Mojo::Cache::Role::GetDefault - Default values in get

my $cache = Mojo::Cache->new->with_roles('+GetDefault');

# set 'abc' for $key in the cache if $key does not exist in the cache.
# 'abc' will also be the return value
my $value = $cache->get($key, 'abc');

# sub is called and passed $key if $key does not exist in the cache.
# Return value is set in cache for $key and returned by get.
# $key is also available as the first argument
my $value = $cache->get($key, sub { "default value for key $_" });

# use get normally without any default value like in Mojo::Cache
my $value = $cache->get($key);

# set a default for all gets.
# this default will be overridden by any default passed to get.
$cache = $cache->default('abc');
$cache = $cache->default(sub { ... });

Mojo::Cache::Role::GetDefault allows Mojo::Cache to set and return default in "get" when a key does not exist.

my $default = $cache->default;
$cache      = $cache->default('abc');

# or use a sub that is passed the key as $_ and as the first argument
$cache = $cache->default(sub { "default value for key $_" });
$cache = $cache->default(sub { "default value for key $_[0]" });

The default value that is set and returned by "get" if a key does not exist in the cache. "default" may be a static value or a subroutine that returns a value. The key is available to the subroutine as $_ and as the first argument.

You may clear "default" with "clear_default".

"default" will be overridden by any default passed to "get".

• get($key, [$default])

  set 'abc' for $key in the cache if $key does not exist in the cache.

  'abc' will also be the return value

  my $value = $cache->get($key, 'abc');

  sub is called and passed $key if $key does not exist in the cache.

  Return value is set in cache for $key and returned by get.

  $key is also available as the first argument

  my $value = $cache->get($key, sub { "default value for $_" });

  use get normally without any default value like in Mojo::Cache

  my $value = $cache->get($key);

"get" works like "get" in Mojo::Cache, but allows an optional default value to be set and returned if the key does not exist in the cache. $default may be a static value or a subroutine that returns a value. The key is available to the subroutine as $_ and as the first argument.

Any $default passed to "get" will override any default set in "default".

Providing no $default makes "get" behave exactly like "get" in Mojo::Cache.

$cache = $cache->clear_default;

Clears any existing default set by "default".

if ($cache->exists($key)) {
  ...
}

Returns true if a cached value exists for the provided key, false otherwise.

"exists" is composed from Mojo::Cache::Role::Exists. See that module for more information.

Adam Hopkins [email protected]

Copyright 2019- Adam Hopkins

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

• Mojo::Cache
• Mojo::Cache::Role::Exists
• Mojo::Base