com.aquenos.epics.jackie.common.protocol

Class ChannelAccessWriteNotifyClientMessage

java.lang.Object

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

com.aquenos.epics.jackie.common.protocol.ChannelAccessWriteNotifyMessage

com.aquenos.epics.jackie.common.protocol.ChannelAccessWriteNotifyClientMessage

public final class ChannelAccessWriteNotifyClientMessage
extends ChannelAccessWriteNotifyMessage

Representation of a CA_PROTO_WRITE_NOTIFY message that is sent from a client to a server. This message is sent in order to write to a channel and get a response when the write operation has finished.

Author:

Sebastian Marsching

See Also:

ChannelAccessCommand.CA_PROTO_WRITE_NOTIFY, ChannelAccessWriteNotifyMessage, ChannelAccessWriteNotifyServerMessage

Field Summary

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

command, originalMessageHeader

Constructor Summary

Constructors

Constructor and Description
ChannelAccessWriteNotifyClientMessage(ChannelAccessValueType dataType, int count, int sid, int operationId, ChannelAccessPuttableValue<?> value) Creates a CA_PROTO_WRITE_NOTIFY message.

Method Summary

Modifier and Type	Method and Description
protected static ChannelAccessWriteNotifyClientMessage	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	getChannelSID() Returns the channel SID.
int	getCount() Returns the number of elements the value in this message's payload has.
ChannelAccessValueType	getDataType() Returns the data type of the value in this message's payload.
int	getOperationId() Returns the client-assigned operation ID.
ChannelAccessPuttableValue<?>	getValue() Returns the new value for the channel.
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

ChannelAccessWriteNotifyClientMessage

public ChannelAccessWriteNotifyClientMessage(ChannelAccessValueType dataType,
                                             int count,
                                             int sid,
                                             int operationId,
                                             ChannelAccessPuttableValue<?> value)

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

Parameters:

dataType - data type of the value in the message's payload (never null). This must match the type of value.

count - number of value elements in the message's payload. This must not be negative and not exceed the number of elements in value.

sid - server-assigned ID identifying the channel.

operationId - client-assigned ID identifying the write request. This ID will be sent with the reply so that the client can identify the request to which the reply belongs.

value - new value of the channel (never null).

Throws:

java.lang.IllegalArgumentException - if the specified data type does not match the value's data type or if count is negative or greater than the number of elements the value has.

Method Detail

getDataType

public ChannelAccessValueType getDataType()

Returns the data type of the value in this message's payload. Returns null if the specified data-type is unknown to this implementation.

Returns:

data-type of the value or null if the numeric identifier cannot be mapped to a data type known by this implementation.

getCount

public int getCount()

Returns the number of elements the value in this message's payload has.

Returns:

number of value elements.

getChannelSID

public int getChannelSID()

Returns the channel SID. This is the identifier that the server uses to identify the channel. This number might be negative or zero.

Returns:

channel SID assigned to the channel by the server.

getOperationId

public int getOperationId()

Returns the client-assigned operation ID. The operation ID is used by the client in order to map the reply to this message to the original read request. This number might be negative or zero.

Returns:

client-assigned operation identifier.

getValue

public ChannelAccessPuttableValue<?> getValue()

Returns the new value for the channel. This method returns null if the data-type sent by the client is not supported by this implementation (getDataType() returns null).

Returns:

new value for the channel or null if the data type is not supported. The value's data type is the same that is returned by getDataType() and the value's element count is equal to or greater than the number returned by getCount().

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 ChannelAccessWriteNotifyClientMessage 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 host name. Usually, host 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 (if headerOnly is false).

Throws:

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

ShortPayloadException - if the message's payload size is less than the size needed for the data type and count.