Class: Treequel::Filter::SimpleItemComponent

Inherits:

ItemComponent

Object
Component
ItemComponent
Treequel::Filter::SimpleItemComponent

show all

Includes:: Constants::Patterns

Defined in:: lib/treequel/filter.rb

Overview

A simple (attribute=value) component

simple     = attr filtertype value
filtertype = equal / approx / greater / less
equal      = "="
approx     = "~="
greater    = ">="
less       = "<="

Constant Summary collapse

FILTERTYPE_OP = The valid values for filtertype and the equivalent operator

{
	:equal   => '=',
	:approx  => '~=',
	:greater => '>=',
	:less    => '<=',
}

FILTEROP_NAMES = Inverse of the FILTERTYPE_OP mapping (symbol -> name)

FILTERTYPE_OP.invert.freeze

FILTER_SPLIT_REGEXP = A regex that matches any of the ‘simple’ operators.

Regexp.new( '(' + FILTERTYPE_OP.values.join('|') + ')' )

Constants included from Constants::Patterns

Instance Attribute Summary collapse

#attribute ⇒ Object

The name of the item’s attribute.
#filtertype ⇒ Object

The item’s filter type (one of FILTERTYPE_OP.keys).
#value ⇒ Object

The item’s value.

Class Method Summary collapse

.parse_from_string(literal) ⇒ Object

Parse a new SimpleItemComponent from the specified literal.

Instance Method Summary collapse

#filtertype_op ⇒ Object

The operator that is associated with the item’s filtertype.
#initialize(attribute, value, filtertype = :equal) ⇒ SimpleItemComponent constructor

Create a new ‘simple’ item filter component with the given attribute, filtertype, and value.
#to_s ⇒ Object

Stringify the component.

Methods inherited from Component

inherited, #inspect, #promiscuous?

Constructor Details

#initialize(attribute, value, filtertype = :equal) ⇒ `SimpleItemComponent`

Create a new ‘simple’ item filter component with the given attribute, filtertype, and value. The filtertype should be one of: :equal, :approx, :greater, :less

# File 'lib/treequel/filter.rb', line 245

def initialize( attribute, value, filtertype=:equal )
	self.log.debug "creating a new %s %s for %p and %p" %
		[ filtertype, self.class.name, attribute, value ]

	# Handle Sequel :attribute.identifier
	attribute = attribute.value if attribute.respond_to?( :value )

	filtertype = filtertype.to_s.downcase.to_sym
	if FILTERTYPE_OP.key?( filtertype )
		# no-op
	elsif FILTEROP_NAMES.key?( filtertype.to_s )
		filtertype = FILTEROP_NAMES[ filtertype.to_s ]
	else
		raise Treequel::ExpressionError,
			"invalid simple item operator %p" % [ filtertype ]
	end

	@attribute  = attribute
	@value      = value
	@filtertype = filtertype
end

Instance Attribute Details

#attribute ⇒ `Object`

The name of the item’s attribute



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# File 'lib/treequel/filter.rb', line 273

def attribute
  @attribute
end

#filtertype ⇒ `Object`

The item’s filter type (one of FILTERTYPE_OP.keys)



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# File 'lib/treequel/filter.rb', line 279

def filtertype
  @filtertype
end

#value ⇒ `Object`

The item’s value



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# File 'lib/treequel/filter.rb', line 276

def value
  @value
end

Class Method Details

.parse_from_string(literal) ⇒ `Object`

Parse a new SimpleItemComponent from the specified literal.

# File 'lib/treequel/filter.rb', line 228

def self::parse_from_string( literal )
	parts = literal.split( FILTER_SPLIT_REGEXP, 3 )
	unless parts.length == 3
		raise Treequel::ExpressionError,
			"unable to parse %p as a string literal" % [ literal ]
	end

	attribute, operator, value = *parts
	filtertype = FILTEROP_NAMES[ operator ]

	return self.new( attribute, value, filtertype )
end

Instance Method Details

#filtertype_op ⇒ `Object`

The operator that is associated with the item’s filtertype.



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# File 'lib/treequel/filter.rb', line 283

def filtertype_op
	FILTERTYPE_OP[ self.filtertype.to_sym ]
end

#to_s ⇒ `Object`

Stringify the component

# File 'lib/treequel/filter.rb', line 289

def to_s
	# Escape all the filter metacharacters
	escaped_val = self.value.to_s.gsub( UNESCAPED ) do |char|
		'\\' + char.unpack('C*').first.to_s(16)
	end

	return [ self.attribute, self.filtertype_op, escaped_val ].join
end