MQSeries::Queue -- OO interface to the MQSeries Queue objects
use MQSeries qw(:functions); use MQSeries::QueueManager; use MQSeries::Queue; use MQSeries::Message; # # Open a queue for input, loop getting messages, updating some # database with the data. # my $qmgr_obj = MQSeries::QueueManager-> new(QueueManager => 'some.queue.manager'); my $queue = MQSeries::Queue-> new(QueueManager => $qmgr_obj, Queue => 'SOME.QUEUE', Mode => 'input_exclusive', ) or die("Unable to open queue.\n"); while (1) { my $getmessage = MQSeries::Message->new(); $queue-> Get(Message => $getmessage, Sync => 1, ) or die("Unable to get message\n" . "CompCode = " . $queue->CompCode() . "\n" . "Reason = " . $queue->Reason() . "\n"); if ( UpdateSomeDatabase($getmessage->Data()) ) { $qmgr_obj->Commit() or die("Unable to commit changes to queue.\n" . "CompCode = " . $queue->CompCode() . "\n" . "Reason = " . $queue->Reason() . "\n"); } else { $qmgr_obj->Backout() or die("Unable to backout changes to queue.\n" . "CompCode = " . $queue->CompCode() . "\n" . "Reason = " . $queue->Reason() . "\n"); } } # # Put a message into the queue, using Storable to allow use of # references as message data. (NOTE: this is done for you if use the # MQSeries::Message::Storable class.) # use Storable; my $queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => 'SOME.QUEUE', Mode => 'output', PutConvert => \&Storable::nfreeze, GetConvert => \&Storable::thaw, ) or die("Unable to open queue.\n"); my $putmessage = MQSeries::Message->new ( Data => { a => [qw( b c d )], e => { f => "Huh?", g => "Wow!", }, h => 42, }, ); $queue->Put( Message => $putmessage ) or die("Unable to put message onto queue.\n" . "CompCode = " . $queue->CompCode() . "\n" . "Reason = " . $queue->Reason() . "\n"); # # Alternate mechanism for specifying the conversion routines. # my $queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => 'SOME.QUEUE', Mode => 'output', ) or die("Unable to open queue.\n"); my $putmessage = MQSeries::Message->new ( Data => { a => [qw( b c d )], e => { f => "Huh?", g => "Wow!", }, h => 42, }, ); $queue->Put(Message => $putmessage PutConvert => \&Storable::freeze, ) or die("Unable to put message onto queue.\n" . "CompCode = " . $queue->CompCode() . "\n" . "Reason = " . $queue->Reason() . "\n");
The MQSeries::Queue object is an OO mechanism for opening MQSeries Queues, and putting and getting messages from those queues, with an interface which is much simpler than the full MQI.
MQSeries::Queue
This module is used together with MQSeries::QueueManager, MQSeries::Message and MQSeries::Properties. These objects provide a subset of the MQI, with a simpler interface.
MQSeries::QueueManager
MQSeries::Message
MQSeries::Properties
The primary value added by this interface is logic to retry the connection under certain failure conditions. Basically, any Reason Code which represents a transient condition, such as a Queue Manager shutting down, or a connection lost (possible due to a network glitch?), will result in the MQCONN call being retried, after a short sleep. See below for how to tune this behavior.
This is intended to allow developers to write MQSeries applications which recover from short term outages without intervention. This behavior is critically important to the authors applications, but may not be right for yours.
The arguments to the constructor are a hash, with the following key/value pairs (required keys are marked with a '*'):
Key Value === ===== QueueManager MQSeries::QueueManager object Queue* String, or ARRAY reference (distribution list) Mode* String Options* MQOPEN 'Options' values CloseOptions MQCLOSE 'Options' values DynamicQName String DisableAutoResize Boolean AutoOpen Boolean ObjDesc HASH Reference Carp CODE Reference PutConvert CODE Reference GetConvert CODE Reference CompCode Reference to Scalar Variable Reason Reference to Scalar Variable RetrySleep Numeric RetryCount Numeric RetryReasons HASH Reference SelectionString String (MQ v7)
NOTE: Only one or the 'Options' or 'Mode' keys can be specified. They are mutually exclusive. If 'AutoOpen' is given, then both 'Options' and 'Mode' are optional, as they can be passed directly to the Open() method.
