SYNOPSIS

use Bio::MAGE::Description;

DESCRIPTION

This is a package module that encapsulates a number of classes in the Bio::MAGE hierarchy. These classes belong to the Description package of the MAGE-OM object model.

CLASSES

The Bio::MAGE::Description module contains the following Bio::MAGE classes:

• Description
• DatabaseEntry
• Database
• ExternalReference
• OntologyEntry

CLASS METHODS

@class_list = Bio::MAGE::Description::classes();

This method returns a list of non-fully qualified class names (i.e. they do not have 'Bio::MAGE::' as a prefix) in this package.

$obj = class->new(%parameters)

The "new()" method is the class constructor.

Parameters: if given a list of name/value parameters the corresponding slots, attributes, or associations will have their initial values set by the constructor.

Return value: It returns a reference to an object of the class.

Side effects: It invokes the "initialize()" method if it is defined by the class.

@names = class->get_slot_names()

The "get_slot_names()" method is used to retrieve the name of all slots defined in a given class.

NOTE: the list of names does not include attribute or association names.

Return value: A list of the names of all slots defined for this class.

Side effects: none

@name_list = get_attribute_names()

returns the list of attribute data members for this class.

@name_list = get_association_names()

returns the list of association data members for this class.

@class_list = get_superclasses()

returns the list of superclasses for this class.

@class_list = get_subclasses()

returns the list of subclasses for this class.

$name = class_name()

Returns the full class name for this class.

$package_name = package_name()

Returns the base package name (i.e. no 'namespace::') of the package that contains this class.

%assns = associations()

returns the association meta-information in a hash where the keys are the association names and the values are "Association" objects that provide the meta-information for the association.

INSTANCE METHODS

$obj_copy = $obj->new()

When invoked with an existing object reference and not a class name, the "new()" method acts as a copy constructor - with the new object's initial values set to be those of the existing object.

Parameters: No input parameters are used in the copy constructor, the initial values are taken directly from the object to be copied.

Return value: It returns a reference to an object of the class.

Side effects: It invokes the "initialize()" method if it is defined by the class.

$obj->set_slots(%parameters)

$obj->set_slots(\@name_list, \@value_list)

The "set_slots()" method is used to set a number of slots at the same time. It has two different invocation methods. The first takes a named parameter list, and the second takes two array references.

Return value: none

Side effects: will call "croak()" if a slot_name is used that the class does not define.

@obj_list = $obj->get_slots(@name_list)

The "get_slots()" method is used to get the values of a number of slots at the same time.

Return value: a list of instance objects

Side effects: none

$val = $obj->set_slot($name,$val)

The "set_slot()" method sets the slot $name to the value $val

Return value: the new value of the slot, i.e. $val

Side effects: none

$val = $obj->get_slot($name)

The "get_slot()" method is used to get the values of a number of slots at the same time.

Return value: a single slot value, or undef if the slot has not been initialized.

Side effects: none

$val = $description->xml_lists()

$inval = $description->xml_lists($inval)

This is the unified setter/getter method for the xml_lists slot.

If $inval is specified, the setter method is invoked, with no parameters, the getter method is invoked.

Input parameters: the optional $inval will invoke the setter method.

Return value: for both setter and getter the current value of the xml_lists slot

Side effects: none

Exceptions: none

$val = $description->tagname()

$inval = $description->tagname($inval)

This is the unified setter/getter method for the tagname slot.

If $inval is specified, the setter method is invoked, with no parameters, the getter method is invoked.

Input parameters: the optional $inval will invoke the setter method.

Return value: for both setter and getter the current value of the tagname slot

Side effects: none

Exceptions: none

$val = $description->database_list()

$inval = $description->database_list($inval)

This is the unified setter/getter method for the database_list slot.

If $inval is specified, the setter method is invoked, with no parameters, the getter method is invoked.

Input parameters: the optional $inval will invoke the setter method.

