Adds support for multiple column (backwards compatible)

[Bharat311]

This PR allows defining multiple orderable columns ( fixes #23 ) like:

class Book
  include Mongoid::Document
  include Mongoid::Orderable

  orderable
  orderable column: serial, default: true
end

The code sets up a class_attribute orderable_configurations which is a hash of all the configurations and then generates helpers like:

@book.move_serial_to :top 
@book.next_serial_items

This code change is backwards compatible, so existing implementations will also work.

@book.move_to! 3
@book.next_item

In these case, the default configuration (default: true) or the first configuration is used.

Tested it for Mongoid 2, 3, 4 on a Rails 3 app - https://github.com/bharat311/mongoid_orderable_demo

[pyromaniac]

Such an awesome work! Could you please just fix 1.8.7 support and I'll merge it. I just don't want to reject 1.8.7 support because it costs almost nothing to bring it to gem.

Just replace all the new-style hashes with the old ones (https://travis-ci.org/pyromaniac/mongoid_orderable/jobs/27887206) please. Thanks in advance.

[Bharat311]

Hi @pyromaniac, thanks for the appreciation :)

Ruby 1.8.7 does not provide support for default arguments in #define_method, so i'll need to convert it to #class_eval for such methods.

Also, in ruby 1.8, to make an argument have a default value, the next argument(s) must also have a default value. so basically method such as:

def move_to!(column = :default, pos)
end

will also need to be changed.

I am agnostic to above changes, but not sure whether should we continue with the ruby 1.8 support ?

[pyromaniac]

We can drop it if it will be impossible to implement. So do something with it ;)

[Bharat311]

Cool... I'll work on it over the next couple of days and see how it goes.

[pyromaniac]

Wonderful, thanks!

[johnnyshields]

@pyromaniac let's drop Ruby 1.8 support. Ruby 1.8.x is 1 year past end-of-life, and it is not supported by Mongoid 3. I do not know of many other gems still supporting it.

[pyromaniac]

Let's do it!

[Bharat311]

@pyromaniac - i have fixed the build for ruby 1.8 also, it should be good to merge now.

[pyromaniac]

So awesome, thanks!

[Bharat311]

Thanks for the merge @pyromaniac

I think it would also be good to bump and release a new version of mongoid_orderable with the above changes, so i can use the released version directly.

[pyromaniac]

One more PR to merge

[j-miyake]

@Bharat311 - Hi, thank you for an awesome PR.
I would like to ask you how I workaround against a problem with this change.
I pulled the revision including those commits, then I got an error when I used inheritance. I have an abstract model and some inherited models for STI. I defined orderable configuration at the abstract model, for example:

class Foo
  include Mongoid::Document
  include Mongoid::Orderable
  orderable column: :position
end

class Bar < Foo
end

Before I pulled the latest revision, Bar class works with the orderable configuration I defined in Foo class.
However, after pulled, I got an error: NoMethodError: undefined method detect' for nil:NilClasswhen updating the position of aBardocument withmove_to!or specifying position number. The stacktrace when I usedmove_to!to modify the position of an instance ofBar` is here.

[1] pry> e.backtrace
=> ["/usr/local/rvm/gems/ruby-2.0.0-p451/bundler/gems/mongoid_orderable-8616c226798a/lib/mongoid/orderable/helpers.rb:10:in `default_orderable_column'",
 "/usr/local/rvm/gems/ruby-2.0.0-p451/bundler/gems/mongoid_orderable-8616c226798a/lib/mongoid/orderable/movable.rb:52:in `move_column_to'",
 "/usr/local/rvm/gems/ruby-2.0.0-p451/bundler/gems/mongoid_orderable-8616c226798a/lib/mongoid/orderable/movable.rb:6:in `move_to!'",
 . . .

I examined if the Bar class inherits the orderable configuration, then I found that it doesn’t. When I defined orderable in Bar directly, it works fine.

$ rails c
Loading development environment (Rails 4.0.0)
[1] pry(main)> class Foo
[1] pry(main)*   include Mongoid::Document  
[1] pry(main)*   include Mongoid::Orderable  
[1] pry(main)*   orderable column: :position  
[1] pry(main)* end  
=> [Foo]
[2] pry(main)> class Bar < Foo
[2] pry(main)* end  
=> nil
[3] pry(main)> Foo.orderable_configurations
=> {:position=>
  {:column=>:position,
   :index=>true,
   :scope=>nil,
   :base=>1,
   :field_opts=>{:type=>Integer}}}
[4] pry(main)> Bar.orderable_configurations
=> nil
[5] pry(main)> Bar.create position: 1
=> #<Bar _id: 53a91e497562751a31030000, position: 1, _type: "Bar">
[6] pry(main)> Bar.create position: 2
=> #<Bar _id: 53a91e4a7562751a31040000, position: 2, _type: "Bar">
[7] pry(main)> Bar.create position: 3
=> #<Bar _id: 53a91e4b7562751a31050000, position: 3, _type: "Bar">
[8] pry(main)> Bar.last.move_to! 2
NoMethodError: undefined method `detect' for nil:NilClass
from /usr/local/rvm/gems/ruby-2.0.0-p451/bundler/gems/mongoid_orderable-8616c226798a/lib/mongoid/orderable/helpers.rb:10:in `default_orderable_column'
[11] pry(main)> class Bar
[11] pry(main)*   orderable column: :position
[11] pry(main)* end  
=> [Bar]
[12] pry(main)> Bar.create position: 4
=> #<Bar _id: 53a91ec17562751a31060000, position: 4, _type: "Bar">
[13] pry(main)> Bar.create position: 5
=> #<Bar _id: 53a91ec27562751a31070000, position: 5, _type: "Bar">
[14] pry(main)> Bar.create position: 6
=> #<Bar _id: 53a91ec47562751a31080000, position: 6, _type: "Bar">
[15] pry(main)> Bar.last.move_to! 5
=> true
[16] pry(main)> Bar.find_by position: 5
=> #<Bar _id: 53a91ec47562751a31080000, position: 5, _type: "Bar">
[17] pry(main)> 

Are there any way to define the configuration in the abstract class and inherit it without defining again in the inherited classes?

Thanks!

[pyromaniac]

I thinks it might be fixed by using class_attribute :orderable_configurations.

[j-miyake]

@pyromaniac - Thanks! I sent a PR. https://github.com/pyromaniac/mongoid_orderable/pull/28