NAME

Net::Z3950::APDU - Read-only objects representing decoded Z39.50 APDUs


SYNOPSIS

You probably shouldn't be reading this!

        package Net::Z3950::APDU::SomeSpecificSortOfAPDU;
        use Net::Z3950::APDU;
        @ISA = qw(Net::Z3950::APDU);
        @FIELDS = qw(names of APDU fields);


DESCRIPTION

This class provides a trivial base for the various read-only APDUs implemented as a part of the Net::Z3950 module. Its role is simply to supply named methods providing read-only access to the same-named fields. The set of fields is specified by the derived class's package-global @FIELDS array.

You don't need to understand or use this class in order to use the Net::Z3950 module. It's purely an implementation detail. In fact, I probably should never even have written this documentation. Forget I said anything. Go and read the next section.


SUBCLASSES

The following classes are all trivial derivations of Net::Z3950::APDU, and represent specific types of APDU. Each such class is characterised by the set of data-access methods it supplies: these are listed below.

Each method takes no arguments, and returns the information implied by its name. See the relevant sections of the Z39.50 Standard for information on the interpretation of this information - for example, section 3.2.1 (Initialization Facility) describes the elements of the Net::Z3950::APDU::InitResponse class.

Actually, you don't need to understand or use any of these classes either: they're used internally in the implementation, so this documentation is provided as a service to those who will further develop this module in the future.

Net::Z3950::APDU::InitResponse

        referenceId()
        preferredMessageSize()
        maximumRecordSize()
        result()
        implementationId()
        implementationName()
        implementationVersion()

Net::Z3950::APDU::SearchResponse

        referenceId()
        resultCount()
        numberOfRecordsReturned()
        nextResultSetPosition()
        searchStatus()
        resultSetStatus()
        presentStatus()
        records()
        additionalSearchInfo()

Net::Z3950::APDU::ScanResponse

        referenceId()
        stepSize()
        scanStatus()
        numberOfEntriesReturned()
        positionOfTerm()
        entries()
        diag()

The diag() method should be consulted when scanStatus() returns 6, indicating failure; otherwise, entries() may be consulted.

Net::Z3950::APDU::PresentResponse

        referenceId()
        numberOfRecordsReturned()
        nextResultSetPosition()
        presentStatus()
        records()

Net::Z3950::APDU::DeleteRSResponse

        referenceId()
        deleteOperationStatus()

(We don't bother to decode the rest of this APDU at the moment, since I bet everyone calls Net::Z3950::ResultSet::delete() in void context. If anyone wants more information out of it, we can wire it through.)

Net::Z3950::APDU::Close

        referenceId()
        closeReason()
        diagnosticInformation()

In addition, this class provides a method of no arguments, as_text(), which returns a human-readable string describing the reason for the close.

Net::Z3950::APDU::NamePlusRecordList

No methods - just treat as a reference to an array of Net::Z3950::APDU::NamePlusRecord

Net::Z3950::APDU::NamePlusRecord

        databaseName()
        which()
        databaseRecord()
        surrogateDiagnostic()
        startingFragment()
        intermediateFragment()
        finalFragment()

Only one of the last five methods will return anything - you can find out which one by inspecting the return value of the which() method, which always takes one of the following values:

When which() is Net::Z3950::NamePlusRecord::DatabaseRecord, the object returned from the databaseRecord() method will be a decoded Z39.50 EXTERNAL. Its type may be any of the following (and may be tested using $rec->isa('Net::Z3950::Record::Whatever') if necessary.)

Net::Z3950::APDU::SUTRS, Net::Z3950::APDU::USMARC, Net::Z3950::APDU::UKMARC, Net::Z3950::APDU::NORMARC, Net::Z3950::APDU::LIBRISMARC, Net::Z3950::APDU::DANMARC, Net::Z3950::APDU::UNIMARC, Net::Z3950::APDU::MAB

No methods - just treat as an opaque chunk of data.

