|
|
| |
WebService::ISBNDB::API::Categories(3) |
User Contributed Perl Documentation |
WebService::ISBNDB::API::Categories(3) |
WebService::ISBNDB::API::Categories - Data class for category information
use WebService::ISBNDB::API::Categories;
$ray_authors = WebService::ISBNDB::API::Categories->
search({ name => 'alphabetically.authors.r.a.y' });
The WebService::ISBNDB::API::Categories class extends the
WebService::ISBNDB::API class to add attributes specific to the data
isbndb.com provides on categories.
The following methods are specific to this class, or overridden from the
super-class.
The constructor for this class may take a single scalar argument in lieu of a
hash reference:
- new($CATEGORY_ID|$ARGS)
- This constructs a new object and returns a referent to it. If the
parameter passed is a hash reference, it is handled as normal, per
Class::Std mechanics. If the value is a scalar, it is assumed to be
the category's ID within the system, and is looked up by that.
If the argument is the hash-reference form, then a new object
is always constructed; to perform searches see the search() and
find() methods. Thus, the following two lines are in fact
different:
$book = WebService::ISBNDB::API::Categories->
new({ id => "arts.music" });
$book = WebService::ISBNDB::API::Categories->new('arts.music');
The first creates a new object that has only the
"id" attribute set. The second returns
a new object that represents the category named
"arts.music", with all data
present.
The class also defines:
- copy($TARGET)
- Copies the target object into the calling object. All attributes
(including the ID) are copied. This method is marked
"CUMULATIVE" (see Class::Std), and any sub-class of this class
should provide their own copy() and also mark it
"CUMULATIVE", to ensure that all attributes at all levels are
copied.
See the copy() method in WebService::ISBNDB::API.
The following attributes are used to maintain the content of a category object:
- id
- The unique ID within the isbndb.com system for this category.
- name
- The name of the category.
- parent
- The parent category, if there is one, that this category falls under.
- summary
- A brief summary of the category, if available.
- depth
- The depth of the category in the hierarchy. Top-level categories are at a
depth of 0. "arts.opera.regions.france",
for example, is at a depth of 3.
- element_count
- Not documented in the isbndb.com API; appears be the number of
books in the category and all of its sub-categories.
- sub_categories
- A list of category objects for the sub-categories that fall below this
one.
The following accessors are provided to manage these
attributes:
- get_id
- Return the category ID.
- set_id($ID)
- Sets the category ID. This method is restricted to this class, and cannot
be called outside of it. In general, you shouldn't need to set the ID
after the object is created, since isbndb.com is a read-only
source.
- get_name
- Return the category's name.
- set_name($NAME)
- Set the name to the value in $NAME.
- get_parent
- Return the WebService::ISBNDB::API::Categories object that
represents this category's parent. If this is a top-level category, then
the method returns "undef".
- set_parent($PARENT)
- Set the category's parent to the value in $PARENT.
This may be an object, or it may be a category ID. If the value is not an
object, the next call to get_parent() will attempt to convert it to
one by calling the service.
- get_summary
- Get the category summary.
- set_summary($SUMMARY)
- Set the category summary to $SUMMARY.
- get_depth
- Get the category depth.
- set_depth($DEPTH)
- Set the category depth to $DEPTH.
- get_element_count
- Get the count of elements.
- set_element_count($COUNT)
- Set the element count.
- get_sub_categories
- Return a list-reference of the sub-categories for the category. Each
element of the list will be an instance of
WebService::ISBNDB::API::Categories.
- set_sub_categories($CATEGORIES)
- Set the sub-categories to the list-reference given in
$CATEGORIES. When the category object is first
created from the XML data, this list is populated with the IDs of the
sub-categories. They are not converted to objects until requested (via
get_sub_categories()) by the user.
Besides the constructor and the accessors, the following methods are provided
for utility:
- find($ARG|$ARGS)
- This is a specialization of find() from the parent class. It allows
the argument passed in to be a scalar in place of the usual hash
reference. If the value is a scalar, it is searched as though it were the
ID. If the value is a hash reference, it is passed to the super-class
method.
- normalize_args($ARGS)
- This method maps the user-visible arguments as defined for find()
and search() into the actual arguments that must be passed to the
service itself. In addition, some arguments are added to the request to
make the service return extra data used for retrieving categories,
location, etc. The method changes $ARGS in place,
and also returns $ARGS as the value from the
method.
See the next section for an explanation of the available keys for
searches.
Both find() and search() allow the user to look up data in the
isbndb.com database. The allowable search fields are limited to a
certain set, however. When either of find() or search() are
called, the argument to the method should be a hash reference of key/value
pairs to be passed as arguments for the search (the exception being that
find() can accept a single string, which has special meaning as
detailed earlier).
Searches in the text fields are done in a case-insensitive
manner.
The available search keys are:
- name
- The value should be a text string. The search returns categories whose
name matches the string.
- id|category_id
- The value should be a text string. The search returns the category whose
ID in the system matches the value.
- parent|parent_id
- You can also search by the parent. The search-key
"parent" will accept either a string
(taken as the ID) or a Categories object, in which case the ID is derived
from it. If the key used is "parent_id",
the value is assumed to be the ID.
Note that the names above may not be the same as the corresponding
parameters to the service. The names are chosen to match the related
attributes as closely as possible, for ease of understanding.
Get the record for the ID "science":
$science = WebService::ISBNDB::API::Categories->find('science');
Find all category records that are sub-categories of
"science":
$science2 = WebService::ISBNDB::API::Categories->
search({ parent => $science });
The data returned by this class is only as accurate as the data retrieved from
isbndb.com.
The list of results from calling search() is currently
limited to 10 items. This limit will be removed in an upcoming release, when
iterators are implemented.
Randy J. Ray <rjray@blackperl.com>
This module and the code within are released under the terms of the Artistic
License 2.0 (http://www.opensource.org/licenses/artistic-license-2.0.php).
This code may be redistributed under either the Artistic License or the GNU
Lesser General Public License (LGPL) version 2.1
(http://www.opensource.org/licenses/lgpl-license.php).
Visit the GSP FreeBSD Man Page Interface. Output converted with ManDoc. |