Class: Ferret::Index::DocumentWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/ferret/index/document_writer.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(directory, analyzer, similarity, max_field_length, term_index_interval = IndexWriter::DEFAULT_TERM_INDEX_INTERVAL) ⇒ DocumentWriter

directory

The directory to write the document information to

analyzer

The analyzer to use for the document

similarity

The Similarity function writer.similarity

max_field_length

The maximum number of tokens a field may have writer.max_field_length

term_index_interval

The interval of terms in the index writer.max_field_length



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# File 'lib/ferret/index/document_writer.rb', line 17

def initialize(directory,
               analyzer,
               similarity,
               max_field_length,
               term_index_interval = IndexWriter::DEFAULT_TERM_INDEX_INTERVAL) 
  @directory = directory
  @analyzer = analyzer
  @similarity = similarity
  @max_field_length = max_field_length
  @term_index_interval = term_index_interval

  # Keys are Terms, values are Postings.
  # Used to buffer a document before it is written to the index.
  @posting_table = {}

  @term_buffer = Term.new("", "")
end

Instance Attribute Details

#info_stream=(value) ⇒ Object (writeonly)

If non-nil, a message will be printed to this if max_field_length is reached.



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# File 'lib/ferret/index/document_writer.rb', line 8

def info_stream=(value)
  @info_stream = value
end

Instance Method Details

#add_document(segment, doc) ⇒ Object 



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# File 'lib/ferret/index/document_writer.rb', line 35

def add_document(segment, doc)
       
  # write field names
  @field_infos = FieldInfos.new()
  @field_infos << doc
  @field_infos.write_to_dir(@directory, segment + ".fnm")

  # write field values
  fields_writer = FieldsWriter.new(@directory, segment, @field_infos)
  begin 
    fields_writer.add_document(doc)
  ensure 
    fields_writer.close()
  end

  # invert doc into posting_table
  @posting_table.clear();                    # clear posting_table
  arr_size = @field_infos.size
  @field_lengths = Array.new(arr_size, 0)    # init field_lengths
  @field_positions = Array.new(arr_size, 0)  # init field_positions
  @field_offsets = Array.new(arr_size, 0)    # init field_offsets
  @field_boosts = Array.new(arr_size, doc.boost) # init field_boosts

  invert_document(doc)

  # sort posting_table into an array
  postings = sort_posting_table()

  #    for (int i = 0; i < postings.length; i += 1) 
  #      Posting posting = postings[i]
  #      print(posting.term)
  #      print(" freq=" + posting.freq)
  #      print(" pos=")
  #      print(posting.positions[0])
  #      for (int j = 1; j < posting.freq; j += 1)
  #        print("," + posting.positions[j])
  #      puts("")
  #    end

  # write postings
  write_postings(postings, segment)

  # write norms of indexed fields
  write_norms(segment)

end