MQMD

java.lang.Object
- com.ibm.mq.jmqi.JmqiObject
- - com.ibm.mq.MQMD

Direct Known Subclasses:

MQMessage
```
public class MQMD
extends com.ibm.mq.jmqi.JmqiObject
```
The MQMD class contains the control information that accompanies the application data when a message travels between the sending and receiving applications.
Character data in the message descriptor is in the character set of the queue manager to which the application is connected; this is given by the CodedCharSetId queue manager attribute. Numeric data in the message descriptor is in the native machine encoding (given by MQENC_NATIVE).

If the sending and receiving queue managers use different character sets or encodings, the data in the message descriptor is converted automatically - it is not necessary for the receiving application to perform these conversions.

You can write an exit to convert an application's message data, that will be invoked when an MQGET call retrieves the message.

See Also:

MQMessage

Field Summary

Fields
Modifier and Type	Field and Description
`byte[]`	`accountingToken` The accounting token.
`java.lang.String`	`applicationIdData` Application ID data.
`java.lang.String`	`applicationOriginData` Data about the originating application.
`int`	`backoutCount` The number of times the message has been backed out.
`int`	`characterSet` The coded character set identifier of character data in the application message data.
`byte[]`	`correlationId` Specifies the correlation identifier of the message to be retrieved.
`int`	`encoding` Specifies the representation used for numeric values in the application message data.
`int`	`expiry` The expiry time (in tenths of a second).
`int`	`feedback` The nature of the feedback report.
`java.lang.String`	`format` A name which indicates the nature of the data in the message.
`byte[]`	`groupId` The ID of the message group.
`int`	`messageFlags` Flags controlling the segmentation and status of the message.
`byte[]`	`messageId` Specifies the message identifier of the message to be retrieved.
`int`	`messageSequenceNumber` Sequence number of logical message within group.
`int`	`messageType` Indicates the type of the message.
`int`	`offset` Offset of data in the physical message from the start of the logical message.
`int`	`originalLength` Original length of a segmented message.
`int`	`persistence` The message persistence.
`int`	`priority` The message priority.
`java.lang.String`	`putApplicationName` The name of the application that put the message.
`int`	`putApplicationType` The type of application that put the message.
`java.util.GregorianCalendar`	`putDateTime` The time and date when the message was put.
`java.lang.String`	`replyToQueueManagerName` The name of the queue manager to which reply or report messages should be sent.
`java.lang.String`	`replyToQueueName` The name of the queue to which a reply should be sent.
`int`	`report` This field enables the application sending the original message to specify which report messages are required, whether the application message data is to be included in them, and also how the message and correlation ID in the report or reply are to be set.
`java.nio.charset.CodingErrorAction`	`unmappableAction` The action to be taken if character data cannot be encoded using the character set specified The default value for this field is taken from system Java MQI, which can be configured via the Java system property: com.ibm.mq.cfg.jmqi.UnmappableCharacterAction The default Java MQI system value is used when the above Java system property has not been configured on the Java Runtime Environment and is java.nio.charset.CodingErrorAction.REPORT.
`byte[]`	`unMappableReplacement` The byte sequence to be used if character data cannot be encoded using the character set specified and the unmappableAction is java.nio.charset.CodingErrorAction.REPLACE.
`java.lang.String`	`userId` The user ID.

Fields inherited from class com.ibm.mq.jmqi.JmqiObject
COMP_JM, COMP_JN, COMP_JO

Constructor Summary

Constructors
Constructor and Description

MQMD()
The default constructor.

Constructors
Constructor and Description
`MQMD()` The default constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`getVersion()` Gets the version of the message.
`void`	`setVersion(int version)` Sets the version of the message.

Methods inherited from class com.ibm.mq.jmqi.JmqiObject
getJmqiEnvironment

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

report

public int report

This field enables the application sending the original message to specify which report messages are required, whether the application message data is to be included in them, and also how the message and correlation ID in the report or reply are to be set. It comprises one or more constants from the CMQC class combined by means of the '+' or '|' operators.
You can select one type from each row of the following table:

	basic	with data	with full data
Exception	`CMQC.MQRO_EXCEPTION`	`CMQC.MQRO_EXCEPTION_WITH_DATA`	`CMQC.MQRO_EXCEPTION_WITH_FULL_DATA`
Expiration	`CMQC.MQRO_EXPIRATION`	`CMQC.MQRO_EXPIRATION_WITH_DATA`	`CMQC.MQRO_EXPIRATION_WITH_FULL_DATA`
Confirm on arrival	`CMQC.MQRO_COA`	`CMQC.MQRO_COA_WITH_DATA`	`CMQC.MQRO_COA_WITH_FULL_DATA`
Confirm on delivery	`CMQC.MQRO_COD`	`CMQC.MQRO_COD_WITH_DATA`	`CMQC.MQRO_COD_WITH_FULL_DATA`

You can specify how the message ID is generated for the report or reply message:

You can specify one of the following to control how to set the correlation ID of the report or reply message:

You can specify the following to pass the discard option and exiry time of the original message to the report or reply message:

CMQC.MQRO_PASS_DISCARD_AND_EXPIRY

You can specify one of the following to control the disposition of the original message when it cannot be deleivered to the destination queue:

If no report options are specified, the default is
CMQC.MQRO_NEW_MSG_ID | CMQC.MQRO_COPY_MSG_ID_TO_CORREL_ID | CMQC.MQRO_DEAD_LETTER_Q.

messageType
```
public int messageType
```
Indicates the type of the message. The following values are currently defined:
Application defined values can also be used; these should be in the range MQMT_APPL_FIRSTto MQMT_APPL_LAST.

