Rose::Class::MakeMethods::Generic(3p)

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) 2006 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.