Return value: for both setter and getter the current value of the database_list slot

Side effects: none

Exceptions: none

$array_ref = $description->getDatabase_list()

This method handles the list for the "Bio::MAGE::Description::Database" class. It returns a reference to an array of the class objects that have been associated with the package instance.

This is useful when retrieving data from parsed MAGE-ML file.

$description->addDatabase(@vals)

This method is an interface for adding "Bio::MAGE::Description::Database" objects to the "database_list" list. It is generally used by generic methods such as those in the XMLWriter.

Input parameters: the list of values @vals to add to the owner association. NOTE: submitting a single value is permitted.

Return value: none

Side effects: none

Exceptions: will call "croak()" if no input parameters are specified , or if any of the objects in @vals is not a subclass of class "Bio::MAGE::Description::Database"

$description->obj2xml($writer)

Write out this object, and all sub-objects, as XML using the supplied $writer to actually do the XML formatting.

Input parameters: $writer must be an XML writer, e.g. an instance of Bio::MAGE::XML::Writer. It must have methods: write_start_tag(), write_end_tag(), and obj2xml().

Return value: none

Side effects: all writing is delegated to the $writer - it's write_start_tag() and write_end_tag() methods are invoked with the appropriate data, and all class sub-objects of the "Bio::MAGE::Description" instance will have their obj2xml() methods invoked in turn. By allowing the $writer to do the actual formatting of the output XML, it enables the user to precisely control the format.

Exceptions: will call "croak()" if no identifier has been set for the "Bio::MAGE::Description" instance.

$description->register($obj)

Store an object for later writing as XML.

Input parameters: object to be added to the list of registered objects.

Return value: none

Side effects: if $obj needs to be stored by this class, a reference will be stored in the correct XML list for this class.

Exceptions: none

SLOTS, ATTRIBUTES, AND ASSOCIATIONS

In the Perl implementation of MAGE-OM classes, there are three types of class data members: "slots", "attributes", and "associations".

SLOTS

This API uses the term "slot" to indicate a data member of the class that was not present in the UML model and is used for mainly internal purposes - use only if you understand the inner workings of the API. Most often slots are used by generic methods such as those in the XML writing and reading classes.

Slots are implemented using unified getter/setter methods:

$var = $obj->slot_name();

Retrieves the current value of the slot.

$new_var = $obj->slot_name($new_var);

Store $new_var in the slot - the return value is also $new_var.

@names = $obj->get_slot_names()

Returns the list of all slots in the class.

DATA CHECKING: No data type checking is made for these methods.

ATTRIBUTES AND ASSOCIATIONS

The terms "attribute" and "association" indicate data members of the class that were specified directly from the UML model.

In the Perl implementation of MAGE-OM classes, association and attribute accessors are implemented using three separate methods:

get*

Retrieves the current value.

NOTE: For associations, if the association has list cardinality, an array reference is returned.

DATA CHECKING: Ensure that no argument is provided.

set*

Sets the current value, replacing any existing value.

NOTE: For associations, if the association has list cardinality, the argument must be an array reference. Because of this, you probably should be using the add* methods.

DATA CHECKING: For attributes, ensure that a single value is provided as the argument. For associations, if the association has list cardinality, ensure that the argument is a reference to an array of instances of the correct MAGE-OM class, otherwise ensure that there is a single argument of the correct MAGE-OM class.

add*

NOTE: Only present in associations with list cardinality.

Appends a list of objects to any values that may already be stored in the association.

DATA CHECKING: Ensure that all arguments are of the correct MAGE-OM class.

GENERIC METHODS

The unified base class of all MAGE-OM classes, "Bio::MAGE::Base", provides a set of generic methods that will operate on slots, attributes, and associations:

$val = $obj->get_slot($name)

\@list_ref = $obj->get_slots(@name_list);

$val = $obj->set_slot($name,$val)

$obj->set_slots(%parameters)

$obj->set_slots(\@name_list, \@value_list)

See elsewhere in this page for a detailed description of these methods.

AUTHOR

Jason E. Stewart (jasons 'at' cpan 'dot' org)