The Queue Manager to connect to must be specified, unless you want to connect to the "default" queue manager, and your site supports such a configuration.
This can either be an MQSeries::QueueManager object, or the name of the Queue Manager. Specifying the queue manager name is deprecated and will stop working in a future release.
The name of the Queue obviously must be specified. This can be either a plain ASCII string, indicating a single queue, or an ARRAY reference, indicating a distribution list. There are three ways to specify the list.
The list may be a simple array of strings:
$queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => [qw( QUEUE1 QUEUE2 QUEUE3 )], )
or, it can be an array of arrays, each one specifying the queue and queue manager name of the target queue:
$queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => [ [qw( QUEUE1 QM1 )], [qw( QUEUE2 QM2 )], [qw( QUEUE3 QM3 )], ], )
or finally, it can be an array of hash references, each naming the queue and queue manager:
$queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => [ { ObjectName => 'QUEUE1', ObjectQMgrName => 'QM1', }, { ObjectName => 'QUEUE2', ObjectQMgrName => 'QM2', }, { ObjectName => 'QUEUE3', ObjectQMgrName => 'QM3', }, ], )
In the latter two cases, the queue manager names are optional. Which method to use is largely a choice of style.
If the Mode key is specified, then the Options key may NOT be specified. These are mutually exclusive.
The Mode is a shorthand for opening the Queue for output or input, without requiring the developer to work with the Options flags directly. The mode may have one of the following values, which implies the Options shown.
Mode Value Equivalent MQOPEN Options ========== ========================= input MQOO_INPUT_AS_Q_DEF | MQOO_FAIL_IF_QUIESCING input_shared MQOO_INPUT_SHARED | MQOO_FAIL_IF_QUIESCING input_exclusive MQOO_INPUT_EXCLUSIVE | MQOO_FAIL_IF_QUIESCING output MQOO_OUTPUT | MQOO_FAIL_IF_QUIESCING
If the Options key is specified, then the Mode key may NOT be specified. These are mutually exclusive. This is a used as-is as the Options field in the MQOPEN call. Refer to the MQI documentation on MQOPEN() for more details.
This option allows you to specify the MQCLOSE() Options to be used when the perl object destructor closes the queue for you. Since there are many close options to begin with, this is primarily useful for creating Permanent Dynamic queues that you want to automatically destroy when you are finished with them.
The value specified here will be passed directly to the MQCLOSE() call, so it should be specified as:
CloseOptions => MQSeries::MQCO_DELETE_PURGE,
for example.
This is the template string to use when opening a dynamic queue. This is only relevant is the Queue specified is a model queue. Normally, this would be some kind of string ending in a '*', resulting in a unique queue name for the application.
This is a Boolean value, which if true, will disable the automatic resizing of the message buffer when it is either truncated, or the converted message will not fit.
See the Get() method documentation for more information.
This is an optional parameter that defaults to true. If the value of this argument is false, then the constructor will not implicitly call the Open() method, thus requiring the application to call it itself. This allows for more fine-grained error checking, since the constructur will then fail only if there is a problem parsing the constructor arguments. The subsequent call to Open() can be error checked independently of the new() constructor.
Open()
new()
The value of this key is a hash reference which sets the key/values of the ObjDesc structure. See the "MQSeries Application Programming Reference" documentation for the possible keys and values of the MQOD structure.
Also, see the examples section for specific usage of this feature. This is one area of the API which is not easily hidden; you have to know what you are doing.
This key specifies a code reference to a routine to replace all of the carp() calls in the API, allowing the user of the API to trap and handle all of the error message generated internally, or simply redirect how they get logged.
