Class: CassandraObject::Cursor

Inherits:
Object
  • Object
show all
Includes:
Consistency
Defined in:
lib/cassandra_object/cursor.rb

Instance Method Summary collapse

Constructor Details

#initialize(target_class, column_family, key, super_column, options = {}) ⇒ Cursor

Returns a new instance of Cursor.



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# File 'lib/cassandra_object/cursor.rb', line 5

def initialize(target_class, column_family, key, super_column, options={})
  @target_class  = target_class
  @column_family = column_family
  @key           = key.to_s
  @super_column  = super_column
  @options       = options
  @validators    = []
end

Instance Method Details

#connection ⇒ Object 



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# File 'lib/cassandra_object/cursor.rb', line 83

def connection
  @target_class.connection
end

#find(number_to_find) ⇒ Object 



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# File 'lib/cassandra_object/cursor.rb', line 14

def find(number_to_find)
  limit       = number_to_find
  objects     = CassandraObject::Collection.new
  out_of_keys = false

  if start_with = @options[:start_after]
    limit += 1
  else
    start_with = nil
  end
  
  while objects.size < number_to_find && !out_of_keys
    index_results = 
      begin
        CassandraObject::Base.with_connection(@key, :read) do
          connection.get(@column_family, @key, @super_column,
                         count: limit,
                         start: start_with,
                         reversed: @options[:reversed],
                         consistency: target_class.thrift_read_consistency)
        end
      end

    out_of_keys  = index_results.size < limit

    if !start_with.blank?
      index_results.delete(start_with)
    end

    keys = index_results.keys
    values = index_results.values
    
    missing_keys = []
    
    results = values.empty? ? {} : @target_class.multi_get(values)
    results.each do |(key, result)|
      if result.nil?
        missing_keys << key
      end
    end

    unless missing_keys.empty?
      @target_class.multi_get(missing_keys, :quorum=>true).each do |(key, result)|
        index_key = index_results.index(key)
        if result.nil?
          remove(index_key)
          results.delete(key)
        else
          results[key] = result
        end
      end
    end

    results.values.each do |o|
      if @validators.all? {|v| v.call(o) }
        objects << o
      else
        remove(index_results.index(o.key))
      end
    end
    
    start_with = objects.last_column_name = keys.last
    limit = (number_to_find - results.size) + 1
    
  end
  
  return objects
end

#remove(index_key) ⇒ Object 



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# File 'lib/cassandra_object/cursor.rb', line 87

def remove(index_key)
  CassandraObject::Base.with_connection(@key) do
    connection.remove(@column_family, @key, @super_column, index_key, consistency: target_class.thrift_write_consistency)
  end
end

#validator(&validator) ⇒ Object 



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# File 'lib/cassandra_object/cursor.rb', line 93

def validator(&validator)
  @validators << validator
end