E. Choroba > Treex-PML-2.17 > Treex::PML::Factory

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NAME ^

Treex::PML::Factory - a base class for Treex::PML object factories

SYNOPSIS ^

   use Treex::PML;
   use MyTreex::PML::Factory;

   MyTreex::PML::Factory->make_default();

   # These class methods invoke similarly named methods on the default
   # factory; the default factory method's are responsible for
   # creating and returning the corresponding objects.

   Treex::PML::Factory->createPMLSchema(...)
   Treex::PML::Factory->createPMLInstance(...)

   Treex::PML::Factory->createDocument(..)
   Treex::PML::Factory->createDocumentFromFile(..)

   Treex::PML::Factory->createFSFormat(..)

   Treex::PML::Factory->createNode(..)
   Treex::PML::Factory->createTypedNode($decl,...);

   Treex::PML::Factory->createList(...)
   Treex::PML::Factory->createSeq(...)
   Treex::PML::Factory->createAlt(...)
   Treex::PML::Factory->createContainer(...)
   Treex::PML::Factory->createStructure(...)

DESCRIPTION ^

This class maintains a default factory for creating Treex::PML objects and delegates create...() methods called as class methods to the default factory.

Note that this class does not implement a factory, Treex::PML::StandardFactory does that.

This class provides means for creating various types of Treex::PML-like objects without having to name particular classes. The user can plug in their own default factory in order to replace the default Treex::PML class hierarchy with their own one. The classes in the user hierarchy typically derive from the corresponding classes in the Treex::PML hierarchy; if not, they must at least implement the same interfaces and use the same types of references for the underlying objects (or overloading to them, so that also low-level code using HASH or ARRAY dereferencing on objects still works).

User can define factory by implementing all the create* methods as object methods. The factory must be derived from the 'Treex::PML::Factory' class or, alternatively, provide a constructor 'new' and implement the DOES method which then returns true if 'Treex::PML::Factory' is passed to it as an argument.

CLASS METHODS

$class->make_default()

If inherited by a customized factory class, makes the invocant class the default factory. Every factory class should either inherit this method or reimplement it using a call to Treex::PML::Factory-set_default_factory>.

$class->new(name=>value, ...)

If inherited by a customized factory class, creates a new instance of that class. The default constructor will create a blessed hash reference using the constructor arguments to populate the hash with name=>value pairs.

Treex::PML::Factory->get_default_factory()

Returns the default factory (usually a singleton Treex::PML::Factory object).

Treex::PML::Factory->set_default_factory($default_factory)

Change the default factory to a given object (the object must implment the Treex::PML::Factory interface).

METHODS FOR CREATING OBJECTS

The following functions must be implemented by custom factory classes as object methods, but should be called as class methods of the 'Treex::PML::Factory' class. The class methods of 'Treex::PML::Factory' delegate the call to the default factory.

Treex::PML::Factory->createPMLSchema({ option => value, ... })

Parses an XML representation of a PML Schema from a string, filehandle, local file, or URL, processing the modular instructions as described in

  L<http://ufal.mff.cuni.cz/jazz/PML/doc/pml_doc.html#processing>

and returns the corresponding object implementing the interface or Treex::PML::Schema. One of the following options must be given:

string

a XML string to parse

filename

a file name or URL

fh

a file-handle (IO::File, IO::Pipe, etc.) open for reading

The following options are optional:

base_url

base URL for referred schemas (usefull when parsing from a file-handle or a string)

use_resources

if this option is used with a true value, the parser will attempt to locate referred schemas also in Treex::PML resource paths.

revision, minimal_revision, maximal_revision

put constraints on the revision number of the schema.

validate

if this option is used with a true value, the parser will validate the schema on the fly using a RelaxNG grammar given using the relaxng_schema parameter; if relaxng_schema is not given, the file 'pml_schema_inline.rng' searched for in Treex::PML resource paths is assumed.

relaxng_schema

a particular RelaxNG grammar to validate against. The value may be an URL or filename for the grammar in the RelaxNG XML format, or a XML::LibXML::RelaxNG object representation. The compact format is not supported.

