// see DbFile.java for javadocs
public Page readPage(PageId pid) {
int offset = BufferPool.PAGE_SIZE * pid.pageNumber();
byte[] b = new byte[BufferPool.PAGE_SIZE];
try {
InputStream is = new FileInputStream(m_file);
is.skip(offset);
is.read(b, 0, BufferPool.PAGE_SIZE);
is.close();
return new HeapPage((HeapPageId) pid, b);
} catch (IOException ioe) {
ioe.printStackTrace();
return null;
}
}
/**
* Compares one PageId to another.
*
* @param o The object to compare against (must be a PageId)
* @return true if the objects are equal (e.g., page numbers and table ids are the same)
*/
public boolean equals(Object o) {
if (!(o instanceof PageId)) return false;
PageId other = (PageId) o;
if (this.getTableId() != other.getTableId() || this.pageNumber() != other.pageNumber())
return false;
return true;
}
// see DbFile.java for javadocs
public Page readPage(PageId pid) {
// some code goes here
if (pid.pageNumber() >= numPages()) {
throw new IllegalArgumentException("page not in file");
}
Page returnme = null;
byte[] data = HeapPage.createEmptyPageData();
long offset = (long) BufferPool.PAGE_SIZE * pid.pageNumber();
try {
raf.seek(offset);
for (int i = 0; i < data.length; i++) {
data[i] = raf.readByte();
}
returnme = new HeapPage((HeapPageId) pid, data);
} catch (EOFException eofe) {
eofe.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
}
return returnme;
}
// see DbFile.java for javadocs
public Page readPage(PageId pid) {
// some code goes here
try {
RandomAccessFile rAf = new RandomAccessFile(f, "r");
int offset = pid.pageNumber() * BufferPool.PAGE_SIZE;
byte[] b = new byte[BufferPool.PAGE_SIZE];
rAf.seek(offset);
rAf.read(b, 0, BufferPool.PAGE_SIZE);
HeapPageId hpid = (HeapPageId) pid;
rAf.close();
return new HeapPage(hpid, b);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
