protected synchronized Message receiveMessage() throws IOException {
if (messageBuffer.size() > 0) {
Message m = (Message) messageBuffer.get(0);
messageBuffer.remove(0);
return m;
}
try {
InetSocketAddress remoteAddress = (InetSocketAddress) channel.receive(receiveBuffer);
if (remoteAddress != null) {
int len = receiveBuffer.position();
receiveBuffer.rewind();
receiveBuffer.get(buf, 0, len);
try {
IP address = IP.fromInetAddress(remoteAddress.getAddress());
int port = remoteAddress.getPort();
extractor.appendData(buf, 0, len, new SocketDescriptor(address, port));
receiveBuffer.clear();
extractor.updateAvailableMessages();
return extractor.nextMessage();
} catch (EOFException exc) {
exc.printStackTrace();
System.err.println(buf.length + ", " + len);
} catch (InvocationTargetException exc) {
exc.printStackTrace();
} catch (IllegalAccessException exc) {
exc.printStackTrace();
} catch (InstantiationException exc) {
exc.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvalidCompressionMethodException e) {
e.printStackTrace();
}
}
} catch (ClosedChannelException exc) {
if (isKeepAlive()) {
throw exc;
}
}
return null;
}
// 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;
}
// check if compressed file seems ok
public static long testValid(String ufilename) throws IOException {
boolean lookForHeader = false;
// gotta make it
RandomAccessFile raf = new RandomAccessFile(ufilename, "r");
raf.order(RandomAccessFile.BIG_ENDIAN);
raf.seek(0);
byte[] b = new byte[8];
raf.read(b);
String test = new String(b);
if (test.equals(Level2VolumeScan.ARCHIVE2) || test.equals(Level2VolumeScan.AR2V0001)) {
System.out.println("--Good header= " + test);
raf.seek(24);
} else {
System.out.println("--No header ");
lookForHeader = true;
raf.seek(0);
}
boolean eof = false;
int numCompBytes;
try {
while (!eof) {
if (lookForHeader) {
raf.read(b);
test = new String(b);
if (test.equals(Level2VolumeScan.ARCHIVE2) || test.equals(Level2VolumeScan.AR2V0001)) {
System.out.println(" found header= " + test);
raf.skipBytes(16);
lookForHeader = false;
} else {
raf.skipBytes(-8);
}
}
try {
numCompBytes = raf.readInt();
if (numCompBytes == -1) {
System.out.println("\n--done: numCompBytes=-1 ");
break;
}
} catch (EOFException ee) {
System.out.println("\n--got EOFException ");
break; // assume this is ok
}
System.out.print(" " + numCompBytes + ",");
if (numCompBytes < 0) {
System.out.println("\n--last block " + numCompBytes);
numCompBytes = -numCompBytes;
if (!lookForHeader) eof = true;
}
raf.skipBytes(numCompBytes);
}
} catch (EOFException e) {
e.printStackTrace();
}
return raf.getFilePointer();
}