Mike Taylor > Net-Z3950-0.34 > Net::Z3950::APDU

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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()

Net::Z3950::APDU::PresentResponse

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

Net::Z3950::APDU::Close

        referenceId()
        closeReason()
        diagnosticInformation()

        as_text()       (render fields as printable string)

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::OPAC, Net::Z3950::APDU::MAB

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

Net::Z3950::APDU::GRS1

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

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::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).

AUTHOR ^

Mike Taylor <mike@tecc.co.uk>

First version Saturday 27th May 2000.

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