com.guardtime.ksi.pdu

Class PduMessageHeader

java.lang.Object

com.guardtime.ksi.tlv.TLVStructure

com.guardtime.ksi.pdu.PduMessageHeader

public class PduMessageHeader
extends TLVStructure

Message header TLV object. The message header consist of the following fields:

• login identifier - identifier of the client host for MAC key lookup by server
• instance identifier - a number identifying invocation of the sender
• message identifier - message number for duplicate filtering

 TLV [01] header {
   TLV [01] login_id { utf8 string }
   TLV [02] inst_id { integer } // optional
   TLV [03] msg_id { integer } // optional
 }
 

The instance and message identifier fields, when present, are used for filtering duplicate messages. The value of the `instance identifier' field should increase every time the sending process is restarted. The `message identifier' should sequentially number the messages within a process invocation. Having seen messages with a higher `instance identifier' value from a client, a server may drop future messages with lower `instance identifier' values assuming these are delayed messages from a previous invocation and thus no longer relevant. Similarly, a server may prioritize messages from a given client invocation by `message identifier' values under the assumption that messages with lower values are more likely to be stale.

Messages where the `instance identifier' and `message identifier' fields are absent should be considered unique. This is to accommodate short-lived client applications that typically send only a single request; for long-lived processes the `instance identifier' and `message identifier' fields should be considered mandatory.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ELEMENT_TYPE_MESSAGE_HEADER

Fields inherited from class com.guardtime.ksi.tlv.TLVStructure

rootElement

Constructor Summary

Constructors

Constructor and Description
PduMessageHeader(String loginId) Constructor for creating a new message header object with client identifier.
PduMessageHeader(String loginId, KSIRequestContext context) Constructor for creating a new message header object with given KSIRequestContext.
PduMessageHeader(String loginId, Long instanceId, Long messageId) Constructor for creating a new message header object with client, instance and message identifier.
PduMessageHeader(TLVElement rootElement) Creates new message header object from base TLV element.

Method Summary

Modifier and Type	Method and Description
int	getElementType()
Long	getInstanceId()
String	getLoginId()
Long	getMessageId()

Methods inherited from class com.guardtime.ksi.tlv.TLVStructure

equals, getRootElement, hashCode, readOnce, verifyCriticalFlag, writeTo

Methods inherited from class java.lang.Object

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

Field Detail

ELEMENT_TYPE_MESSAGE_HEADER

public static final int ELEMENT_TYPE_MESSAGE_HEADER

See Also:

Constant Field Values

Constructor Detail

PduMessageHeader

public PduMessageHeader(String loginId)
                 throws KSIException

Constructor for creating a new message header object with client identifier. Should be used by short-lived client applications that typically send only a single request; for long-lived processes the `instance identifier' and `message identifier' fields should be considered mandatory.

Parameters:

loginId - identifier of the client host for MAC key lookup.

Throws:

KSIException

PduMessageHeader

public PduMessageHeader(String loginId,
                        Long instanceId,
                        Long messageId)
                 throws KSIException

Constructor for creating a new message header object with client, instance and message identifier.

Parameters:

loginId - identifier of the client host for MAC key lookup.

instanceId - a number identifying invocation of the sender; can not be null when message identifier is present.

messageId - message number for duplicate filtering; can not be null when instance identifier is present.

Throws:

KSIException

PduMessageHeader

public PduMessageHeader(String loginId,
                        KSIRequestContext context)
                 throws KSIException

Constructor for creating a new message header object with given KSIRequestContext.

Throws:

KSIException

PduMessageHeader

public PduMessageHeader(TLVElement rootElement)
                 throws KSIException

Creates new message header object from base TLV element.

Parameters:

rootElement - instance ofTLVElement.

Throws:

KSIException

Method Detail

getInstanceId

public Long getInstanceId()

Returns:

The number identifying invocation of the sender; can not be null when message identifier is present.

getMessageId

public Long getMessageId()

Returns:

The message number for duplicate filtering; can not be null when instance identifier is present.

getLoginId

public String getLoginId()

Returns:

The identifier of the client host for MAC key lookup.

getElementType

public int getElementType()

Specified by:

getElementType in class TLVStructure