) {
     System.err.print("fail to delete record");
     return false;
   }
 }