For example, one might want everything to be logged via syslog:
sub MyLogger { my ($message) = @_; foreach my $line (split(/\n+/, $message)) { syslog("err", $line); } }
Then, one tells the object to use this routine:
my $queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => 'SOME.QUEUE', Carp => \&MyLogger, ) or die("Unable to connect to queue manager.\n");
The default, as one might guess, is Carp::carp();
These are CODE references to subroutines which are used to convert the data in a MQSeries::Message object prior to passing it to the MQPUT MQI call, or convert the data retrieved from the queue by the MQGET MQI call before inserting it into a MQSeries::Message object.
See the MQSeries::QueueManager documentation for details on the calling and error handling syntax of these subroutines, as well as an example using Storable.pm to pass perl references around in MQSeries messages.
If this key is not specified, then the MQSeries::Queue objects will inherit these CODE references from the MQSeries::QueueManager object. If the QueueManager key was given as a name, and not an object, then no conversion is performed.
Note that these can be overridden for individual Put() or Get() calls, if necessary for a single message, just as PutConvert can be overridden for a single Put1() call (see MQSeries::QueueManager docs).
Also, note that to disable these for a single message, or a single queue, one would simply pass a function that returns its first argument.
PutConvert => sub { return $_[0]; }, GetConvert => sub { return $_[0]; },
See also the section "CONVERSION PRECEDENCE" in the MQSeries::QueueManager documentation.
When the constructor encounters an error, it returns nothing, and you can not make method calls off of a non-existent object. Thus, you do not have access to the CompCode() and Reason() method calls. If you want to extract these values, you will have to pass a scalar reference value to the constructor, for example:
my $CompCode = MQCC_FAILED; my $Reason = MQRC_UNEXPECTED_ERROR; my $queue = MQSeries::Queue->new ( QueueManager => $qmgr_obj, Queue => 'SOME,QUEUE', CompCode => \$CompCode, Reason => \$Reason, ) || die "Unable to open queue: CompCode => $CompCode, Reason => $Reason\n";
But, this is ugly (authors opinion, but then, he gets to write the docs, too).
NOTE: If you let the MQSeries::Queue object implicitly create the MQSeries::QueueManager object, and that fails, you will NOT get the CompCode/Reason values which resulted. This is intentional. If you want this level of granularity, then instantiante the MQSeries::QueueManager object yourself, and pass it to the MQSeries::Queue constructor.
See the ERROR HANDLING section as well.
The call to MQOPEN() (implemented via the Open() method), can be told to retry the failure for a specific list of reason codes. This functionality is only enabled if the RetryCount is non-zero. By default, this value is zero, and thus retries are disabled.
This argument is the amount of time, in seconds, to sleep between subsequent retry attempts.
This argument is either an ARRAY or HASH reference indicating the specific reason code for which retries will be attempted. If given as an ARRAY, the elements are simply the reason codes, and if given as a HASH, then the keys are the reason codes (and the values ignored).
This parameter is only supported if the module has been compiled with the MQ v7 libraries. It specifies the selector, which means the Get method will only return messages with matching properties. See the documentation for the MQSeries::Properties class for more details on message properties.
This method will accept the following arguments which can be passed to the constructor (new()), and it merely calls Open() to open the actual queue object.
Key Value === ===== Mode String Options MQOPEN 'Options' values RetrySleep Numeric RetryCount Numeric RetryReasons HASH Reference
This method is called automatically by the constructor, unless the AutoOpen argument is given.
AutoOpen
Note that this is a new method as of the 1.06 release, and is provided to enable more fine grained error checking. See the ERROR HANDLING section.
The arguments to this method are a hash of key/value pairs, and currently only one key is supported: "Options". The value is the Options argument to MQCLOSE(). This will override the "CloseOptions" passed to the constructor. This method merely calls MQCLOSE() to close the actual queue object.
It is important to note that normally, this method need not be called, since it is implicitly called via the object destructor. If the Close() call errors need to be handled, then it can be done explicitly. See the ERROR HANDLING section.
This method wraps the MQPUT call. The arguments are a hash, with the following key/value pairs (required keys are marked with a '*'):
Key Value === ===== Message* MQSeries::Message object PutMsgOpts HASH Reference PutMsgRecs ARRAY Reference Sync Boolean PutConvert CODE Reference Properties HASH Reference or MQSeries::Properties object
The return value is true or false, depending on the success of the underlying MQPUT() call. If the operation fails, then the Reason() and CompCode() methods will return the appropriate error codes, if the error was an MQSeries error.
