Class: Criteria

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

Overview

Criteria is a collection of Criterion as well as additional constraints regarding the order, limit and offset

see the readme for usage examples.

Defined Under Namespace

Modules: VERSION Classes: Association, ClassHeirarchyContext, Column, Criterion, ManyToOneAssociation, NotCriterion, OneToManyAssociation, Order

Constant Summary collapse

@@debug = 
false

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(clazz = nil, def_operator = :AND) ⇒ Criteria

Create a new criteria, optionally pass in a Criterion object You can also pass a block, and self will be yielded



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# File 'lib/criteria.rb', line 30

def initialize(clazz=nil, def_operator=:AND) # :yields: self
  @associations = []
  @criteria = []
  @operator = def_operator
  # @and = []
  # @or = []
  @order_by = []
  @group_by = []
  @select = []
  @limit = nil
  @offset = nil    
  @joins = []
  # @default_operator = :or
@clazz = clazz if clazz.is_a? Class

# Add the supplied criterion if it is defined
  # add(clazz) if clazz.is_a? Criterion
  # add(c) if c.is_a? Criterion 

  yield(self) if block_given?
end

Instance Attribute Details

#limit ⇒ Object

, :default_operator #, :operator



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# File 'lib/criteria.rb', line 18

def limit
  @limit
end

#offset ⇒ Object

, :default_operator #, :operator



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# File 'lib/criteria.rb', line 18

def offset
  @offset
end

Class Method Details

.debug ⇒ Object 



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# File 'lib/criteria.rb', line 20

def self.debug
  @@debug
end

.debug=(val) ⇒ Object 



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# File 'lib/criteria.rb', line 24

def self.debug=(val)
  @@debug=val
end

Instance Method Details

#&(criterion) ⇒ Object

AND this with another criterion



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# File 'lib/criteria.rb', line 152

def &(criterion)
  self.and(criterion)
end

#<<(c) ⇒ Object 



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# File 'lib/criteria.rb', line 107

def <<(c)
  raise "<< does not accept a block, perhaps you were trying to pass it to Criteria.new?" if block_given?
  add(c)
end

#add(c = nil, operator = @operator, opts = {}, &block) ⇒ Object 



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# File 'lib/criteria.rb', line 112

def add(c=nil, operator=@operator, opts={}, &block)
  
  # If we are using an :or and this is an :and, or vice versa, then create a new sub-criteria to contain it
  if operator!=@operator
    newcriteria = Criteria.new(bound_class, @operator==:AND ? :OR : :AND)
    newcriteria << self
    newcriteria.add(c, operator, opts, &block)
    return newcriteria
  end
  
  # If the criterion object is nil, and there is a block given, yield a new Criteria to the block
  c = yield(self) if c.nil? and block_given?
  
  raise "Supplied argument is nil" if c.nil?
    
  # puts "Criteria.add: #{self} #{operator} #{c}"
  # If the c is a column, moan about it and refuse to continue
  if c.is_a? Column
    raise "You cannot directly #{operator.to_s.upcase} an instanceof Column, you must call some sort of expression (eq, ne, gt, ge, etc) on it."
  end
  
  # If the criterion is bound to a class and this is also bound to a class we try and find an applicable association for the criterion
  if !c.bound_class.nil? and !@clazz.nil?
    # puts " + #{c.bound_class} AND #{@clazz}"
    a=@clazz.find_associations_with(c.bound_class)
    
    if a.size>1 and a.include? opts[:via]
      @associations << opts[:via]
    elsif a.size==0
      # do nothing
    else
      @associations << a.first
    end
  end
  
  @criteria << c
  self
end

#all_criteria ⇒ Object

Returns an unmodifiable array of all AND’d and OR’d criteria



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# File 'lib/criteria.rb', line 60

def all_criteria
  and_criteria+or_criteria
end

#and(c = nil, &block) ⇒ Object

AND a criterion with the existing Criteria



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# File 'lib/criteria.rb', line 98

def and(c=nil, &block)
  add(c, :AND, &block)
end

#and_criteria ⇒ Object

Return a modifiable array of AND’d criteria



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# File 'lib/criteria.rb', line 65

def and_criteria
  if operator==:AND
    @criteria
  else
    @other_criteria.and_criteria
  end
end