Net::Z3950::APDU::TaggedElement;

        tagType()
        tagValue()
        tagOccurrence()
        content()

Net::Z3950::APDU::ElementData

        which()
        numeric()
        string()
        oid()
        subtree()

Only one of the last four methods will return anything - you can find out which one by inspecting the return value of the which() method, which always takes one of the following values:

Net::Z3950::APDU::HoldingsData

No methods - just treat as a reference to an array of objects, where each object is either an MARC holdings record (of type Net::Z3950::Record::USMARC or similar) or a Net::Z3950::APDU::HoldingsAndCirc

Net::Z3950::APDU::HoldingsAndCirc

        typeOfRecord()
        encodingLevel()
        format()
        receiptAcqStatus()
        generalRetention()
        completeness()
        dateOfReport()
        nucCode()
        localLocation()
        shelvingLocation()
        callNumber()
        shelvingData()
        copyNumber()
        publicNote()
        reproductionNote()
        termsUseRepro()
        enumAndChron()
        volumes()
        circulationData()

All but the last two of these have string values, although not necessarily human-readable strings. volumes() returns a Net::Z3950::APDU::Volumes object (note the plural in the type-name), and circulationData() a Net::Z3950::APDU::CirculationData.

Net::Z3950::APDU::Volumes

No methods - just treat as a reference to an array of Net::Z3950::APDU::Volume objects.

Net::Z3950::APDU::HoldingsAndCirc

        enumeration()
        chronology()
        enumAndChron()

Net::Z3950::APDU::CirculationData

No methods - just treat as a reference to an array of Net::Z3950::APDU::CircRecord objects.

Net::Z3950::APDU::HoldingsAndCirc

        availableNow()
        availablityDate()
        availableThru()
        restrictions()
        itemId()
        renewable()
        onHold()
        enumAndChron()
        midspine()
        temporaryLocation()

Net::Z3950::APDU::DiagRecs

No methods - just treat as a reference to an array of object references. The objects will typically be of class Net::Z3950::APDU::DefaultDiagFormat, but careful callers will check this, since any kind of EXTERNAL may be provided instead.

Net::Z3950::APDU::DefaultDiagFormat;

        diagnosticSetId()
        condition()
        addinfo()

Net::Z3950::APDU::OID

No longer exists. Previously this class had no methods - calling code just treated it as a reference to an array of integers. However, since the only thing anyone (including Net::Z3950::Record::GRS1::render()) ever did with it was smush it up into a string with

        join('.', @$oidRef)

we now just return the dot-separated OID string not blessed into any class (because scalars can't be blessed - only references to scalars, and we don't want the extra useless level of indirection).

Net::Z3950::APDU::ListEntries

No methods - just treat as a reference to an array of Net::Z3950::APDU::Entry

Net::Z3950::APDU::Entry

        termInfo()
        surrogateDiagnostic()

Usually, termInfo() returns a scanned term. When it returns an undefined value, consult <surrogateDiagnostic()> to find out why.

Net::Z3950::APDU::TermInfo

        term()
        globalOccurrences()

### Lots more to come here, including displayTerm

Net::Z3950::APDU::Term

        general()
        numeric()
        characterString()
        oid()
        dateTime()
        external()
        integerAndUnit()
        null()

At present only ``general'' terms are supported. The value of such a term may be obtained by calling <general()>. Terms of other types can not be obtained.

Net::Z3950::APDU::OtherInformation

No methods - just treat as a reference to an array of Net::Z3950::APDU::OtherInformationUnit

Net::Z3950::APDU::OtherInformationUnit

    which()
    characterInfo()
    binaryInfo()
    externallyDefinedInfo
    oid()

At present only ``externallyDefinedInfo'' units are supported.

Net::Z3950::APDU::SearchInfoReport

No methods - just treat as a reference to an array of Net::Z3950::APDU::SearchInfoReport_s

Net::Z3950::APDU::SearchInfoReport_s

    fullQuery()
    subqueryExpression()
    subqueryCount()

Net::Z3950::APDU::QueryExpression

    which()
    term()
    query()

At present only ``term'' query expressions are supported.

Net::Z3950::APDU::QueryExpressionTerm

    queryTerm()


AUTHOR

Mike Taylor <mike@indexdata.com>

First version Saturday 27th May 2000.