Template::Base
Author: Andy Wardley

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#### Template::* Modules

Next

#### Template::Config

Factory module for instantiating other TT2 modules

# Template::Base

## Base class module implementing common functionality

# Contents

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# SYNOPSIS

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    package My::Module;
    use base qw( Template::Base );

    sub _init {
        my ($self, $config) = @_;
        $self->{ doodah } = $config->{ doodah }
            || return $self->error("No 'doodah' specified");
        return $self;
    }

    package main;

    my $object = My::Module->new({ doodah => 'foobar' })
        || die My::Module->error();

# DESCRIPTION

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Base class module which implements a constructor and error reporting functionality for various Template Toolkit modules.

# PUBLIC METHODS

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## new(\%config)

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Constructor method which accepts a reference to a hash array or a list of `name => value` parameters which are folded into a hash. The `_init()` method is then called, passing the configuration hash and should return true/false to indicate success or failure. A new object reference is returned, or undef on error. Any error message raised can be examined via the error() class method or directly via the `$ERROR` package variable in the derived class.

    my $module = My::Module->new({ ... })
        || die My::Module->error(), "\n";

    my $module = My::Module->new({ ... })
        || die "constructor error: $My::Module::ERROR\n";

## error($msg, ...)

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May be called as an object method to get/set the internal `_ERROR` member or as a class method to get/set the `$ERROR` variable in the derived class's package.

    my $module = My::Module->new({ ... })
        || die My::Module->error(), "\n";

    $module->do_something()
        || die $module->error(), "\n";

When called with parameters (multiple params are concatenated), this method will set the relevant variable and return undef. This is most often used within object methods to report errors to the caller.

    package My::Module;

    sub foobar {
        my $self = shift;

        # some other code...

        return $self->error('some kind of error...')
            if $some_condition;
    }

## debug($msg, ...)

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Generates a debugging message by concatenating all arguments passed into a string and printing it to `STDERR`. A prefix is added to indicate the module of the caller.

    package My::Module;

    sub foobar {
        my $self = shift;

        $self->debug('called foobar()');

        # some other code...
    }

When the `foobar()` method is called, the following message is sent to `STDERR`:

    [My::Module] called foobar()

Objects can set an internal `DEBUG` value which the `debug()` method will examine. If this value sets the relevant bits to indicate `DEBUG_CALLER` then the file and line number of the caller will be appened to the message.

    use Template::Constants qw( :debug );

    my $module = My::Module->new({
        DEBUG => DEBUG_SERVICE | DEBUG_CONTEXT | DEBUG_CALLER,
    });

    $module->foobar();

This generates an error message such as:

    [My::Module] called foobar() at My/Module.pm line 6

# AUTHOR

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Andy Wardley <abw@wardley.org> http://wardley.org/

# COPYRIGHT

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Copyright (C) 1996-2007 Andy Wardley. All Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

# SEE ALSO

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Template

/modules/Template/Base.html last modified 10:57:44 31-May-2007