If a PutConvert() method failed before the actual MQPUT() function was called, then the Reason() code will be MQRC_UNEXPECTED_ERROR, and the PutConvertReason() will be true. All of the PutConvert() methods supplied with the various MQSeries::Message subclasses in this distribution will generate some form of error via carp (or the Carp attribute of the objects, if overridden).
This argument is the message to be placed onto the queue. The value must be an MQSeries::Message object.
This option allows the programmer complete control over the PutMsgOpts structure passed to the MQPUT() call. This may conflict with the 'Sync' option; see below.
The default options specified by the OO API are
MQGMO_FAIL_IF_QUIESCING
See the MQPUT() documentation for the use of PutMsgOpts.
This argument is relevant only when using distribution lists.
The value is an ARRAY reference, specifying the put message records for the individual queues in the distribution list. Normally, these are specified as part of the PutMsgOpts, but this API attempts to hide the complexity of the PutMsgOpts structure from the user.
When using distribution lists, PutMsgRecs are often necessary to control how the MsgId, CorrelId, and three other specific fields in the MsgDesc are handled.
For details, see the MQPUT() and MQPUT1() documentation in MQSeries(3).
This is a flag to indicate that the Syncpoint option is to be used, and the message(s) not committed to the queue until an MQBACK, MQCOMM or MQDISC call is made. These are both wrapped with the queue manager Backout(), Commit() and Disconnect() methods respectively.
The value is simply interpreted as true or false.
If the Sync option is combined with the PutMsgOpts option, the Options field in the PutMsgOpts is checked for compatibility. If the Sync flag is true and the PutMsgOpts specifies MQseries::MQPMO_NO_SYNCPOINT, or vice versa, a fatal error is raised. If no conflict exists, the Sync flag amends the PutMsgOpts.
Sync
PutMsgOpts
Options
This is a means of overriding the PutConvert routine specified for the MQSeries::Queue object, for a single Put. See the new() documentation for more details.
This parameter is only supported if the module has been compiled with the MQ v7 libraries. It allows properties to be specified with the message. This can be used for selectors or for publish/subscribe.
The Properties parameter can be a hash reference or an MQSeries::Properties object. If it is a hash reference, it can be specified in two ways: as key/value pairs, or with property options.
Specifying the proeprties as key/value pairs is straightforward:
Properties => { 'perl.MQSeries.label' => 'important', 'perl.MQSeries.customer' => 'BigCompany', }
In this case, the property values are specified to MQ as strings, which is usually the correct thing to do. However, property options can be specified if so desired:
Properties => { 'perl.MQSeries.label' => 'important', 'perl.MQSeries.price' => { Type => MQSeries::MQTYPE_FLOAT64, Value => '8.99', }, 'perl.MQSeries.count' => { Type => MQSeries::MQTYPE_INT32, Value => 12, }, }
In addition to Name and Value, you can also specify Encoding and CCSID.
This method wraps the MQGET call. The arguments are a hash, with the following key/value pairs (required keys are marked with a '*'):
Key Value === ===== Message* MQSeries::Message object GetMsgOpts HASH Reference Wait Numeric Value Sync Boolean DisableAutoResize Boolean GetConvert CODE Reference Convert Boolean (default: 1)
The return value of Get() is either 1, 0 or -1. Success or failure can still be interpreted in a Boolean context, with the following caveat. A value of 1 is returned when a message was successfully retrieved from the queue. A value of 0 is returned if some form of error was encountered. A value of -1 is returned when no message was retrieved, but the MQGET call failed with a Reason Code of "MQRC_NO_MSG_AVAILABLE".
The last condition (-1) may or may not be an error, depending on your application. This merely indicates that a message matching the specified MsgDesc criteria was not found, or perhaps the queue was just empty. You have to decide how to handle this.
The return value of 0 may indicate an error in either the MQSeries call itself, or if applicable, the failure of any GetConvert() method called after a successful MQGET() call. In this case, the GetConvertReason() should be checked, as this error may indicate an invalid or improperly formatted message. This is akin to an error encountered while parsing the body of the message.
