module Aquarium::Utils::OptionsUtils

OptionsUtils¶ ↑

Support parsing and processing of key-value pairs of options, where the values are always converted to Sets. Types including this module should have their initialize methods call this module's init_specification to do the options processing. See its documentation for more details.

Several class methods are included for defining convenience instance methods. For example, for options :foo and :bar, calling:

canonical_options_given_methods :foo, :bar

will define several methods for each option specified, e.g.,:

foo_given    # => returns the value of @specification[:foo]
foo_given?   # => returns true "foo_given" is not nil or empty.
bar_given    # etc...
bar_given?

If you would like corresponding reader and writer methods, pass a list of the keys for which you want these methods defined to one of the following methods:

canonical_option_reader   :foo, :bar   # analogous to attr_reader
canonical_option_writer   :foo, :bar   # analogous to attr_writer
canonical_option_accessor :foo, :bar   # analogous to attr_accessor

For all of these methods, you can also pass CANONICAL_OPTIONS (discussed below) to define methods for all of the “canonical” options, e.g.,

canonical_option_accessor CANONICAL_OPTIONS

These methods are not defined by default to prevent accidentally overriding other methods that you might have defined with the same names. Also, note that the writer methods will convert the inputs to sets, following the conventions for the options and the readers will return the sets. If you want different handling, you'll have to provide custom implementations.

Note that special-case accessor methods are already defined for the :noop and :logger options (discussed below) where the writers expect single values, not sets, and the readers return the single values. (Yea, it's a bit inconsistent…)

Finally, these canonical_option_* methods should only be called with the keys for the CANONICAL_OPTIONS. The keys are considered the “canonical options”, while the values for the keys are synonyms that can be used instead.

This module also defines several universal options that will be available to all types that include this module:

:logger

A Ruby standard library Logger used for any messages. A default system-wide logger is used otherwise. The corresponding logger and logger= accessors are defined.

:logger_stream

An an alternative to defining the logger, you can define just the output stream where log output will be written. If this option is specified, a new logger will be created for the instance with this output stream. There are no corresponding accessors; use the appropriate methods on the logger object instead.

:severity

The logging severity level, one of the Logger::Severity values or a corresponding integer value. If this option is specified, a new logger will be created for the instance with this output stream. There are no corresponding accessors; use the corresponding methods on the logger object instead.

:noop => options_hash[:noop] || false

If true, don't do “anything”, the interpretation of which will vary with the type receiving the option. For example, a type might go through some initialization, such as parsng its options, but do nothing after that. Primarily useful for debugging and testing.

The value can be accessed through the noop and noop= accessors.