Module: RDF::AssociatedProperty

Includes:
Enumerable
Defined in:
lib/active_rdf/objectmanager/property.rb

Overview

Provides methods for accessing property values when @subject is set

Instance Method Summary collapse

Instance Method Details

#+(obj) ⇒ Object

Returns a new array with the object appended, or the objects values if obj.respond_to? :to_ary



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# File 'lib/active_rdf/objectmanager/property.rb', line 85

def +(obj)
  to_a + [*obj]
end

#-(obj) ⇒ Object

Returns a new array with the object removed



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# File 'lib/active_rdf/objectmanager/property.rb', line 90

def -(obj)
  to_a - [*obj]
end

#==(other) ⇒ Object Also known as: eql? 



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# File 'lib/active_rdf/objectmanager/property.rb', line 94

def ==(other)
  if other.respond_to?(:to_ary)
    Set.new(other) == Set.new(to_a)
  else
    arr = to_a
    if arr.size == 1
      other == arr[0] || super
    else
      super
    end
  end
end

#[](md5_or_value) ⇒ Object Also known as: at

Value reference. Retrieves a copy of the value by the key or value. Returns nil if not found.



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# File 'lib/active_rdf/objectmanager/property.rb', line 68

def [](md5_or_value)
  unless md5_or_value.nil?
    arr = to_a
    arr.find{|value| value == md5_or_value} || arr.find{|value| get_key(value) == md5_or_value}
  end
end

#[]=(md5_or_value, new_value) ⇒ Object

Selective value replacement. Replaces the value given by key or value. Raises IndexError if value not found.

Raises:

  • (IndexError) 


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# File 'lib/active_rdf/objectmanager/property.rb', line 77

def []=(md5_or_value,new_value)
  value = self[md5_or_value]
  raise IndexError, "Couldn't find existing value to replace: #{md5_or_value}" unless value
  ActiveRDF::FederationManager.delete(@subject, self.property, value)
  add(new_value)
end

#add(*args) ⇒ Object

Append. Adds the given object(s) to the values for this property belonging to @subject This expression returns the property itself, so several appends may be chained together.



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# File 'lib/active_rdf/objectmanager/property.rb', line 110

def add(*args)
  args.each do |arg|
    if arg.respond_to?(:to_ary)
      arg.to_ary.each {|item| ActiveRDF::FederationManager.add(@subject, self.property, item)}
    else
      ActiveRDF::FederationManager.add(@subject, self.property, arg)
    end
  end
  self
end

#clear ⇒ Object

Removes all values



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# File 'lib/active_rdf/objectmanager/property.rb', line 122

def clear
  ActiveRDF::FederationManager.delete(@subject, self.property)
  self
end

#collect!(&block) ⇒ Object Also known as: map!

Invokes the block once for each value, replacing the value with the value returned by block



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# File 'lib/active_rdf/objectmanager/property.rb', line 128

def collect!(&block)
  to_a.each do |item|
    new_item = yield(item)
    delete(item)
    add(new_item)
  end
  self
end

#context(context = nil) ⇒ Object

Returns the context for the property if context is nil. Returns a new RDF::Property object with the @context value set if context is provided see also #lang, #datatype



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# File 'lib/active_rdf/objectmanager/property.rb', line 141

def context(context = nil)
  if context.nil?
    @context
  else
    property_with_context = self.dup
    property_with_context.context = context
    property_with_context
  end
end

#context=(context) ⇒ Object

Sets context for this property



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# File 'lib/active_rdf/objectmanager/property.rb', line 152

def context=(context)
  @context = context
end

#datatype(type = nil) ⇒ Object

Returns the datatype if type is nil. Returns a new RDF::Property object with the @datatype set if type is provided see also #context, #lang



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# File 'lib/active_rdf/objectmanager/property.rb', line 159

def datatype(type = nil)
  if type.nil?
    @datatype
  else
    property_with_datatype = dup
    property_with_datatype.datatype = type
    property_with_datatype
  end
end

#datatype=(type) ⇒ Object

Sets datatype for this property



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# File 'lib/active_rdf/objectmanager/property.rb', line 170

def datatype=(type)
  @datatype = type
end

#delete(md5_or_value) ⇒ Object

Deletes value given by key or value. If the item is not found, returns nil. If the optional code block is given, returns the result of block if the item is not found



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# File 'lib/active_rdf/objectmanager/property.rb', line 176

def delete(md5_or_value)
  value = self[md5_or_value]
  if value
    ActiveRDF::FederationManager.delete(@subject, self.property, value)
    value
  elsif block_given?
    yield
  end
end

#delete_if(&block) ⇒ Object

Deletes every value for which block evaluates to true



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# File 'lib/active_rdf/objectmanager/property.rb', line 187

def delete_if(&block)  # :yields: key, value
  reject!(&block)
  self
end

#each(&block) ⇒ Object Also known as: each_value

Calls block once for each value, passing a copy of the value as a parameter



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# File 'lib/active_rdf/objectmanager/property.rb', line 193

def each(&block)  # :yields: value
  q = ActiveRDF::Query.new.distinct(:o).where(@subject,self,:o,@context)
  if @lang and !@datatype
    q.lang(:o,@lang,@exact_lang)
  elsif @datatype and !@lang
    q.datatype(:o, @datatype)
  elsif @lang and @datatype
    raise ActiveRdfError, "@datatype and @lang may not both be set"
  end
  q.execute(&block)
  self
end

