Module: Lims::Core::Persistence::Sequel::Filters

Included in:
Persistor
Defined in:
lib/lims-core/persistence/sequel/filters.rb

Overview

Implementes filter methods needed by persitors.

Constant Summary collapse

LIKE_OPERATOR = 
'LIKE'
COMPARISON_OPERATORS = 
["<", "<=", "=", ">=", ">", LIKE_OPERATOR]

Instance Method Summary collapse

Instance Method Details

#add_comparison_filter(dataset, comparison_criteria) ⇒ Persistor

Joins the comparison filter to the existing persistor.

Parameters:

  • dataset (Dataset)
  • criteria (Hash<String, Object>) —

    for the comparison

Returns:



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# File 'lib/lims-core/persistence/sequel/filters.rb', line 56

def add_comparison_filter(dataset, comparison_criteria)
  comparison_persistor = comparison_filter(comparison_criteria)
  self.class.new(self, dataset.join(comparison_persistor.dataset, :id => :key).qualify)
end

#comparison_filter(criteria) ⇒ Persistor

Implement a comparison filter for a Sequel::Persistor. Key being the name of the resource’s field and the value is a Hash. The key of the hash is a comparison operator and the value is the given value the filter do the comparison against.

Parameters:

  • criteria (Hash<String, Object>)

Returns:



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# File 'lib/lims-core/persistence/sequel/filters.rb', line 33

def comparison_filter(criteria)
  clause = ""
  criteria.each do |field, comparison_expression|
    comparison_expression.each do |operator, value|
      if operator.upcase == LIKE_OPERATOR
        operator = operator.upcase
        value = "%#{value}%" if operator == LIKE_OPERATOR
      end

      raise ArgumentError, "Not supported comparison operator has been given: '#{operator}'" unless COMPARISON_OPERATORS.include?(operator) 

      clause = clause + ') & (' unless clause == ""
      clause = clause + " #{field} " + operator + "'#{value}'"
    end
  end

  self.class.new(self, dataset.where(clause).qualify)
end

#multi_criteria_filter(criteria) ⇒ Persistor

Implement a multicriteria filter for a Sequel::Persistor. Value can be either a String, an Array or a Hash. Strings and Arrays are normal filters, whereas Hashes correspond to a joined search. The criteria will apply to the joined object corresponding to the key.

Parameters:

  • Hash<String, (Hash<String, Object > criteria) —

    Object > criteria

Returns:



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# File 'lib/lims-core/persistence/sequel/filters.rb', line 19

def multi_criteria_filter(criteria)
  # We need to create the adequat dataset.
  dataset = __multi_criteria_filter(criteria).dataset
  # As the dataset can include join, we need to select only the columns
  # corresponding to the persistor
  self.class.new(self, dataset.qualify(table_name).distinct())
end