/**
* Advance to the next message or return false if there are no more messages. The cursor
* initially starts "before" the next message.
*/
public boolean next() throws IOException {
if (routingKeySize > 0) {
input.skip(routingKeySize); // routing key was never read
routingKeySize = -1;
}
if (payloadSize > 0) {
input.skip(payloadSize); // payload was never read
payloadSize = -1;
}
int len = length();
if (input.position() >= len) return false;
id = firstMessageId + input.position() - FILE_HEADER_SIZE;
byte type = input.readByte();
if (type != TYPE_MESSAGE) {
throw new IOException(
"Unexpected message type 0x"
+ Integer.toHexString(type & 0xFF)
+ " at "
+ (input.position() - 1)
+ " in "
+ MessageFile.this);
}
timestamp = input.readLong();
routingKeySize = input.readShort();
if (routingKeySize < 0 || routingKeySize >= routingKeyBuf.length) {
throw new IOException(
"Invalid routing key size "
+ routingKeySize
+ " at "
+ (input.position() - 2)
+ " in "
+ MessageFile.this);
}
payloadSize = input.readInt();
if (payloadSize < 0) {
throw new IOException(
"Negative payload size "
+ payloadSize
+ " at "
+ (input.position() - 4)
+ " in "
+ MessageFile.this);
}
nextPosition = input.position() + routingKeySize + payloadSize;
if (nextPosition > len) {
throw new IOException(
"Payload size "
+ payloadSize
+ " at "
+ (input.position() - 4)
+ " extends beyond EOF "
+ len
+ " in "
+ MessageFile.this);
}
return true;
}
private void unget() {
routingKeySize = payloadSize = -1;
input.position(messageIdToPosition(id));
}