com.aquenos.epics.jackie.common.protocol

Class ChannelAccessVersionTCPClientMessage

java.lang.Object

com.aquenos.epics.jackie.common.protocol.ChannelAccessMessage

com.aquenos.epics.jackie.common.protocol.ChannelAccessVersionMessage

com.aquenos.epics.jackie.common.protocol.ChannelAccessVersionTCPClientMessage

public final class ChannelAccessVersionTCPClientMessage
extends ChannelAccessVersionMessage

Representation of a CA_PROTO_VERSION message that is sent from a client to a server via TCP. This message is usually send at the start of a new TCP connection in order to communicate the protocol version supported by the client and set the priority that should be associated with this connection. However, some servers might not consider the specified priority.

Author:

Sebastian Marsching

See Also:

ChannelAccessCommand.CA_PROTO_VERSION, ChannelAccessVersionUDPMessage, ChannelAccessVersionTCPServerMessage

Field Summary

Fields inherited from class com.aquenos.epics.jackie.common.protocol.ChannelAccessVersionMessage

version

Fields inherited from class com.aquenos.epics.jackie.common.protocol.ChannelAccessMessage

command, originalMessageHeader

Constructor Summary

Constructors

Constructor and Description
ChannelAccessVersionTCPClientMessage(ChannelAccessVersion version, short priority) Creates a CA_PROTO_VERSION message.

Method Summary

Modifier and Type	Method and Description
protected static ChannelAccessVersionTCPClientMessage	deserialize(ChannelAccessMessageHeader messageHeader, ByteSource byteSource, boolean headerOnly) Constructs a message from a header and a byte source.
boolean	equals(java.lang.Object obj) Tells whether the specified object represents the same message.
short	getPriority() Returns the priority requested by the client.
int	hashCode() Returns a hash code value for this message.
protected void	serialize(ByteSink byteSink, ChannelAccessVersion version, int maxPayloadSize, java.nio.charset.Charset charset) Serializes this message to a byte sink.
java.lang.String	toString() Returns a string representation of this message.

Methods inherited from class com.aquenos.epics.jackie.common.protocol.ChannelAccessVersionMessage

getVersion

Methods inherited from class com.aquenos.epics.jackie.common.protocol.ChannelAccessMessage

addByteArrayToStringBuilder, calculatePaddingSize, getCommand, getOriginalMessageHeader, hasOriginalMessageHeader, serializeHeader, verify, verifyHeader

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ChannelAccessVersionTCPClientMessage

public ChannelAccessVersionTCPClientMessage(ChannelAccessVersion version,
                                            short priority)

Creates a CA_PROTO_VERSION message. This constructor should be used to create a message that is supposed to be sent from a client to a server using the TCP protocol.

Parameters:

version - Channel Access version supported by the client.

priority - priority that should be associated with this TCP connection. This number must be between ChannelAccessConstants.MIN_PRIORITY and ChannelAccessConstants.MAX_PRIORITY. Higher numbers mean a higher priority.

Throws:

InvalidPriorityException - if the specified priority is out of range.

Method Detail

getPriority

public short getPriority()

Returns the priority requested by the client.

Returns:

the priority requested by the client. This is a value between ChannelAccessConstants.MIN_PRIORITY and ChannelAccessConstants.MAX_PRIORITY.

serialize

protected void serialize(ByteSink byteSink,
                         ChannelAccessVersion version,
                         int maxPayloadSize,
                         java.nio.charset.Charset charset)

Description copied from class: ChannelAccessMessage

Serializes this message to a byte sink. This method is only intended to be used by ChannelAccessMessageCodec.

Specified by:

serialize in class ChannelAccessMessage

Parameters:

byteSink - byte sink that is used for writing the serialized data.

version - protocol version to stay compatible with. This is the protocol version of the peer the message is sent to.

maxPayloadSize - maximum size of the payload.

charset - encoding to use for serializing the string data (e.g. channel names, error strings, string data-values).

equals

public boolean equals(java.lang.Object obj)

Description copied from class: ChannelAccessMessage

Tells whether the specified object represents the same message.

Two messages are considered equal if they are of the same type and have the same headers and payload. For comparing the types, the actual Java type and not just the Channel Access command is compared.

Overrides:

equals in class ChannelAccessVersionMessage

Parameters:

obj - reference object with which this object is compared.

Returns:

true if obj is a message that is of the same type and has the same headers and payload as this message. false if obj is null or of a different type than this message or differs in the headers or payload.

hashCode

public int hashCode()

Description copied from class: ChannelAccessMessage

Returns a hash code value for this message. This method is supported for the benefit of hash tables. The hash code is calculated as a combination of the hash codes of this messages headers (including the Channel Access command) and its payload (if present).

If two messages are equal (as indicated by the return value of ChannelAccessMessage.equals(Object)), they also have the same hash code. However, the fact that two messages have the same hash code does not imply that they are equal.

Overrides:

hashCode in class ChannelAccessVersionMessage

Returns:

hash code suitable for use by a hash table.

toString

public java.lang.String toString()

Description copied from class: ChannelAccessMessage

Returns a string representation of this message. The string representation contains the messages command, its header fields (if relevant for the command type) and its payload if present.

Overrides:

toString in class ChannelAccessMessage

Returns:

string representation of this message.

deserialize

protected static ChannelAccessVersionTCPClientMessage deserialize(ChannelAccessMessageHeader messageHeader,
                                                                  ByteSource byteSource,
                                                                  boolean headerOnly)

Constructs a message from a header and a byte source. This method is only intended for use by ChannelAccessMessageCodec.

Parameters:

messageHeader - CA message header.

byteSource - byte source for reading the message's payload (if any).

headerOnly - if true this method will not try to read the payload but just read the header. This is useful for reading a message that is sent in the payload of a ChannelAccessErrorMessage. Such a message will have all headers but no payload (even so the payload size might be non-zero).

Returns:

message constructed from the data in the header and the payload read from the byte source.

Throws:

java.nio.BufferUnderflowException - if there is not enough data in the byte source to read the complete payload.

InvalidPriorityException - if the priority specified in the message header is out of range.