CriteriaOperator

This gem provides classes to create arbitrary complex conditions, by building an expression tree. Currently only basic operations are implemented.

Add this line to your application's Gemfile:

gem 'criteria_operator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install criteria_operator

For complete usage information, read the docs!

All relevant classes inherit from BaseOperator. Generally, you'll want to have a root node of this type, which will in turn contain the whole expression tree. Currently, there are the following operators:

The BinaryOperator is the most commonly used. It represents a binary operation, meaning an operator with a left and right hand side operand, each. The operands can be any BaseOperator. The operator has to be one of the following types:

• Equal (default)
• Not Equal
• Greater
• Greater or Equal
• Less
• Less or Equal

These types are represented by constants in the module BinaryOperatorType.

Usage example:

 # checks if the operands op1 and op2 are different
 operator = CriteriaOperator::BinaryOperator.new op1, op2, CriteriaOperator::BinaryOperatorType::NOT_EQUAL

The GroupOperator is used to connect an amount of conditions (BaseOperators) with either AND (default) or OR (see GroupOperatorType).

Usage example:

# checks if any of the conditions represented by operands op1 through op3 is true
operator = CriteriaOperator::GroupOperator.new [op1, op2, op3], CriteriaOperator::GroupOperatorType::OR

The UnaryOperator is used to perform simple checks or transform a value represented by an operand (BaseOperator). It takes on operand as well and has one of the following types:

• NOT (default)
• IS NULL
• Plus
• Minus

These types can be found in the UnaryOperatorType module.

Usage example:

# invert the sign of the result returned by operand op1
operator = CriteriaOperator::UnaryOperator.new op1, CriteriaOperator::UnaryOperatorType::MINUS

The OperandProperty is, as the name implies, an operand. This means, it does not work with any other operands like operators do. If presented as a tree, operands always are leaves. The OperandProperty describes a property through it's name.

Usage example:

# represents a column named 'integer_value' (without quotes)
operand = CriteriaOperator::OperandProperty.new 'integer_value'

The OperandValue is, just like the OperandProperty, an operand. It represents any kind of value.

Usage example:

# represents the numeric value forty-two
operand = CriteriaOperator::OperandValue.new 42

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/TheFlow0360/criteria_operator. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

Prerequisite to the acceptance of any pull requests is a successful build (this will be checked automatically) as well as test coverage and complete documentation.

The gem is available as open source under the terms of the MIT License.