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# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
module AWS
class SimpleDB
# Represents a single named item attribute in SimpleDB.
class Attribute
include Core::Model
include Enumerable
include ConsistentReadOption
include PutAttributes
include DeleteAttributes
# @api private
def initialize item, name, options = {}
@item = item
@name = name
super
end
# @return [Item] The item this attribute belongs to.
attr_reader :item
# @return [String] The name of this attribute.
attr_reader :name
# Sets all values for this attribute, replacing current values.
#
# @example Setting a list of values
#
# attributes['colors'].set 'red', 'blue', 'green'
#
# @example Setting an array of values
#
# attributes['colors'].set ['red', 'blue']
#
# @param [String] values A list of attribute values to set.
# @return [nil]
def set *values
put(values, true)
nil
end
# Appends values to this attribute. Duplicate values are ignored
# by SimpleDB.
#
# @example Adding a list of values
#
# attributes['colors'].add 'red', 'blue', 'green'
#
# @example Adding an array of values
#
# attributes['colors'].add ['red', 'blue']
#
# @param [String] values A list of attribute values to add.
# @return [nil]
def add *values
put(values, false)
nil
end
alias_method :<<, :add
# Deletes this attribute or specific values from this attribute.
#
# @example Delete the attribute and all of its values
#
# item.attributes['color'].delete
#
# @example Delete specific attribute values
#
# item.attributes['color'].delete('red', 'blue')
#
# @param values One ore more values to remove from this attribute.
# If values is empty, then all attribute values are deleted
# (which deletes this attribute).
# @return [nil]
def delete *values
expect_opts = values.pop if values.last.kind_of?(Hash)
if values.empty?
delete_named_attributes(name, expect_opts || {})
else
delete_attribute_values(Hash[[[name, values]]].
merge(expect_opts || {}))
end
nil
end
# Yields once for each value on this attribute.
#
# @yield [attribute_value] Yields once for each domain in the account.
# @yieldparam [String] attribute_value
# @param [Hash] options
# @option options [Boolean] :consistent_read (false) A consistent read
# returns values that reflects all writes that received a successful
# response prior to the read.
# @return [nil]
def each options = {}, &block
resp = client.get_attributes(
:domain_name => item.domain.name,
:item_name => item.name,
:attribute_names => [name],
:consistent_read => consistent_read(options))
resp.attributes.each do |attribute|
yield(attribute.value)
end
nil
end
# Returns all values for this attribute as an array of strings.
#
# @example
# item.attributes['ratings'].values
# #=> ['5', '3', '4']
#
# @param [Hash] options
# @option options [Boolean] :consistent_read (false) A consistent read
# returns values that reflects all writes that received a successful
# response prior to the read.
# @return [Array<String>] An array of attribute values
def values options = {}
values = []
self.each(options) do |value|
values << value
end
values
end
# @api private
protected
def put values, replace
expect_opts = values.pop if values.last.kind_of?(Hash)
do_put(attribute_hashes(Hash[[[name, values]]],
replace),
expect_opts || {})
end
end
end
end
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