filter_matcher

filter your collection with ease

How to install?

gem install filter_matcher

What it does?

Invokes a method on filtered elements from a collection.

Example

Lets say we have following data about people:

db = [
  { :id => 1, :name => "John",  :age => 33, :homepage => "www.johny.com",     :matched => false },
  { :id => 2, :name => "Mike",  :age => 30, :homepage => "www.mikes.com",     :matched => false },
  { :id => 3, :name => "Johny", :age => 25, :homepage => "www.johny.com",     :matched => false },
  { :id => 4, :name => "Mike",  :age => 30, :homepage => "www.realmike.com",  :matched => false },
  { :id => 5, :name => "Dan",   :age => 25, :homepage => "www.danny.com",     :matched => false },
  { :id => 6, :name => "Dan",   :age => 40, :homepage => "www.fakedanny.com", :matched => false }
]

And we want to match them with the following input:

input = [
  { :name => "Mike", :age => 30, :homepage => "www.realmike.com" },
  { :name => "Dan", :homepage => "www.danny.com" }
]

We specifiy filters in order of importance and the method to be invoked on matched element(s):

input.each do |input|
  matcher(db, :single) do |m|
    m.filter do |col|
      col.select { |element| element[:name] == input[:name] }
    end

    m.filter do |col|
      col.select { |element| element[:age] == input[:age]}
    end

    m.filter do |col|
      col.select { |element| element[:homepage] == input[:homepage] }
    end

    m.match do |element|
      element[:matched] = true
    end
  end
end

The expected result is the db matched like:

db == [
  {:id => 1, :name => "John",  :age => 33, :homepage => "www.johny.com",     :matched => false}
  {:id => 2, :name => "Mike",  :age => 30, :homepage => "www.mikes.com",     :matched => false}
  {:id => 3, :name => "Johny", :age => 25, :homepage => "www.johny.com",     :matched => false}
  {:id => 4, :name => "Mike",  :age => 30, :homepage => "www.realmike.com",  :matched => true}
  {:id => 5, :name => "Dan",   :age => 25, :homepage => "www.danny.com",     :matched => true}
  {:id => 6, :name => "Dan",   :age => 40, :homepage => "www.fakedanny.com", :matched => false}
]

Visual examples

Filtering a collection with SingleMatcher

[1,2,3] --first_filter--> [2,3] ---second_filter--> [2] -> match

[1,2,3] --first_filter--> [] --> [1,2,3] --second_filter--> [3] -> match

[1,2,3] --first_filter--> [1,2] --second_filter--> [1,2] --third_filter--> [1] -> match

[1,2,3] --first_filter--> [] --> [1,2,3] --second_filter--> [] --> [1,2,3] --third_filter--> [] -> no match

[1,2,3] --first_filter--> [1,2,3] --second_filter--> [2,3] --third_filter--> [2,3] -> no match

Filtering a collection with FirstFromTopMatcher

[1,2,3] --first_filter--> [2,3] ---second_filter--> [2] -> matches 2

[1,2,3] --first_filter--> [] --> [1,2,3] --second_filter--> [3] -> matches 3

[1,2,3] --first_filter--> [1,2] --second_filter--> [1,2] --third_filter--> [1, 2] -> matches 1

[1,2,3] --first_filter--> [] --> [1,2,3] --second_filter--> [] --> [1,2,3] --third_filter--> [] -> no match

[1,2,3] --first_filter--> [1,2,3] --second_filter--> [2,3] --third_filter--> [2,3] -> matches 2

Filtering class example

Full PeopleMatcher class example, that is responsible only for the matching could look like that:

class PeopleMatcher
  include FilterMatcher

  attr_reader :db

  def initialize(db, input)
    @db, @input = db, input
  end

  def match
    @input.each do |input|
      collection = @db

     matcher(collection, :filter_type) do |m|
        m.filter do |col|
          # filtering code
        end

        m.filter do |col|
          # filtering code
        end

        m.match do |element|
          # match code
        end
      end
    end
  end
end

Usecases

Matching JSON, csv or hash data. Helpful to apply any filter that cannot be applied on DB level.

Contribution

Did you find it usefull anyhow? Please let me know, and if you want to improve it just send me an email or pull request.

Contributors:

Albert Llop, Sebastian Röbke

vysogot/filter_matcher