NAME

Rose::Class::MakeMethods::Generic - Create simple class methods.

SYNOPSIS

  package MyClass;

  use Rose::Class::MakeMethods::Generic
  (
    scalar => 
    [
      'error',
      'type' => { interface => 'get_set_init' },
    ],

    inheritable_scalar => 'name',
  );

  sub init_type { 'special' }
  ...

  package MySubClass;
  our @ISA = qw(MyClass);
  ...

  MyClass->error(123);

  print MyClass->type; # 'special'

  MyClass->name('Fred');
  print MySubClass->name; # 'Fred'

  MyClass->name('Wilma');
  print MySubClass->name; # 'Wilma'

  MySubClass->name('Bam');
  print MyClass->name;    # 'Wilma'
  print MySubClass->name; # 'Bam'

DESCRIPTION

Rose::Class::MakeMethods::Generic is a method maker that inherits from Rose::Object::MakeMethods. See the Rose::Object::MakeMethods documentation to learn about the interface. The method types provided by this module are described below. All methods work only with classes, not objects.

METHODS TYPES

scalar

Create get/set methods for scalar class attributes.

Options

init_method

The name of the class method to call when initializing the value of an undefined attribute. This option is only applicable when using the get_set_init interface. Defaults to the method name with the prefix init_ added.

interface

Choose one of the two possible interfaces. Defaults to get_set.

Interfaces

get_set

Creates a simple get/set accessor method for a class attribute. When called with an argument, the value of the attribute is set. The current value of the attribute is returned.

get_set_init

Behaves like the get_set interface unless the value of the attribute is undefined. In that case, the class method specified by the init_method option is called and the attribute is set to the return value of that method.

Example:

    package MyClass;

    use Rose::Class::MakeMethods::Generic
    (
      scalar => 'power',
      'scalar --get_set_init' => 'name',
    );

    sub init_name { 'Fred' }
    ...

    MyClass->power(99);    # returns 99
    MyClass->name;         # returns "Fred"
    MyClass->name('Bill'); # returns "Bill"

inheritable_scalar

Create get/set methods for scalar class attributes that are inherited by subclasses until/unless their values are changed.

Options

interface

Choose the interface. This is kind of pointless since there is only one interface right now. Defaults to get_set, obviously.

Interfaces

get_set

Creates a get/set accessor method for a class attribute. When called with an argument, the value of the attribute is set and then returned.

If called with no arguments, and if the attribute was never set for this class, then a left-most, breadth-first search of the parent classes is initiated. The value returned is taken from first parent class encountered that has ever had this attribute set.

Example:

    package MyClass;

    use Rose::Class::MakeMethods::Generic
    (
      inheritable_scalar => 'name',
    );
    ...

    package MySubClass;
    our @ISA = qw(MyClass);
    ...

    package MySubSubClass;
    our @ISA = qw(MySubClass);
    ...

    $x = MyClass->name;       # undef
    $y = MySubClass->name;    # undef
    $z = MySubSubClass->name; # undef

    MyClass->name('Fred');
    $x = MyClass->name;       # 'Fred'
    $y = MySubClass->name;    # 'Fred'
    $z = MySubSubClass->name; # 'Fred'

    MyClass->name('Wilma');
    $x = MyClass->name;       # 'Wilma'
    $y = MySubClass->name;    # 'Wilma'
    $z = MySubSubClass->name; # 'Wilma'

    MySubClass->name('Bam');
    $x = MyClass->name;       # 'Wilma'
    $y = MySubClass->name;    # 'Bam'
    $z = MySubSubClass->name; # 'Bam'

    MyClass->name('Koop');
    MySubClass->name(undef);
    $x = MyClass->name;       # 'Koop'
    $y = MySubClass->name;    # undef
    $z = MySubSubClass->name; # undef

    MySubSubClass->name('Sam');
    $x = MyClass->name;       # 'Koop'
    $y = MySubClass->name;    # undef
    $z = MySubSubClass->name; # 'Sam'

hash

Create methods to manipulate a hash of class attributes.

Options

hash_key

The key to use for the storage of this attribute. Defaults to the name of the method.

interface

Choose which interface to use. Defaults to get_set.

Interfaces

get_set

If called with no arguments, returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to a hash, that hash reference is used as the new value for the attribute. Returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to an array, then a list of the hash values for each key in the array is returned.

If called with one argument, and it is not a reference to a hash or an array, then the hash value for that key is returned.

If called with an even number of arguments, they are taken as name/value pairs and are added to the hash. It then returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

Passing an odd number of arguments greater than 1 causes a fatal error.

get_set_all

If called with no arguments, returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to a hash, that hash reference is used as the new value for the attribute. Returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

Otherwise, the hash is emptied and the arguments are taken as name/value pairs that are then added to the hash. It then returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

clear

Sets the attribute to an empty hash.

reset

Sets the attribute to undef.

delete

Deletes the key(s) passed as arguments. Failure to pass any arguments causes a fatal error.

exists

Returns true of the argument exists in the hash, false otherwise. Failure to pass an argument or passing more than one argument causes a fatal error.

keys

Returns the keys of the hash in list context, or a reference to an array of the keys of the hash in scalar context. The keys are not sorted.

names

An alias for the keys interface.

values

Returns the values of the hash in list context, or a reference to an array of the values of the hash in scalar context. The values are not sorted.

