NAME
SYNOPSIS
ABSTRACT
DESCRIPTION
METHODS
SEE ALSO
BUGS
AUTHORS
COPYRIGHT

NAME

Persistent::DataType::String - A Character String Class

SYNOPSIS

  use Persistent::DataType::String;
  use English;

  eval {  ### in case an exception is thrown ###

    ### allocate a string ###
    my $string = new Persistent::DataType::String($value,
                                                  $max_length);

    ### get/set value of string ###
    $value = $string->value($new_value);

    ### get length of string ###
    my $length = $string->length();

    ### get/set maximum length of string ###
    my $max = $string->max_length($new_max);

    ### returns 'eq' for strings ###
    my $cmp_op = $string->get_compare_op();
  };

  if ($EVAL_ERROR) {  ### catch those exceptions! ###
    print "An error occurred: $EVAL_ERROR\n";
  }

ABSTRACT

This is a character string class used by the Persistent framework of classes to implement the attributes of objects. This class provides methods for accessing the value, length, maximum length, and comparison operator of a character string.

This class is usually not invoked directly, at least not when used with the Persistent framework of classes. However, the constructor arguments of this class are usually of interest when defining the attributes of a Persistent object since the add_attribute method of the Persistent classes instantiates this class directly. Also, the arguments to the value method are of interest when dealing with the accessor methods of the Persistent classes since the accessor methods pass their arguments to the value method and return the string value from the value method.

This class is part of the Persistent base package which is available from:

  http://www.bigsnow.org/persistent
  ftp://ftp.bigsnow.org/pub/persistent

DESCRIPTION

Before we get started describing the methods in detail, it should be noted that all error handling in this class is done with exceptions. So you should wrap an eval block around all of your code. Please see the Persistent documentation for more information on exception handling in Perl.

METHODS

Constructor -- Creates the String Object

  eval {
    my $string = new Persistent::DataType::String($value,
                                                  $max_length);
  };
  croak "Exception caught: $@" if $@;

Initializes a character string object. This method throws Perl execeptions so use it with an eval block.

Parameters:

$value: Actual value of the string. This argument is optional and may be set to undef.
$max_length: Maximum length of the string value. This argument is optional and will be initialized to an unlimitied length (0) as a default.

value -- Accesses the Value of the String

  eval {
    ### set the value ###
    $string->value($value);

    ### get the value ###
    $value = $string->value();
  };
  croak "Exception caught: $@" if $@;

Sets the value of the string and/or returns the value. This method throws Perl execeptions so use it with an eval block.

Parameters:

$value: Actual value of the string. This argument is optional and may be set to undef.

get_compare_op -- Returns the Comparison Operator

  $cmp_op = $string->get_compare_op();

Returns the comparison operator for the String class which is 'cmp'. This method does not throw execeptions.

Parameters:

None

length -- Returns the Length of the String

  eval {
    $value = $string->length();
  };
  croak "Exception caught: $@" if $@;

Returns the length of the string. This method throws Perl execeptions so use it with an eval block.

Parameters:

None

max_length -- Accesses the Maximum Length of the String

  eval {
    ### set the maximum length ###
    $string->max_length($new_max);

    ### get the maximum length ###
    $max_length = $string->max_length();
  };
  croak "Exception caught: $@" if $@;

Sets the maximum length of the string and/or returns it. This method throws Perl execeptions so use it with an eval block.

Parameters:

$max_length: Maximum length of the string value. If the maximum length is set to undef, the empty string (''), or 0, then the string has an unlimited maximum length.

BUGS

This software is definitely a work in progress. So if you find any bugs please email them to me with a subject of 'Persistent Bug' at:

  winters@bigsnow.org

And you know, include the regular stuff, OS, Perl version, snippet of code, etc.

AUTHORS

  David Winters <winters@bigsnow.org>