com.aquenos.epics.jackie.common.protocol

Class ChannelAccessConnectChannelClientMessage

java.lang.Object

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

com.aquenos.epics.jackie.common.protocol.ChannelAccessConnectChannelMessage

com.aquenos.epics.jackie.common.protocol.ChannelAccessConnectChannelClientMessage

public final class ChannelAccessConnectChannelClientMessage
extends ChannelAccessConnectChannelMessage

Representation of a CA_PROTO_CREATE_CHAN message that is sent from a client to a server. This message is sent in order to connect to a channel. Multiple channels can be connected within the same TCP connection.

Author:

Sebastian Marsching

See Also:

ChannelAccessCommand.CA_PROTO_CREATE_CHAN, ChannelAccessConnectChannelServerMessage, ChannelAccessConnectChannelFailedMessage

Field Summary

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

command, originalMessageHeader

Constructor Summary

Constructors

Constructor and Description
ChannelAccessConnectChannelClientMessage(int cid, ChannelAccessVersion version, java.lang.String channelName) Creates a CA_PROTO_CREATE_CHAN message.

Method Summary

Modifier and Type	Method and Description
protected static ChannelAccessConnectChannelClientMessage	deserialize(ChannelAccessMessageHeader messageHeader, ByteSource byteSource, boolean headerOnly, java.nio.charset.Charset charset) 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.
int	getChannelCID() Returns the channel CID used by the client.
java.lang.String	getChannelName() Returns the name of the channel that the client wants to connect to.
ChannelAccessVersion	getVersion() Returns the Channel Access version supported by this 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.
protected void	verify(ChannelAccessVersion version, int maxPayloadSize, java.nio.charset.Charset charset) Verifies that this message can be serialized.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

ChannelAccessConnectChannelClientMessage

public ChannelAccessConnectChannelClientMessage(int cid,
                                                ChannelAccessVersion version,
                                                java.lang.String channelName)

Creates a CA_PROTO_CREATE_CHAN message. This constructor should be used to create a message that is supposed to be sent from a client to a server.

Parameters:

cid - channel CID used by the client. This is the identifier that the client will use to identify the channel in the response from the server. This number might be negative or zero. However, the value 0xffffffff is reserved for special use and should be avoided.

version - Channel Access version supported by the client.

channelName - the name of the channel that shall be connected.

Throws:

java.lang.IllegalArgumentException - if the channelCID is 0xffffffff.

Method Detail

getChannelCID

public int getChannelCID()

Returns the channel CID used by the client. This is the identifier that the client will use to identify the channel in the response from the server. This number might be negative or zero. The value 0xffffffff is reserved for special use and should be avoided. However, this value might still be used in messages sent from a client.

Returns:

channel CID assigned to the channel by the client.

getVersion

public ChannelAccessVersion getVersion()

Returns the Channel Access version supported by this client. A server can use this information in order to decide whether to reply to a search request. For example, a server might not reply to a search request if the protocol version supported by the client is too old for the server.

Returns:

Channel Access version supported by the client (never null).

getChannelName

public java.lang.String getChannelName()

Returns the name of the channel that the client wants to connect to.

Returns:

name of the channel that shall be connected. Might be null if this message instance has been reconstructed without its payload (as part of the payload of an error message).

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).

verify

protected void verify(ChannelAccessVersion version,
                      int maxPayloadSize,
                      java.nio.charset.Charset charset)

Description copied from class: ChannelAccessMessage

Verifies that this message can be serialized. This method is only intended to be used by ChannelAccessMessageCodec.

Overrides:

verify in class ChannelAccessMessage

Parameters:

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 ChannelAccessMessage

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 ChannelAccessMessage

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 ChannelAccessConnectChannelClientMessage deserialize(ChannelAccessMessageHeader messageHeader,
                                                                      ByteSource byteSource,
                                                                      boolean headerOnly,
                                                                      java.nio.charset.Charset charset)

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).

charset - encoding to use for deserializing the channel name. Usually, channel names should consist of ASCII characters only, however this is not strictly enforced by the protocol, so the encoding might matter.

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.