The Singleton
module implements the Singleton
pattern.
To use Singleton
, include the module in your class.
class Klass include Singleton # ... end
This ensures that only one instance of Klass can be created.
a,b = Klass.instance, Klass.instance a == b # => true Klass.new # => NoMethodError - new is private ...
The instance is created at upon the first call of Klass.instance().
class OtherKlass include Singleton # ... end ObjectSpace.each_object(OtherKlass){} # => 0 OtherKlass.instance ObjectSpace.each_object(OtherKlass){} # => 1
This behavior is preserved under inheritance and cloning.
This above is achieved by:
Making Klass.new and Klass.allocate private.
Overriding Klass.inherited(sub_klass) and Klass.clone() to ensure that the Singleton
properties are kept when inherited and cloned.
Providing the Klass.instance() method that returns the same object each time it is called.
Overriding Klass._load(str) to call Klass.instance().
Overriding Klass#clone and Klass#dup to raise TypeErrors to prevent cloning or duping.
Singleton
and Marshal
By default Singleton’s _dump(depth)
returns the empty string. Marshalling by default will strip state information, e.g. instance variables and taint state, from the instance. Classes using Singleton
can provide custom _load(str) and _dump(depth) methods to retain some of the previous state of the instance.
require 'singleton' class Example include Singleton attr_accessor :keep, :strip def _dump(depth) # this strips the @strip information from the instance Marshal.dump(@keep, depth) end def self._load(str) instance.keep = Marshal.load(str) instance end end a = Example.instance a.keep = "keep this" a.strip = "get rid of this" a.taint stored_state = Marshal.dump(a) a.keep = nil a.strip = nil b = Marshal.load(stored_state) p a == b # => true p a.keep # => "keep this" p a.strip # => nil
A custom InputMethod class used by XMP
for evaluating string io.
RingFinger
is used by RingServer
clients to discover the RingServer’s TupleSpace
. Typically, all a client needs to do is call RingFinger.primary
to retrieve the remote TupleSpace
, which it can then begin using.
To find the first available remote TupleSpace:
Rinda::RingFinger.primary
To create a RingFinger
that broadcasts to a custom list:
rf = Rinda::RingFinger.new ['localhost', '192.0.2.1'] rf.primary
Rinda::RingFinger
also understands multicast addresses and sets them up properly. This allows you to run multiple RingServers on the same host:
rf = Rinda::RingFinger.new ['239.0.0.1'] rf.primary
You can set the hop count (or TTL) for multicast searches using multicast_hops
.
If you use IPv6 multicast you may need to set both an address and the outbound interface index:
rf = Rinda::RingFinger.new ['ff02::1'] rf.multicast_interface = 1 rf.primary
At this time there is no easy way to get an interface index by name.
WIN32OLE_VARIABLE
objects represent OLE variable information.
WIN32OLE_VARIANT
objects represents OLE variant.
Win32OLE converts Ruby object into OLE variant automatically when invoking OLE methods. If OLE method requires the argument which is different from the variant by automatic conversion of Win32OLE, you can convert the specfied variant type by using WIN32OLE_VARIANT
class.
param = WIN32OLE_VARIANT.new(10, WIN32OLE::VARIANT::VT_R4) oleobj.method(param)
WIN32OLE_VARIANT
does not support VT_RECORD variant. Use WIN32OLE_RECORD
class instead of WIN32OLE_VARIANT
if the VT_RECORD variant is needed.
Certain attributes are required on specific tags in an RSS
feed. If a feed is missing one of these attributes, a MissingAttributeError
is raised.
This exception is raised if the nesting of parsed data structures is too deep.
The InstructionSequence
class represents a compiled sequence of instructions for the Ruby Virtual Machine.
With it, you can get a handle to the instructions that make up a method or a proc, compile strings of Ruby code down to VM instructions, and disassemble instruction sequences to strings for easy inspection. It is mostly useful if you want to learn how the Ruby VM works, but it also lets you control various settings for the Ruby iseq compiler.
You can find the source for the VM instructions in insns.def
in the Ruby source.
The instruction sequence results will almost certainly change as Ruby changes, so example output in this documentation may be different from what you see.
Exception
raised when there is an invalid encoding detected
PrettyPrint::SingleLine
is used by PrettyPrint.singleline_format
It is passed to be similar to a PrettyPrint
object itself, by responding to:
but instead, the output has no line breaks
An implementation of PseudoPrimeGenerator
which uses a prime table generated by trial division.
Represents an XML
Instruction
; IE, <? … ?> TODO: Add parent arg (3rd arg) to constructor
A RingServer
allows a Rinda::TupleSpace
to be located via UDP broadcasts. Default service location uses the following steps:
A RingServer
begins listening on the network broadcast UDP address.
A RingFinger
sends a UDP packet containing the DRb
URI
where it will listen for a reply.
The RingServer
receives the UDP packet and connects back to the provided DRb
URI
with the DRb
service.
A RingServer
requires a TupleSpace:
ts = Rinda::TupleSpace.new rs = Rinda::RingServer.new
RingServer
can also listen on multicast addresses for announcements. This allows multiple RingServers to run on the same host. To use network broadcast and multicast:
ts = Rinda::TupleSpace.new rs = Rinda::RingServer.new ts, %w[Socket::INADDR_ANY, 239.0.0.1 ff02::1]
RingProvider
uses a RingServer
advertised TupleSpace
as a name service. TupleSpace
clients can register themselves with the remote TupleSpace
and look up other provided services via the remote TupleSpace
.
Services are registered with a tuple of the format [:name, klass, DRbObject
, description].
A test case for Gem::Installer
.
AbstractSyntaxTree
provides methods to parse Ruby code into abstract syntax trees. The nodes in the tree are instances of RubyVM::AbstractSyntaxTree::Node
.
OpenSSL
IO
buffering mix-in module.
This module allows an OpenSSL::SSL::SSLSocket
to behave like an IO
.
You typically won’t use this module directly, you can see it implemented in OpenSSL::SSL::SSLSocket
.
A template for stream parser listeners. Note that the declarations (attlistdecl, elementdecl, etc) are trivially processed; REXML
doesn’t yet handle doctype entity declarations, so you have to parse them out yourself.
C struct shell
A C struct wrapper