Example:

    package MyClass;

    use Rose::Class::MakeMethods::Generic
    (
      hash =>
      [
        param        => { hash_key =>'params' },
        params       => { interface=>'get_set_all' },
        param_names  => { interface=>'keys',   hash_key=>'params' },
        param_values => { interface=>'values', hash_key=>'params' },
        param_exists => { interface=>'exists', hash_key=>'params' },
        delete_param => { interface=>'delete', hash_key=>'params' },

        clear_params => { interface=>'clear', hash_key=>'params' },
        reset_params => { interface=>'reset', hash_key=>'params' },
      ],
    );
    ...

    MyClass->params; # undef

    MyClass->params(a => 1, b => 2); # add pairs
    $val = MyClass->param('b'); # 2

    %params = MyClass->params; # copy hash keys and values
    $params = MyClass->params; # get hash ref

    MyClass->params({ c => 3, d => 4 }); # replace contents

    MyClass->param_exists('a'); # false

    $keys = join(',', sort MyClass->param_names);  # 'c,d'
    $vals = join(',', sort MyClass->param_values); # '3,4'

    MyClass->delete_param('c');
    MyClass->param(f => 7, g => 8);

    $vals = join(',', sort MyClass->param_values); # '4,7,8'

    MyClass->clear_params;
    $params = MyClass->params; # empty hash

    MyClass->reset_params;
    $params = MyClass->params; # undef

inheritable_hash

Create methods to manipulate a hash of class attributes that can be inherited by subclasses.

The hash of attributes is inherited by subclasses using a one-time copy. Any subclass that accesses or manipulates the hash in any way will immediately get its own private copy of the hash as it exists in the superclass at the time of the access or manipulation.

The superclass from which the hash is copied is the closest ("least super") class that has ever accessed or manipulated this hash. The copy is a "shallow" copy, duplicating only the keys and values. Reference values are not recursively copied.

Setting to hash to undef (using the 'reset' interface) will cause it to be re-copied from a superclass the next time it is accessed.

Options

hash_key

The key to use for the storage of this attribute. Defaults to the name of the method.

interface

Choose which interface to use. Defaults to get_set.

Interfaces

get_set

If called with no arguments, returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to a hash, that hash reference is used as the new value for the attribute. Returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to an array, then a list of the hash values for each key in the array is returned.

If called with one argument, and it is not a reference to a hash or an array, then the hash value for that key is returned.

If called with an even number of arguments, they are taken as name/value pairs and are added to the hash. It then returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

Passing an odd number of arguments greater than 1 causes a fatal error.

get_set_all

If called with no arguments, returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

If called with one argument, and that argument is a reference to a hash, that hash reference is used as the new value for the attribute. Returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

Otherwise, the hash is emptied and the arguments are taken as name/value pairs that are then added to the hash. It then returns a list of key/value pairs in list context or a reference to the actual hash used to store values in scalar context.

clear

Sets the attribute to an empty hash.

reset

Sets the attribute to undef.

delete

Deletes the key(s) passed as arguments. Failure to pass any arguments causes a fatal error.

exists

Returns true of the argument exists in the hash, false otherwise. Failure to pass an argument or passing more than one argument causes a fatal error.

keys

Returns the keys of the hash in list context, or a reference to an array of the keys of the hash in scalar context. The keys are not sorted.

names

An alias for the keys interface.

values

Returns the values of the hash in list context, or a reference to an array of the values of the hash in scalar context. The values are not sorted.

Example:

    package MyClass;

    use Rose::Class::MakeMethods::Generic
    (
      inheritable_hash =>
      [
        param        => { hash_key =>'params' },
        params       => { interface=>'get_set_all' },
        param_names  => { interface=>'keys',   hash_key=>'params' },
        param_values => { interface=>'values', hash_key=>'params' },
        param_exists => { interface=>'exists', hash_key=>'params' },
        delete_param => { interface=>'delete', hash_key=>'params' },

        clear_params => { interface=>'clear', hash_key=>'params' },
        reset_params => { interface=>'reset', hash_key=>'params' },
      ],
    );
    ...

    package MySubClass;
    our @ISA = qw(MyClass);
    ...

    MyClass->params; # undef

    MyClass->params(a => 1, b => 2); # add pairs
    $val = MyClass->param('b'); # 2

    %params = MyClass->params; # copy hash keys and values
    $params = MyClass->params; # get hash ref

    # Inherit a copy of params from MyClass
    $params = MySubClass->params; # { a => 1, b => 2 }

    MyClass->params({ c => 3, d => 4 }); # replace contents

    # MySubClass params are still as the existed at the time
    # they were originally copied from MyClass
    $params = MySubClass->params; # { a => 1, b => 2 }

    # MySubClass can manipulate its own params as it wishes
    MySubClass->param(z => 9);

    $params = MySubClass->params; # { a => 1, b => 2, z => 9 }

    MyClass->param_exists('a'); # false

    $keys = join(',', sort MyClass->param_names);  # 'c,d'
    $vals = join(',', sort MyClass->param_values); # '3,4'

    # Reset params (set to undef) so that they will be re-copied
    # from MyClass the next time they're accessed
    MySubClass->reset_params;

    MyClass->delete_param('c');
    MyClass->param(f => 7, g => 8);

    $vals = join(',', sort MyClass->param_values); # '4,7,8'

    # Inherit a copy of params from MyClass
    $params = MySubClass->params; # { d => 4, f => 7, g => 8 }

AUTHOR

John C. Siracusa (siracusa@mindspring.com)

COPYRIGHT

Copyright (c) 2005 by John C. Siracusa. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.