Class: CqlRuby::CqlGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/cql_ruby/cql_generator.rb

Overview

A generator that produces random CQL queries. <P> Why is that useful? Mainly to produce test-cases for CQL parsers (including the CQLParser class in this package): you can generate a random search tree, render it to XCQL and remember the result. Then decompile the tree to CQL, feed the generated CQL to the parser of your choice, and check that the XCQL it comes up with is the same what you got from your initial rendering. <P> This code is based on the same grammar as the CQLParser class in this distribution - there is a generate_x() method for each grammar element X.

See Also:

  • href="http://zing.z3950.org/cql/index.html" >http://zing.z3950.org/cql/index.html

Version:

  • $Id: CQLGenerator.java,v 1.9 2007/07/03 15:41:35 mike Exp $

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(params) ⇒ CqlGenerator

Returns a new instance of CqlGenerator.



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# File 'lib/cql_ruby/cql_generator.rb', line 22

def initialize( params )
  @debug_mode = params[ :debug ] || false
  @params = params
  srand( params[ :seed ] ) if params and params[ :seed ]
end

Instance Attribute Details

#debug_mode ⇒ Object

Returns the value of attribute debug_mode.



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# File 'lib/cql_ruby/cql_generator.rb', line 20

def debug_mode
  @debug_mode
end

#params ⇒ Object

Returns the value of attribute params.



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# File 'lib/cql_ruby/cql_generator.rb', line 20

def params
  @params
end

#rnd ⇒ Object

Returns the value of attribute rnd.



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# File 'lib/cql_ruby/cql_generator.rb', line 20

def rnd
  @rnd
end

Instance Method Details

#debug(s) ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 28

def debug( s )
  puts( "DEBUG: #{s}" ) if @debug_mode
end

#generate_base_relation ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 84

def generate_base_relation
  return "=" if maybe( :equals_relation )
  return generate_numeric_relation if maybe( :numeric_relation )
  case rand(3)
    when 0 then index = "exact"
    when 1 then index = "all"
    when 2 then index = "any"
  end
  index
end

#generate_cql_query ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 32

def generate_cql_query
  return generate_search_clause  unless maybe( :complex_query )
  
  node1 = generate_cql_query
  node2 = generate_search_clause
  
  if maybe( :proxOp ) 
    # TODO: generate proximity nodes
  else
    case rand( 3 )
    when 0 then return CqlAndNode.new( node1, node2, ModifierSet.new( "and" ) )
    when 1 then return CqlOrNode.new( node1, node2, ModifierSet.new( "or" ) )
    when 2 then return CqlNotNode.new( node1, node2, ModifierSet.new( "or" ) )
    end      
  end
  
  generate_search_clause
end

#generate_index ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 61

def generate_index
  if rand(2) == 0 
    case rand(3)
      when 0 then index = "dc.author"
      when 1 then index = "dc.title"
      when 2 then index = "dc.subject"
    end
  else
    case rand(4)
      when 0 then index = "bath.author"
      when 1 then index = "bath.title"
      when 2 then index = "bath.subject"
      when 3 then index = "foo>bar"
    end
  end
  index
end

#generate_numeric_relation ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 110

def generate_numeric_relation
  case rand(6)
    when 0 then return "<"
    when 1 then return ">"
    when 2 then return "<="
    when 3 then return ">="
    when 4 then return "<>"
    when 5 then return "="
  end
end

#generate_relation ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 79

def generate_relation
  base = generate_base_relation
  CqlRelation.new( base )
end

#generate_search_clause ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 51

def generate_search_clause
  return generate_cql_query if maybe( :complex_clause )
  
  index = generate_index
  relation = generate_relation
  term = generate_term
  
  CqlTermNode.new( index, relation, term )
end

#generate_term ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 95

def generate_term
  case rand(10)
    when 0 then return "cat"
    when 1 then return "\"cat\""
    when 2 then return "comp.os.linux"
    when 3 then return "xml:element"
    when 4 then return "<xml.element>"
    when 5 then return "prox/word/>=/5"
    when 6 then return ""
    when 7 then return "frog fish"
    when 8 then return "the complete dinosaur"
    when 9 then return "foo*bar"
  end
end

#maybe(key) ⇒ Object 



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# File 'lib/cql_ruby/cql_generator.rb', line 121

def maybe( key )
  probability = @params[ key ] || ".1"
  
  dice = rand
  threshold = probability.to_f
  res = dice < threshold
  
  debug( "dice=#{dice} vs #{threshold} = #{res.to_s}" )
  res
end