#each_key(&block) ⇒ Object

Calls block once for each value, passing the key as a parameter



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# File 'lib/active_rdf/objectmanager/property.rb', line 208

def each_key(&block)  # :yields: key
  keys.each(&block)
  self
end

#each_pair(&block) ⇒ Object

Calls block once for each value, passing the key and value as a parameters See also #to_h



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# File 'lib/active_rdf/objectmanager/property.rb', line 215

def each_pair(&block)  # :yields: key, value
  each{|value| yield get_key(value), value}
  self
end

#empty? ⇒ Boolean Also known as: blank?

Returns true if the property contains no values

Returns:

  • (Boolean) 


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# File 'lib/active_rdf/objectmanager/property.rb', line 221

def empty?
  to_a.empty?
end

#fetch(md5, default = nil, &block) ⇒ Object

Returns a value from the property for the given key. If the key can’t be found, there are several options: With no other arguments, it will raise an IndexError exception; if default is given, then that will be returned; if the optional code block is specified, then that will be run and its result returned.



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# File 'lib/active_rdf/objectmanager/property.rb', line 229

def fetch(md5, default = nil, &block)
  val = self[md5]
  if val
    val
  else
    if block_given?
      yield md5
    elsif default
      default
    else
      raise IndexError, "could not find #{md5}"
    end
  end
end

#include?(obj) ⇒ Boolean Also known as: value?, has_value?

Returns true if the given key or value is present

Returns:

  • (Boolean) 


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# File 'lib/active_rdf/objectmanager/property.rb', line 245

def include?(obj)
  !!self[obj]
end

#index(obj) ⇒ Object

Returns the key for a given value. If not found, returns nil.



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# File 'lib/active_rdf/objectmanager/property.rb', line 252

def index(obj)
  value = to_a.find{|val| obj == val}
  get_key(value) if value
end

#inspect ⇒ Object

Return the value(s) of this property as a string.



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# File 'lib/active_rdf/objectmanager/property.rb', line 258

def inspect
  "#<RDF::Property #{abbr} [#{to_a.collect{|obj| obj.inspect}.join(", ")}]>"
end

#keys ⇒ Object

Returns a new array populated with the keys to the values



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# File 'lib/active_rdf/objectmanager/property.rb', line 263

def keys
  collect{|value| get_key(value)}
end

#lang(tag = nil, exact = true) ⇒ Object

Returns the language tag and the match settings for the property if tag is nil. Returns a new RDF::Property object with the @lang value set if tag is provided see also #context, #datatype



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# File 'lib/active_rdf/objectmanager/property.rb', line 270

def lang(tag = nil, exact = true)
  if tag.nil?
    [@lang,@exact_lang]
  else
    property_with_lang = RDF::Property.new(self, @subject)
    property_with_lang.lang = tag, exact
    property_with_lang
  end
end

#lang=(*args) ⇒ Object

Sets lang and match settings



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# File 'lib/active_rdf/objectmanager/property.rb', line 281

def lang=(*args)
  args.flatten!
  @lang = args[0].sub(/^@/,'')
  @exact_lang = truefalse(args[1],true)
end

#length ⇒ Object Also known as: size

Returns the number of values assigned to this property for this @subject



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# File 'lib/active_rdf/objectmanager/property.rb', line 288

def length
  to_a.length
end

#only ⇒ Object

Ensure the return of only one value assigned to this property for this @subject. If more than 1 value is found, ActiveRdfError is thrown.

Raises:



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# File 'lib/active_rdf/objectmanager/property.rb', line 295

def only
  entries = self.entries
  raise ActiveRDF::ActiveRdfError if entries.size > 1
  entries[0]
end

#reject!(&block) ⇒ Object

Equivalent to Property#delete_if, but returns nil if no changes were made



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# File 'lib/active_rdf/objectmanager/property.rb', line 302

def reject!(&block)  # :yields: key, value
  change = false
  each_pair do |key, value|
    if yield(key, value)
      delete(value)
      change = true
    end
  end
  self if change
end

#replace(new) ⇒ Object

Value replacement. Replaces all current value(s) with the new value



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# File 'lib/active_rdf/objectmanager/property.rb', line 314

def replace(new)
  clear
  add(new)
  self
end

#to_h ⇒ Object

Returns a hash of copies of all values with indexes. Changes to this hash will not effect the underlying values. Use #add or #replace to persist changes. See also #each_pair



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# File 'lib/active_rdf/objectmanager/property.rb', line 327

def to_h
  hash = {}
  to_a.each do |value|
    hash[get_key(value)] = value
  end
  hash
end

#values_at(*args) ⇒ Object

Return an array containing the values for the given keys.



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# File 'lib/active_rdf/objectmanager/property.rb', line 336

def values_at(*args)
  args.collect{|md5| self[md5]}
end