class AWS::SimpleDB::AttributeCollection

@return [Item] The item this collection belongs to.

@param [Item] The item to create an attribute collection for. @return [AttributeCollection]

# File lib/aws/simple_db/attribute_collection.rb, line 26
def initialize item, options = {}
  @item = item
  super
end

Retuns an Attribute with the given name.

@note This does not make a request to SimpleDB.

You can ask for any attribute by name. The attribute may or may not actually exist in SimpleDB.

@example Get an attribute by symbol or string name

colors = item.attributes[:colors]
colors = item.attributes['colors']

@param [String, Symbol] attribute_name name of the attribute to get. @return [Item] An item with the given name.

# File lib/aws/simple_db/attribute_collection.rb, line 46
def [] attribute_name
  Attribute.new(item, attribute_name.to_s)
end

Sets the values for a given attribute.

@example Replace all of the values for the named attribute.

item.attributes[:color] = 'red', 'blue'

@return This method returns the values passed to it.

# File lib/aws/simple_db/attribute_collection.rb, line 55
def []= attribute_name, *values
  self[attribute_name].set(*values)
end

Adds values to attributes on the {item}.

The attributes_hash should have attribute names as keys. The hash values should be either strings or arrays of strings.

@example

item.attributes.add(
  'colors' => ['red', 'blue'],  
  'category' => 'clearance')

@param attribute_hash @return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 154
def add attributes
  do_put(attribute_hashes(attributes, false), attributes)
end

Delete one or more attributes from {item}.

@example Delete a list of attributes by name

item.attributes.delete 'size', 'color'
item.attributes.delete %w(size color)

@param attribute_names An array or list of attribute names to delete. @return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 210
def delete *args
  if args.size == 1 and args.first.kind_of?(Hash)
    delete_attribute_values(args.first)
  else
    delete_named_attributes(*args)
  end
  nil
end

Yields all attribute for this item.

@example Getting all attributes for an item

item.attributes.each do |attribute|
  puts attribute.name
end

@yield [attribute] Yields once for every attribute

on the item.  Yields each attribute only one time, even it
has multiple values.

@yieldparam [Attribute] attribute @param [Hash] options @option options [Boolean] :consistent_read (false) Causes this

method to yield the most current attributes for this item.

@return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 108
def each options = {}, &block
  yielded = {}
  each_value(options) do |attribute_name, attribute_value| 
    unless yielded[attribute_name]
      attribute = self[attribute_name]
      yield(attribute)
      yielded[attribute_name] = true
    end
  end
  nil
end

Yields all attribute values with their names.

@example Getting all values for an item

item.attributes.each_value do |name, value|
  puts "#{name}: #{value}"
end

@yield [attribute_name, attribute_value] Yields once for every

attribute value on the item.

@yieldparam [String] attribute_name @yieldparam [String] attribute_value @param [Hash] options @option options [Boolean] :consistent_read (false) Causes this

method to yield the most current attributes for this item.

@return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 75
def each_value options = {}, &block

  list = client.get_attributes(
    :domain_name => item.domain.name,
    :item_name => item.name,
    :consistent_read => consistent_read(options))

  list.attributes.each do |attribute|
    attribute_name = attribute.name
    attribute_value = attribute.value
    yield(attribute_name, attribute_value)
  end

  nil

end

Perform a mixed update of added and replace attribues.

item.attributes.put(
  :add => { 'colors' => %w(green blue), 'tags' => 'cool' }
  :replace => { 'quantity' => 5 }
)

@param [Hash] options @option options [Hash] :add A hash of attribute names and values to

append to this item.

@option options [Hash] :replace A hash of attribute names and values to

add to this item.  If there are currently attributes of the same
name they will be replaced (not appended to).

@option options [Hash] :replace @return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 173
def put options = {}
  add = options[:add] || {}
  replace = options[:replace] || {}
  attributes = attribute_hashes(add, false)
  attributes += attribute_hashes(replace, true)
  do_put(attributes, options)
end

Replaces attributes for the {item}.

The attributes_hash should have attribute names as keys. The hash values should be either strings or arrays of strings.

Attributes not named in this hash are left alone. Attributes named in this hash are replaced.

@example

item.attributes.set(
  'colors' => ['red', 'blue'],  
  'category' => 'clearance')

@param [Hash] attributes @return [nil]

# File lib/aws/simple_db/attribute_collection.rb, line 136
def replace attributes
  do_put(attribute_hashes(attributes, true), attributes)
end

Returns a hash of all attributes (names and values). The attribute names are strings and the values are arrays of strings.

@example

item.attributes.to_h
#=> { 'colors' => ['red','blue'], 'size' => ['large'] }

@param [Hash] options @option options [Boolean] :consistent_read (false) Causes this

method to return the most current attributes values.

@return [Hash]

# File lib/aws/simple_db/attribute_collection.rb, line 193
def to_h options = {}
  hash = {}
  each_value(options) do |attribute_name,attribute_value|
    hash[attribute_name] ||= []
    hash[attribute_name] << attribute_value
  end
  hash
end