com.mysql.cj.protocol

Interface MessageReader<H extends MessageHeader,M extends Message>

All Known Implementing Classes:

DebugBufferingPacketReader, MultiPacketReader, SimplePacketReader, SyncMessageReader, TimeTrackingPacketReader, TracingPacketReader

public interface MessageReader<H extends MessageHeader,M extends Message>

Method Summary

Modifier and Type	Method and Description
default byte	getMessageSequence() Get last message sequence number, as it was stored by readHeader().
default H	probeHeader() Read the next message header from server, possibly blocking indefinitely until the message is received, and cache it so that the next readHeader() return the same header.
default M	probeMessage(java.util.Optional<M> reuse, H header) Read message from server into to the given Message instance or into the new one if not present and cache it so that the next readMessage(Optional, MessageHeader) return the same message.
default void	pushMessageListener(MessageListener<M> l) Queue a MessageListener to receive messages delivered asynchronously.
H	readHeader() Read the next message header from server, possibly blocking indefinitely until the message is received.
M	readMessage(java.util.Optional<M> reuse, H header) Read message from server into to the given Message instance or into the new one if not present.
default M	readMessage(java.util.Optional<M> reuse, int expectedType) Read message from server into to the given Message instance or into the new one if not present.
default void	resetMessageSequence() Set stored message sequence number to 0.
default void	start() Start reading messages reader from the provided channel.
default void	stopAfterNextMessage() Signal to the reader that it should stop reading messages after reading the next message.
default MessageReader<H,M>	undecorate() Return the previous MessageReader instance from the decorators chain or the current MessageReader if it is the first entry in a chain.
default MessageReader<H,M>	undecorateAll() Return a MessageReader instance free of decorators.

Method Detail

readHeader

H readHeader()
      throws java.io.IOException

Read the next message header from server, possibly blocking indefinitely until the message is received.

Returns:

MessageHeader of the next message

Throws:

java.io.IOException - if an error occurs

probeHeader

default H probeHeader()
               throws java.io.IOException

Read the next message header from server, possibly blocking indefinitely until the message is received, and cache it so that the next readHeader() return the same header.

Returns:

MessageHeader of the next message

Throws:

java.io.IOException - if an error occurs

readMessage

M readMessage(java.util.Optional<M> reuse,
              H header)
       throws java.io.IOException

Read message from server into to the given Message instance or into the new one if not present. For asynchronous channel it synchronously reads the next message in the stream, blocking until the message is read fully. Could throw CJCommunicationsException wrapping an IOException during read or parse

Parameters:

reuse - Message object to reuse. May be ignored by implementation.

header - MessageHeader instance

Returns:

Message instance

Throws:

java.io.IOException - if an error occurs

probeMessage

default M probeMessage(java.util.Optional<M> reuse,
                       H header)
                throws java.io.IOException

Read message from server into to the given Message instance or into the new one if not present and cache it so that the next readMessage(Optional, MessageHeader) return the same message. For asynchronous channel it synchronously reads the next message in the stream, blocking until the message is read fully. Could throw CJCommunicationsException wrapping an IOException during read or parse

Parameters:

reuse - Message object to reuse. May be ignored by implementation.

header - MessageHeader instance

Returns:

Message instance

Throws:

java.io.IOException - if an error occurs

readMessage

default M readMessage(java.util.Optional<M> reuse,
                      int expectedType)
               throws java.io.IOException

Read message from server into to the given Message instance or into the new one if not present. For asynchronous channel it synchronously reads the next message in the stream, blocking until the message is read fully. Could throw WrongArgumentException if the expected message type is not the next message (exception will be thrown in *caller* context).

Parameters:

reuse - Message object to reuse. May be ignored by implementation.

expectedType - Expected type of message.

Returns:

Message instance

Throws:

java.io.IOException - if an error occurs

pushMessageListener

default void pushMessageListener(MessageListener<M> l)

Queue a MessageListener to receive messages delivered asynchronously.

Parameters:

l - MessageListener

getMessageSequence

default byte getMessageSequence()

Get last message sequence number, as it was stored by readHeader().

Returns:

number

resetMessageSequence

default void resetMessageSequence()

Set stored message sequence number to 0.

undecorateAll

default MessageReader<H,M> undecorateAll()

Return a MessageReader instance free of decorators.

Returns:

MessageReader

undecorate

default MessageReader<H,M> undecorate()

Return the previous MessageReader instance from the decorators chain or the current MessageReader if it is the first entry in a chain.

Returns:

MessageReader

start

default void start()

Start reading messages reader from the provided channel.

stopAfterNextMessage

default void stopAfterNextMessage()

Signal to the reader that it should stop reading messages after reading the next message.