The default value of this field is CMQC.MQMT_DATAGRAM.

expiry
```
public int expiry
```
The expiry time (in tenths of a second). It is set by the application which puts the message. After a message's expiry time has elapsed, it is eligible to be discarded by the queue manager. If the message specified one of the CMQC.MQRO_EXPIRATIONflags, then a report is generated when the message is discarded.
The default value is CMQC.MQEI_UNLIMITED, which means that the message never expires.

feedback
```
public int feedback
```
The nature of the feedback report. It is used with a message of type CMQC.MQMT_REPORTto indicate the nature of the report.
The following feedback codes are defined:
Application-defined feedback values in the range CMQC.MQFB_APPL_FIRSTto CMQC.MQFB_APPL_LASTcan also be used.

The default value of this field is CMQC.MQFB_NONE, indicating that no feedback is provided.

encoding

public int encoding

Specifies the representation used for numeric values in the application message data. This applies to binary, packed decimal and floating point data. The behaviour of the read and write methods for these numeric formats is altered accordingly.

The following encodings are defined:

	binary	packed decimal	floating point
big-endian	`CMQC.MQENC_INTEGER_NORMAL`	`CMQC.MQENC_DECIMAL_NORMAL`	`CMQC.MQENC_FLOAT_IEEE_NORMAL`
little-endian	`CMQC.MQENC_INTEGER_REVERSED`	`CMQC.MQENC_DECIMAL_REVERSED`	`CMQC.MQENC_FLOAT_IEEE_REVERSED`
zSeries	`CMQC.MQENC_INTEGER_NORMAL`	`MQENC_DECIMAL_NORMAL`	`CMQC.MQENC_FLOAT_S390`

Construct a value for the encoding field by combining one value from each row of the table by use of '+' or '|' operators. The default value is CMQC.MQENC_INTEGER_NORMAL | CMQC.MQENC_DECIMAL_NORMAL | CMQC.MQENC_FLOAT_IEEE_NORMAL. For convenience this value is also represented by CMQC.MQENC_NATIVE. This setting causes MQMessage.writeInt()to write, for example, a big-endian integer, and MQMessage.readInt()to read a big-endian integer.

A loss in precision can occur when converting from IEEE format floating point values to zSeries format floating point values.

characterSet
```
public int characterSet
```
The coded character set identifier of character data in the application message data. It alters the behaviour of MQMessage.readString(), MQMessage.readLine()and MQMessage.writeString().
The default value for this field is CMQC.MQCCSI_Q_MGR. The following additional character set values are supported:

850
commonly used ASCII codeset
819
the ISO standard ASCII codeset
37
the American EBCDIC codeset
1200
Unicode
1208
UTF-8

unmappableAction
```
public java.nio.charset.CodingErrorAction unmappableAction
```
The action to be taken if character data cannot be encoded using the character set specified
The default value for this field is taken from system Java MQI, which can be configured via the Java system property: com.ibm.mq.cfg.jmqi.UnmappableCharacterAction The default Java MQI system value is used when the above Java system property has not been configured on the Java Runtime Environment and is java.nio.charset.CodingErrorAction.REPORT. Other java.nio.charset.CodingErrorAction constants are valid values.

unMappableReplacement
```
public byte[] unMappableReplacement
```
The byte sequence to be used if character data cannot be encoded using the character set specified and the unmappableAction is java.nio.charset.CodingErrorAction.REPLACE.
The default value for this field is taken from system Java MQI, which can be configured via the Java system property: com.ibm.mq.cfg.jmqi.UnmappableCharacterReplacement The default Java MQI system value is used when the above Java system property has not been configured on the Java Runtime Environment and is the UTF-8 representation of '?'.
The default Java replacement String will be used in decoding operations.

format
```
public java.lang.String format
```
A name which indicates the nature of the data in the message. It is set by the sender. You can use your own format names, but names beginning with the letters "MQ" have meanings that are defined by the queue manager.
The queue manager built-in formats are:
The default value is CMQC.MQFMT_NONE.

priority
```
public int priority
```
The message priority.
The default value is CMQC.MQPRI_PRIORITY_AS_Q_DEF.

persistence
```
public int persistence
```
The message persistence. The following values are defined:
The default value is CMQC.MQPER_PERSISTENCE_AS_Q_DEF

messageId
```
public byte[] messageId
```
Specifies the message identifier of the message to be retrieved. This applies to MQQueue.get(). Normally the queue manager returns the first message whose message identifier and correlation identifier match those specified. The special value CMQC.MQMI_NONE allows any message identifier to match.
For MQQueue.put()this specifies the message identifier to use. If CMQC.MQMI_NONE is specified, the queue manager generates a unique message identifier when the message is put. The value of this field is updated after the put to indicate the message identifier that was used.

