class Google::Cloud::Spanner::Database::List

Database::List is a special case Array with additional values.

Attributes

token[RW]

If not empty, indicates that there are more records that match the request and this value should be passed to continue.

Public Class Methods

from_grpc(grpc, service, instance_id, max = nil) click to toggle source

@private New Database::List from a `Google::Cloud::Spanner::Admin::Database::V1::ListDatabasesResponse` object.

# File lib/google/cloud/spanner/database/list.rb, line 147
def self.from_grpc grpc, service, instance_id, max = nil
  databases = List.new(Array(grpc.databases).map do |database|
    Database.from_grpc database, service
  end)
  databases.instance_variable_set :@instance_id, instance_id
  token = grpc.next_page_token
  token = nil if token == "".freeze
  databases.instance_variable_set :@token,   token
  databases.instance_variable_set :@service, service
  databases.instance_variable_set :@max,     max
  databases
end
new(arr = []) click to toggle source

@private Create a new Database::List with an array of Database instances.

Calls superclass method
# File lib/google/cloud/spanner/database/list.rb, line 34
def initialize arr = []
  super arr
end

Public Instance Methods

all(request_limit: nil, &block) click to toggle source

Retrieves remaining results by repeatedly invoking {#next} until {#next?} returns `false`. Calls the given block once for each result, which is passed as the argument to the block.

An Enumerator is returned if no block is given.

This method will make repeated API calls until all remaining results are retrieved. (Unlike `#each`, for example, which merely iterates over the results returned by a single API call.) Use with caution.

@param [Integer] request_limit The upper limit of API requests to

make to load all databases. Default is no limit.

@yield [database] The block for accessing each database. @yieldparam [Database] database The database object.

@return [Enumerator]

@example Iterating each database by passing a block:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
databases.all do |database|
  puts database.database_id
end

@example Using the enumerator by not passing a block:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
all_database_ids = databases.all.map do |database|
  database.database_id
end

@example Limit the number of API calls made:

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
databases.all(request_limit: 10) do |database|
  puts database.database_id
end
# File lib/google/cloud/spanner/database/list.rb, line 126
def all request_limit: nil, &block
  request_limit = request_limit.to_i if request_limit
  unless block_given?
    return enum_for :all, request_limit: request_limit
  end
  results = self
  loop do
    results.each(&block)
    if request_limit
      request_limit -= 1
      break if request_limit.negative?
    end
    break unless results.next?
    results = results.next
  end
end
next() click to toggle source

Retrieve the next page of databases.

@return [Database::List]

@example

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
if databases.next?
  next_databases = databases.next
end
# File lib/google/cloud/spanner/database/list.rb, line 70
def next
  return nil unless next?
  ensure_service!
  options = { token: token, max: @max }
  grpc = @service.list_databases @instance_id, **options
  self.class.from_grpc grpc, @service, @max
end
next?() click to toggle source

Whether there is a next page of databases.

@return [Boolean]

@example

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new

databases = spanner.databases "my-instance"
if databases.next?
  next_databases = databases.next
end
# File lib/google/cloud/spanner/database/list.rb, line 52
def next?
  !token.nil?
end

Protected Instance Methods

ensure_service!() click to toggle source

Raise an error unless an active service is available.

# File lib/google/cloud/spanner/database/list.rb, line 164
def ensure_service!
  raise "Must have active connection" unless @service
end