com.mongodb.internal.connection

Class ReplyHeader

java.lang.Object

com.mongodb.internal.connection.ReplyHeader

public final class ReplyHeader
extends java.lang.Object

Contains the details of a reply from a MongoDB server.

Field Summary

Fields

Modifier and Type	Field and Description
static int	REPLY_HEADER_LENGTH The length of the OP_REPLY header in the MongoDB wire protocol.
static int	TOTAL_REPLY_HEADER_LENGTH The length of the OP_REPLY header plus the length of the standard message header

Method Summary

Modifier and Type	Method and Description
long	getCursorId() Gets the cursor ID that this response is a part of.
int	getMessageLength() Gets the total size of the message in bytes.
int	getNumberReturned() Gets the number of documents to expect in the body of this reply.
int	getRequestId() This is a client or database-generated identifier that uniquely identifies this message.
int	getResponseFlags() Gets additional information about the response.
int	getResponseTo() Along with the requestID field in queries, clients can use this to associate query responses with the originating query.
int	getStartingFrom() Returns the position in the cursor that is the start point of this reply.
boolean	isCursorNotFound() Gets whether this query was performed with a cursor ID that was not valid on the server.
boolean	isQueryFailure() Gets whether the query failed or not.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

REPLY_HEADER_LENGTH

public static final int REPLY_HEADER_LENGTH

The length of the OP_REPLY header in the MongoDB wire protocol.

See Also:

Constant Field Values

TOTAL_REPLY_HEADER_LENGTH

public static final int TOTAL_REPLY_HEADER_LENGTH

The length of the OP_REPLY header plus the length of the standard message header

See Also:

Constant Field Values

Method Detail

getMessageLength

public int getMessageLength()

Gets the total size of the message in bytes. This total includes the 4 bytes that holds the message length.

Returns:

the total message size, including all of the header

getRequestId

public int getRequestId()

This is a client or database-generated identifier that uniquely identifies this message. Along with the responseTo field in responses, clients can use this to associate query responses with the originating query.

Returns:

the identifier for this message

getResponseTo

public int getResponseTo()

Along with the requestID field in queries, clients can use this to associate query responses with the originating query.

Returns:

the request ID from the original request

getResponseFlags

public int getResponseFlags()

Gets additional information about the response.

• 0 - CursorNotFound: Set when getMore is called but the cursor id is not valid at the server. Returned with zero results.
• 1 - QueryFailure: Set when query failed. Results consist of one document containing an "$err" field describing the failure.
• 2 - ShardConfigStale: Drivers should ignore this. Only mongos will ever see this set, in which case, it needs to update config from the server.
• 3 - AwaitCapable: Set when the server supports the AwaitData Query option. If it doesn't, a client should sleep a little between getMore's of a Tailable cursor. Mongod version 1.6 supports AwaitData and thus always sets AwaitCapable.
• 4-31 - Reserved: Ignore

Returns:

bit vector - see details above

getCursorId

public long getCursorId()

Gets the cursor ID that this response is a part of. If there are no more documents to fetch from the server, the cursor ID will be 0. This cursor ID must be used in any messages used to get more data, and also must be closed by the client when no longer needed.

Returns:

cursor ID to use if the client needs to fetch more from the server

getStartingFrom

public int getStartingFrom()

Returns the position in the cursor that is the start point of this reply.

Returns:

where in the cursor this reply is starting

getNumberReturned

public int getNumberReturned()

Gets the number of documents to expect in the body of this reply.

Returns:

number of documents in the reply

isCursorNotFound

public boolean isCursorNotFound()

Gets whether this query was performed with a cursor ID that was not valid on the server.

Returns:

true if this reply indicates the request to get more data was performed with a cursor ID that's not valid on the server

isQueryFailure

public boolean isQueryFailure()

Gets whether the query failed or not.

Returns:

true if this reply indicates the query failed.