Treex::PML::Factory->createPMLInstance({ option=>value, ...})

Without arguments (the option HashRef) creates a empty object implementing the Treex::PML::Instance interface.

If called with the option HashRef, a new object implementing the Treex::PML::Instance interface is created and its content is read from a given XML input in the PML format. The input can be a file, filehandle, string, or a DOM tree. The arguments are described in the documentation of the the load() method of Treex::PML::Instance.

Treex::PML::Factory->createDocument({ option => value, ... })

Creates a new empty object implementing the Treex::PML::Document interface. The options are used to initialize the object's attributes and include: name, format, trees, backend, FS, hint, patterns, tail, save_status. See the documentation of the create() method of Treex::PML::Document for details.

Treex::PML::Factory->createDocumentFromFile($filename, { option => value, ... })

Creates a new object implementing the Treex::PML::Document interface and reads its content from a given file. The arguments are described in the documentation of the the load() method of Treex::PML::Document.

Treex::PML::Factory->createFSFormat($definition)

Return a new object implementing the Treex::PML::FSFormat interface. The argument can be a HashRef containing the FS format definition in parsed from, or an ARRAY reference (whose elements are individual lines of the FS format definition) or a GLOB reference with an input stream from which the FS format definition is to be read.

Treex::PML::Factory->createNode($hashRef?,$reuse?)

Return a new node object implementing the Treex::PML::Node interface, using given HashRef reference as the source of initial set of attributes; if the $reuse argument is true, the HashRef may be actually blessed into the new class (if supported by the implementation).

Treex::PML::Factory->createTypedNode($pml_type_decl,...);

or

Treex::PML::Factory->createTypedNode($type_name,$pml_schema,...);

Return a new node object implementing the Treex::PML::Node interface, associated with the given PML type (passed either as a Treex::PML::Schema::Decl object or as the type name followed by a PML schema object).

Treex::PML::Factory->createList($arrayRef?,$reuse?)

Return a new list (object implementing the Treex::PML::List interface), populated with the values passed in the (optional) ArrayRef. If the $reuse argument is true, the given ArrayRef may actually be reblessed into the target class (if supported by the implementation).

Treex::PML::Factory->createAlt($arrayRef?,$reuse?)

Return a new alternative (object implementing the Treex::PML::Alt interface), populated with the values passed in the (optional) ArrayRef. If the $reuse argument is true, the given ArrayRef may actually be reblessed into the target class (if supported by the implementation).

Treex::PML::Factory->createSeq($arrayRef?, $content_pattern?,$reuse?)

Return a new sequence (object implementing the Treex::PML::Seq interface). The object gets populated by elements from a given ArrayRef (if given). Each element of the ArrayRef should be a Treex::PML::Seq::Element object. The second optional argument is a regular expression constraint which can be stored in the object and used later for validating its content (see validate() method of Treex::PML::Seq). If the $reuse argument is true, the ArrayRef can be used directly as the container for the content of the sequence (if supported by the implementation); otherwise it is copied.

Treex::PML::Factory->createContainer($value?, $hashRef?, $reuse?)

Create a new container (object implementing the Treex::PML::Container interface). The the initial value for the container's value with $value and its attributes with the name-value pairs from the given HashRef. If $reuse is true, the HashRef passed may actually be reblessed into the target class (if supported by the implementation).

Treex::PML::Factory->createStructure($hashRef?, $reuse?)

Create a new structure (object implementing the Treex::PML::Struct interface). The structure is initialized with the name-value pairs from the given HashRef (optional). If $reuse is true, the HashRef may actually be reblessed into the target class (if supported by the implementation).

DOES($interface)

Check whether the class implements a given interface (role). Note, the class Treex::PML::Factory itself does not implement the Treex::PML::Factory interface, but assumes that anything derived from it does!

EXPORT

None by default.

SEE ALSO ^

Treex::PML

COPYRIGHT AND LICENSE ^

Copyright (C) 2010 by Petr Pajas

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.2 or, at your option, any later version of Perl 5 you may have available.

BUGS ^

None reported... yet.

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