Module ActiveSupport::CachingTools::HashCaching
In: lib/active_support/caching_tools.rb

Provide shortcuts to simply the creation of nested default hashes. This pattern is useful, common practice, and unsightly when done manually.

Methods

Public Instance methods

Dynamically create a nested hash structure used to cache calls to method_name The cache method is named +#{method_name}_cache+ unless :as => :alternate_name is given.

The hash structure is created using nested Hash.new. For example:

  def slow_method(a, b) a ** b end

can be cached using hash_cache :slow_method, which will define the method slow_method_cache. We can then find the result of a ** b using:

  slow_method_cache[a][b]

The hash structure returned by slow_method_cache would look like this:

  Hash.new do |as, a|
    as[a] = Hash.new do |bs, b|
      bs[b] = slow_method(a, b)
    end
  end

The generated code is actually compressed onto a single line to maintain sensible backtrace signatures.

[Validate]