By default, the Get() method will also handle the message buffer size being too small for one very specific case.
Reason == MQRC_TRUNCATED_MSG_FAILED
In this case, the BufferLength of the Message object is reset to the DataLength value returned by the MQGET() call, and the MQGET() call is redone.
Note that this functionality can be disabled, if not desired, by specifying DisableAutoResize as an argument to either the MQSeries::Queue->new() constructor or the Get() method.
This argument is the MQSeries::Message object into which the message extracted from the queue is placed. This can be a 'raw' MQSeries::Message, or it can be one with the MsgId, or some other key in the MsgDesc explicitly specified, in order to retrieve a specific message. See MQSeries::Message documentation for more details.
This option allows the programmer complete control over the GetMsgOpts structure passed to the MQGET() call. If this option is specified, then the Sync, Wait and Convert options may modify the 'Options' field in the get-message options or raise a fatal error; see below.
Wait
Convert
MQGMO_FAIL_IF_QUIESCING MQGMO_CONVERT
See the MQGET() documentation for the use of GetMsgOpts.
This is a numeric or symbolic value, interpreted as follows. A symbolic value is a number ending on 's' for seconds or 'm' for minutes, which will be converted to the appropriate numeric value. If the value is greater than zero, then the MQGMO_WAIT option is used, and the value is set as the WaitInterval in the GetMsgOpts structure.
Remember, if a numeric value is specified, it is interpreted by the API as a number of milliseconds, not seconds (the rest of the OO-API uses seconds). Therefore, a symbolic value like "30s" or "2m" is preferred.
If the value is 0, then the MQGMO_NO_WAIT option is used.
If the value is -1, then the MQGMO_WAIT option is used, and the WaitInterval is set to MQWI_UNLIMITED, meaning the MQGET call will block until a message appears on the queue.
The default is 0, the same as the MQGET() call itself.
NOTE: MQWI_UNLIMITED should be used with caution, as applications which block forever can prevent queue managers from shutting down elegantly, in some cases.
If the Wait option is combined with the GetMsgOpts option, it will override the MQGMO_WAIT or MQGMO_NO_WAIT flag set in the GetMsgOpts.
GetMsgOpts
This is a flag to indicate that the Syncpoint option is to be used, and the message(s) not committed to the queue until an MQBACK or MQCMIT call is made. These are both wrapped with the Backout() and Commit() methods respectively.
If the Sync option is combined with the GetMsgOpts option, the Options field in the GettMsgOpts is checked for compatibility. If the Sync flag is true and the GettMsgOpts specifies MQGMO_NO_SYNCPOINT, or vice versa, a fatal error is raised. If no conflict exists, the Sync flag amends the GetMsgOpts.
GettMsgOpts
This is a flag to indicate that the conversion option is to be used. The value is simply interpreted as true or false; if omitted, the default is true.
The only reason to turn this option off is when trying to read binary messages (MQFMT_NONE) generated in a different encoding.
If the Convert option is combined with the GetMsgOpts option, it will override the MQGMO_CONVERT flag set in the GetMsgOpts.
This is a means of overriding the GetConvert routine specified for the MQSeries::Queue object, for a single Get. See the new() documentation for more details.
If the module has been compiled for MQ v7 and the queue manager connected to runs MQ v7, then the MQGET call retrieves the message proeprties by default. After the message has been read, the Properties method of the MQSeries::Message object can be called to retrieve the message properties. See the documentation of the MQSeries::Properties class for an example.
This method is an interface to the MQINQ() API call, however, it takes more convenient, human-readable strings in place of the C macros for the selectors, as well as supports more readable strings for some of the data values as well.
For example, to query the MaxMsgLength and MaxQDepth of a queue:
my %qattr = $queue->Inquire( qw(MaxMsgLength MaxQDepth) );
The argument to this method is a list of "selectors", or Queue attributes, to be queried. The following table shows the complete set of possible keys, and their underlying C macro.
Note that this list is all-inclusive, and that many of these are not supported on some of the MQSeries releases or platforms. Consult the IBM documentation for such details.