#associations ⇒ Object 



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# File 'lib/criteria.rb', line 200

def associations
  out = @associations
  @criteria.each do |c| 
    out+=c.associations
  end
  out
end

#bound_class ⇒ Object

If this Criteria was created by passing an ActiveRecord::Base subclass as the first argument to the constructor, then this will return that class. Criteria that are bound to classes can perform additional introspection to resolve association dependencies



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# File 'lib/criteria.rb', line 55

def bound_class
  @clazz
end

#columns ⇒ Object

Return a unique list of column objects that are referenced in this query



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# File 'lib/criteria.rb', line 184

def columns
  columns = []
  @criteria.each do |c|
   c.columns.each do |c2|
     columns << c2
   end
  end 
  columns.uniq
end

#count ⇒ Object 



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# File 'lib/criteria.rb', line 212

def count
  @clazz.count(self)
end

#first ⇒ Object 



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# File 'lib/criteria.rb', line 216

def first
  @clazz.find(:first, self)
end

#group_by ⇒ Object

Get the collection of columns to group by



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# File 'lib/criteria.rb', line 88

def group_by
  @group_by
end

#inspect(indent = 0) ⇒ Object 



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# File 'lib/criteria.rb', line 267

def inspect(indent=0)
  indent_str = " " * indent
  "(\n" + @criteria.collect do |c| 
    "#{" " * (indent+1)}#{@operator} #{c.inspect(indent+1)}"
  end.join("\n") + "\n#{indent_str})"
end

#list ⇒ Object 



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# File 'lib/criteria.rb', line 208

def list
  @clazz.find(:all, self)
end

#or(c = nil, &block) ⇒ Object

OR a criterion with the existing Criteria



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# File 'lib/criteria.rb', line 103

def or(c=nil, &block)
  add(c, :OR, &block)
end

#or_criteria ⇒ Object

Return a modifiable array of OR’d criteria



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# File 'lib/criteria.rb', line 74

def or_criteria
  if operator==:OR
    @criteria
  else
    @other_criteria.or_criteria
  end
end

#order_by ⇒ Object

Get the collection of Order objects to order by



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# File 'lib/criteria.rb', line 93

def order_by
  @order_by
end

#select ⇒ Object

Returns an array of column’s to be selected



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# File 'lib/criteria.rb', line 83

def select
  @select
end

#tables ⇒ Object

Get a read-only array of all the table names that will be included in this query



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# File 'lib/criteria.rb', line 196

def tables
  columns.collect {|c| c.table_name }.uniq
end

#to_group_by_sql ⇒ Object 



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# File 'lib/criteria.rb', line 175

def to_group_by_sql
  @group_by.size>0 ? @group_by.collect {|g| g.to_s}.join(",") : nil
end

#to_hash ⇒ Object

FIXME: this returns a list of table names in :include, whereas it should contain the relationship names



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# File 'lib/criteria.rb', line 251

def to_hash
  {
    :include => self.associations,
    :conditions => self.to_where_sql,
    :limit => self.limit,
    :offset => self.offset,
    :order => self.to_order_by_sql,
    :group => self.to_group_by_sql,
    :select => self.to_select_sql
  }
end

#to_order_by_sql ⇒ Object 



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# File 'lib/criteria.rb', line 171

def to_order_by_sql
  @order_by.size>0 ? @order_by.collect {|o| o.to_s}.join(",") : nil
end

#to_s ⇒ Object 



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# File 'lib/criteria.rb', line 263

def to_s
  "Criteria(#{to_hash.inspect})"
end

#to_select_sql ⇒ Object 



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# File 'lib/criteria.rb', line 179

def to_select_sql
  @select.size>0 ? @select.collect{|s| s.to_s}.join(",") : nil
end

#to_where_sql ⇒ Object

Convert the AND and OR statements into the WHERE SQL



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# File 'lib/criteria.rb', line 162

def to_where_sql
  if @criteria.size>0
    out = @criteria.collect {|c| "#{c.to_where_sql}"}.join(" #{@operator} ")
    "(#{out})"
  else
    ""
  end
end

#|(criterion) ⇒ Object

OR this with another criterion



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# File 'lib/criteria.rb', line 157

def |(criterion)
  self.or(criterion)
end