The default value is CMQC.MQMI_NONE.

correlationId
```
public byte[] correlationId
```
Specifies the correlation identifier of the message to be retrieved. This applies to MQQueue.get(). Normally the queue manager returns the first message whose message identifier and correlation identifier match those specified. The special value CMQC.MQCI_NONE allows any correlation identifier to match.
For MQQueue.put()this specifies the correlation identifier to use.

The default value is CMQC.MQCI_NONE.

backoutCount
```
public int backoutCount
```
The number of times the message has been backed out. This is the number of times the message has been returned by MQQueue.get(), as part of a unit of work, and subsequently backed out.
The default value is zero.

replyToQueueName
```
public java.lang.String replyToQueueName
```
The name of the queue to which a reply should be sent. The application that issued the get request for the message should send CMQC.MQFMT_REPLY and CMQC.MQFMT_REPORT messages to this queue.
The default value is "" (empty string).

replyToQueueManagerName
```
public java.lang.String replyToQueueManagerName
```
The name of the queue manager to which reply or report messages should be sent.
The default value is "" (empty string).

userId
```
public java.lang.String userId
```
The user ID. It is part of the identity of the message and identifies which user originated it.
The default value is "" (empty string).

accountingToken
```
public byte[] accountingToken
```
The accounting token. This is part of the identity of the message and it allows work done as a result of the message to be appropriately charged.
The default value is an array of zeros.

applicationIdData
```
public java.lang.String applicationIdData
```
Application ID data. This is part of the identity context of the message - information defined by the application suite; it can be used to provide additional information about the message or its originator.
The default value is "" (empty string).

putApplicationType
```
public int putApplicationType
```
The type of application that put the message. The value can be defined by the system or by the user.
The following values are defined by the system:
- MQC.MQAT_AIX
- MQC.MQAT_CICS
- MQC.MQAT_DOS
- MQC.MQAT_IMS
- MQC.MQAT_MVS
- MQC.MQAT_OS2
- MQC.MQAT_OS400
- MQC.MQAT_QMGR
- MQC.MQAT_UNIX
- MQC.MQAT_WINDOWS
- MQC.MQAT_JAVA
- MQC.MQAT_UNKNOWN
- MQC.MQAT_NO_CONTEXT
- MQC.MQAT_CICS_VSE
- MQC.MQAT_VMS
- MQC.MQAT_GUARDIAN
- MQC.MQAT_VOS
- MQC.MQAT_DEFAULT
- MQC.MQAT_NSK
- MQC.MQAT_CICS_BRIDGE
- MQC.MQAT_NOTES_AGENT
- MQC.MQAT_WINDOWS_NT
- MQC.MQAT_IMS_BRIDGE
- MQC.MQAT_XCF
The default value is the special value CMQC.MQAT_NO_CONTEXT, which indicates that no context information is present in the message.

putApplicationName
```
public java.lang.String putApplicationName
```
The name of the application that put the message.
The default value is "" (empty string).

putDateTime
```
public java.util.GregorianCalendar putDateTime
```
The time and date when the message was put.

applicationOriginData
```
public java.lang.String applicationOriginData
```
Data about the originating application. This can be used by the application to provide additional information about the origin of the message.
The default value is "" (empty string).

groupId
```
public byte[] groupId
```
The ID of the message group. This identifies the message group to which the message belongs.

messageSequenceNumber
```
public int messageSequenceNumber
```
Sequence number of logical message within group.

offset
```
public int offset
```
Offset of data in the physical message from the start of the logical message.

messageFlags
```
public int messageFlags
```
Flags controlling the segmentation and status of the message. Possible values are:

originalLength
```
public int originalLength
```
Original length of a segmented message.

Constructor Detail
- MQMD
```
public MQMD()
```
  The default constructor.

Method Detail
- getVersion
```
public int getVersion()
```
  Gets the version of the message.
  
  Returns:
  
  the version.
- setVersion
```
public void setVersion(int version)
                throws MQException
```
  Sets the version of the message.
  Parameters:
  version - the value to be set - valid values are
  - com.ibm.mq.constants.CMQC.MQMD_VERSION_1
  - com.ibm.mq.constants.CMQC.MQMD_VERSION_2
  Throws:
  
  MQException - if the value of the version is invalid.

Fields inherited from class com.ibm.mq.jmqi.JmqiObject

Methods inherited from class com.ibm.mq.jmqi.JmqiObject

Methods inherited from class java.lang.Object

report

messageType

expiry

feedback

encoding

characterSet

unmappableAction

unMappableReplacement

format

priority

persistence

messageId

correlationId

backoutCount

replyToQueueName

replyToQueueManagerName

userId

accountingToken

applicationIdData

putApplicationType

putApplicationName

putDateTime

applicationOriginData

groupId

messageSequenceNumber

offset

messageFlags

originalLength

MQMD

getVersion

setVersion