Key Macro === ===== AlterationDate MQCA_ALTERATION_DATE, AlterationTime MQCA_ALTERATION_TIME, BackoutRequeueName MQCA_BACKOUT_REQ_Q_NAME, BackoutThreshold MQIA_BACKOUT_THRESHOLD, BaseQName MQCA_BASE_Q_NAME, BaseType MQIA_BASE_TYPE, CFStructure MQCA_CF_STRUC_NAME, CLWLQueuePriority MQIA_CLWL_Q_PRIORITY, CLWLQueueRank MQIA_CLWL_Q_RANK, CLWLUseQ MQIA_CLWL_USEQ, ClusterDate MQCA_CLUSTER_DATE, ClusterName MQCA_CLUSTER_NAME, ClusterNamelist MQCA_CLUSTER_NAMELIST, ClusterQMgrName MQCA_CLUSTER_Q_MGR_NAME, ClusterQType MQIA_CLUSTER_Q_TYPE, ClusterTime MQCA_CLUSTER_TIME, CreationDate MQCA_CREATION_DATE, CreationTime MQCA_CREATION_TIME, CurrentQDepth MQIA_CURRENT_Q_DEPTH, DefBind MQIA_DEF_BIND, DefinitionType MQIA_DEFINITION_TYPE, DefInputOpenOption MQIA_DEF_INPUT_OPEN_OPTION, DefPersistence MQIA_DEF_PERSISTENCE, DefPriority MQIA_DEF_PRIORITY, DefPutResponse MQIA_DEF_PUT_RESPONSE_TYPE, DefReadAhead MQIA_DEF_READ_AHEAD, DistLists MQIA_DIST_LISTS, HardenGetBackout MQIA_HARDEN_GET_BACKOUT, HighQDepth MQIA_HIGH_Q_DEPTH, InhibitGet MQIA_INHIBIT_GET, InhibitPut MQIA_INHIBIT_PUT, InitiationQName MQCA_INITIATION_Q_NAME, MaxMsgLength MQIA_MAX_MSG_LENGTH, MaxQDepth MQIA_MAX_Q_DEPTH, MsgDeliverySequence MQIA_MSG_DELIVERY_SEQUENCE, MsgDeqCount MQIA_MSG_DEQ_COUNT, MsgEnqCount MQIA_MSG_ENQ_COUNT, NonPersistentMsgClass MQIA_NPM_CLASS, OpenInputCount MQIA_OPEN_INPUT_COUNT, OpenOutputCount MQIA_OPEN_OUTPUT_COUNT, PageSetId MQIA_PAGESET_ID, ProcessName MQCA_PROCESS_NAME, PropertyControl MQIA_PROPERTY_CONTROL, QDepthHighEvent MQIA_Q_DEPTH_HIGH_EVENT, QDepthHighLimit MQIA_Q_DEPTH_HIGH_LIMIT, QDepthLowEvent MQIA_Q_DEPTH_LOW_EVENT, QDepthLowLimit MQIA_Q_DEPTH_LOW_LIMIT, QDepthMaxEvent MQIA_Q_DEPTH_MAX_EVENT, QDesc MQCA_Q_DESC, QMgrIdentifier MQCA_Q_MGR_IDENTIFIER, QName MQCA_Q_NAME, QNames MQCACF_Q_NAMES, QueueAccounting MQIA_ACCOUNTING_Q, QueueMonitoring MQIA_MONITORING_Q, QueueStatistics MQIA_STATISTICS_Q, QServiceInterval MQIA_Q_SERVICE_INTERVAL, QServiceIntervalEvent MQIA_Q_SERVICE_INTERVAL_EVENT, QType MQIA_Q_TYPE, RemoteQMgrName MQCA_REMOTE_Q_MGR_NAME, RemoteQName MQCA_REMOTE_Q_NAME, RetentionInterval MQIA_RETENTION_INTERVAL, Scope MQIA_SCOPE, Shareability MQIA_SHAREABILITY, StorageClass MQCA_STORAGE_CLASS, TimeSinceReset MQIA_TIME_SINCE_RESET, TPipeNames MQCA_TPIPE_NAME, TriggerControl MQIA_TRIGGER_CONTROL, TriggerData MQCA_TRIGGER_DATA, TriggerDepth MQIA_TRIGGER_DEPTH, TriggerMsgPriority MQIA_TRIGGER_MSG_PRIORITY, TriggerType MQIA_TRIGGER_TYPE, Usage MQIA_USAGE, XmitQName MQCA_XMIT_Q_NAME,
The return value of this method is a hash, whose keys are those given as arguments, and whose values are the queried queue attributes. In most cases, the values are left unmolested, but in the following cases, the values are mapped to more readable strings.
