/** * Reads a record from the file, given its id. * * @throws IllegalArgumentException if the rid is invalid */ public byte[] selectRecord(RID rid) { PageId pid = rid.pageno; if (!pids.contains(pid.pid)) throw new IllegalArgumentException("the RID is invalid"); Page page = new Page(); global.Minibase.BufferManager.pinPage(pid, page, false); global.Minibase.BufferManager.unpinPage(pid, false); return page.getData(); }
/** * If the given name already denotes a file, this opens it; otherwise, this creates a new empty * file. A null name produces a temporary heap file which requires no DB entry. */ public HeapFile(String name) throws ChainException { this.name = name; PageId firstPageId; Page page = new Page(); pages = new ArrayList<PageId>(); pids = new HashSet<Integer>(); if (name == null) { // Temporary heap file firstPageId = global.Minibase.BufferManager.newPage(page, 1); current = new HFPage(page); current.setCurPage(firstPageId); pages.add(firstPageId); pids.add(firstPageId.pid); global.Minibase.BufferManager.unpinPage(firstPageId, true); } else { firstPageId = global.Minibase.DiskManager.get_file_entry(name); if (firstPageId == null) { firstPageId = global.Minibase.BufferManager.newPage(page, 1); global.Minibase.DiskManager.add_file_entry(name, firstPageId); global.Minibase.BufferManager.unpinPage(firstPageId, true); pages.add(firstPageId); pids.add(firstPageId.pid); global.Minibase.BufferManager.pinPage(firstPageId, page, false); recordNumber = 0; current = new HFPage(page); current.setCurPage(firstPageId); global.Minibase.BufferManager.unpinPage(firstPageId, true); return; } // add the new HFPages global.Minibase.BufferManager.pinPage(firstPageId, page, false); // System.err.println("hahahaha"+page.getData()); current = new HFPage(page); current.setData(page.getData()); pages.add(firstPageId); pids.add(firstPageId.pid); recordNumber += amount(current); global.Minibase.BufferManager.unpinPage(firstPageId, false); PageId currentPageId = current.getNextPage(); while (currentPageId.pid != 0 & currentPageId.pid != -1) { HFPage temp = new HFPage(); global.Minibase.BufferManager.pinPage(currentPageId, temp, false); pages.add(currentPageId); pids.add(currentPageId.pid); recordNumber += amount(temp); global.Minibase.BufferManager.unpinPage(currentPageId, false); currentPageId = temp.getNextPage(); } } }
/** * Inserts a new record into the file and returns its RID. * * @throws IllegalArgumentException if the record is too large */ public RID insertRecord(byte[] record) throws IllegalArgumentException, ChainException { if (record.length > GlobalConst.MAX_TUPSIZE) throw new IllegalArgumentException("the record's size is too large"); 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(page); hfpage.setCurPage(pid); hfpage.setData(page.getData()); if (hfpage.getFreeSpace() > record.length) { RID rid = hfpage.insertRecord(record); recordNumber++; global.Minibase.BufferManager.unpinPage(pid, true); return rid; } 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.initDefaults(); hfpage.setCurPage(pid); // hfpage.print(); RID rid = hfpage.insertRecord(record); pages.add(pid); pids.add(pid.pid); hfpage.setNextPage(pid); hfpage.setPrevPage(current.getCurPage()); current = hfpage; global.Minibase.BufferManager.unpinPage(pid, true); // hfpage.print(); // System.out.println ("The PID is "+pid); recordNumber++; return rid; }