Key Macro === ===== OnOpen MQBND_BIND_ON_OPEN NotFixed MQBND_BIND_NOT_FIXED
Key Macro === ===== Permanent MQQDT_PERMANENT_DYNAMIC Temporary MQQDT_TEMPORARY_DYNAMIC
Key Macro === ===== Exclusive MQOO_INPUT_EXCLUSIVE Shared MQOO_INPUT_SHARED
Key Macro === ===== FIFO MQMDS_FIFO Priority MQMDS_PRIORITY
Key Macro === ===== High MQQSIE_HIGH None MQQSIE_NONE OK MQQSIE_OK
Key Macro === ===== Alias MQQT_ALIAS All MQQT_ALL Cluster MQQT_CLUSTER Local MQQT_LOCAL Model MQQT_MODEL Remote MQQT_REMOTE
Key Macro === ===== Cell MQSCO_CELL QMgr MQSCO_Q_MGR
Key Macro === ===== Depth MQTT_DEPTH Every MQTT_EVERY First MQTT_FIRST None MQTT_NONE
Key Macro === ===== Normal MQUS_NORMAL XMITQ MQUS_TRANSMISSION
This method is an interface to the MQSET() API call, and like Inquire(), it takes more convenient, human-readable strings in place of the C macros.
For example, to put inhibit a queue:
$queue->Set( InhibitPut => 1 );
The argument to this method is a hash of key/value pairs representing queue attributes to be set. The MQSET() API supports setting a very limited subset of specific queue attributes. The following table shows the complete set of possible keys, and their underlying C macros.
Key Macro === ===== InhibitGet MQIA_INHIBIT_GET InhibitPut MQIA_INHIBIT_PUT DistLists MQIA_DIST_LISTS TriggerControl MQIA_TRIGGER_CONTROL TriggerData MQCA_TRIGGER_DATA TriggerDepth MQIA_TRIGGER_DEPTH TriggerMsgPriority MQIA_TRIGGER_MSG_PRIORITY TriggerType MQIA_TRIGGER_TYPE
In addition, the data value for the "TriggerType" key can have one of the following values:
All of the other values are simply Boolean (0 or 1), with the exception of "TriggerData", which is a string.
This method call returns true upon success, and false upon failure. CompCode() and Reason() will be set appropriately.
This method can be used to query the ObjDesc data structure. If no argument is given, then the ObjDesc hash reference is returned. If a single argument is given, then this is interpreted as a specific key, and the value of that key in the ObjDesc hash is returned.
This method takes no arguments, and returns the MQSeries::QueueManager object used by the queue.
This method returns the MQI Completion Code for the most recent MQI call attempted.
This method returns the MQI Reason Code for the most recent MQI call attempted.
This method returns a true of false value, indicating if a PutConvert method failed or not. Similar to the MQRC reason codes, false indicates success, and true indicates some form of error. If there was no PutConvert method called, this will always return false.
This method returns a true of false value, indicating if a GetConvert method failed or not. Similar to the MQRC reason codes, false indicates success, and true indicates some form of error. If there was no GetConvert method called, this will always return false.
This method call returns an array reference, and each member of the array is a Response Record returned as a possible side effect of calling a Put() method to put a message to a distribution list.
The individual records are hash references, with two keys: CompCode and Reason. Each provides the specific CompCode and Reason associated with the put of the message to each individual queue in the distribution list, respectively.
Normally, when MQOPEN() fails, the method that called it (Open() or new()) also fails. It is possible to have the Open() method retry the MQOPEN() call for a specific set of reason codes.
By default, the retry logic is disabled, but it can be enabled by setting the RetryCount to a non-zero value. The list of reason codes defaults to just MQRC_OBJECT_IN_USE, but a list of retryable codes can be specified via the RetryReasons argument.
You are probably wondering why this logic is useful for MQOPEN(). The choice of the default RetryReasons is not without its own reason.
Consider an application that opens a queue for exclusive input. If that application crashes and restarts, there will typically be a window of time when the queue manager has not yet noticed that the crashed application instance has died. The application which has been restarted will not fail to open the queue, and MQOPEN() will set the reason to MQRC_OBJECT_IN_USE.
By retrying this particular reason code, and tuning the RetryCount and RetrySleep to be consistent with the timeout on the queue manager, applications can restart, reconnect and reopen these queues transparently.
There are almost certainly other scenarios where the RetryReasons may need to be customized, and thus the code supports this flexibility.
Most methods return a true or false value indicating success of failure, and internally, they will call the Carp subroutine (either Carp::carp(), or something user-defined) with a text message indicating the cause of the failure.
In addition, the most recent MQI Completion and Reason codes will be available via the CompCode() and Reason() methods:
$queue->CompCode() $queue->Reason()
When distribution lists are used, then it is possible for a list of reason codes to be returned by the API. Normally, these are buried inside the ObjDesc strucure, but they are also available via the
$queue->Reasons()
method. In this case, the $queue->Reason() will always return MQRC_MULTIPLE_REASONS. The return value of the Reasons() method is an array reference, and each array item is a hash reference with two keys: CompCode and Reason. These correspond, respectively, with the CompCode and Reason associated with the individual queues in the distribution list.
For example, the Reason code associated with the 3rd queue in the list would be:
$queue->Reasons()->[2]->{Reason}
In the case of the constructor new(), which returns nothing when it fails, these methods are not available. Most applications will not need to handle the specific CompCode and Reason when the instantiation fails, but if necessary, these can be obtained in one of two ways.
The older method, which is supported for backwards compabitility but strongly discouarged, is to pass references to scalar variables to new(). See the new() documentation above for more details.
The newer method would be to explicitly call the Open() method, and error check it yourself. This will mean that the constructor will now fail only if there is an error processing the constructor arguments, as opposed to an error in the MQSeries infrastructure.
Some examples should make this clear.
The simplest way to create an MQSeries::Queue object is:
my $queue = MQSeries::Queue->new ( QueueManager => 'some.queue.manager', Queue => 'SOME.QUEUE', Mode => 'input', ) || die;
But in this case, either the connection to the queue manager or the open of the queue could fail, and your application will not be able to determine why.
In order to explicitly have access to the CompCode and Reason one would do the following:
# Explicitly create your own MQSeries::QueueManager object my $qmgr = MQSeries::QueueManager->new ( QueueManager => 'some.queue.manager', AutoConnect => 0, ) || die "Unable to instantiate MQSeries::QueueManager object\n"; # Call the Connect method explicitly unless ( $qmgr->Connect() ) { die("Connection to queue manager failed\n" . "CompCode => " . $qmgr->CompCode() . "\n" . "Reason => " . $qmgr->Reason() . "\n"); } my $queue = MQSeries::Queue->new ( QueueManager => $qmgr, Queue => 'SOME.QUEUE', Mode => 'input', AutoOpen => 0, ) || die "Unable to instantiate MQSeries::Queue object\n"; # Call the Open method explicitly unless ( $queue->Open() ) { die("Open of queue failed\n" . "CompCode => " . $queue->CompCode() . "\n" . "Reason => " . $queue->Reason() . "\n"); }
MQSeries(3), MQSeries::QueueManager(3), MQSeries::Message(3), MQSeries::Properties(3)
To install MQSeries, copy and paste the appropriate command in to your terminal.
cpanm
cpanm MQSeries
CPAN shell
perl -MCPAN -e shell install MQSeries
For more information on module installation, please visit the detailed CPAN module installation guide.