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classdef Global
%This class is for internal use only. It may be removed in the future.
%GLOBAL Functions for handling the global node and global core
% MATLAB uses a unique, global ROS node object for each running MATLAB
% session. Optionally, MATLAB can also launch a global core.
% The robotics.ros.internal.Global class exposes functions that allow the
% manipulation of these global entities.
%
% robotics.ros.internal.Global methods:
% core - Initialize or clear the global ROS core object
% node - Initialize or clear the global ROS node object
% Copyright 2014-2015 The MathWorks, Inc.
properties(Access = ?matlab.unittest.TestCase, Constant)
%DefaultCorePort - The default port to start the global core
DefaultCorePort = 11311
%DefaultNodeName - The default prefix for the global node name
DefaultNodeName = 'matlab_global_node_'
%DefaultNodeNameDigits - Number of digits that are suffixed to the global node name
DefaultNodeNameDigits = 5
%RandomSource - Source of pseudo-random numbers for node name
RandomSource = robotics.internal.Random
end
methods (Static)
function masterURI = core( op, port )
%CORE Initialize or clear the global core object
% The operation 'op' defines the behavior of this function.
%
% robotics.ros.internal.Global.core('clear') clears (deletes) the global
% core. It will be reinitialized on the next call to ROSINIT or
% robotics.ros.internal.Global.core('init')
%
% robotics.ros.internal.Global.core('init', PORT)
% initializes the global ROS core on PORT. This call will fail
% if there is another core already running on that port. If
% PORT is [], the default of 11311 will be used.
switch op
case 'clear'
robotics.ros.internal.Global.coreInstance('clear');
if nargout > 0
masterURI = [];
end
case 'init'
if isempty(port)
port = robotics.ros.internal.Global.DefaultCorePort;
end
core = robotics.ros.internal.Global.coreInstance('init', ...
port);
if nargout > 0
masterURI = core.MasterURI;
end
otherwise
error(message('robotics:ros:core:GlobalCoreInvalidOp', op));
end
end
function node( op, name, masterURI, nodeHost )
%NODE Initialize or clear the global node object
% The operation 'op' defines the behavior of this function.
%
% robotics.ros.internal.Global.node('clear') clears (deletes) the global
% node. It will be reinitialized on the next call to ROSINIT or
% robotics.ros.internal.Global.node('init')
%
% robotics.ros.internal.Global.node('init', 'NAME', 'MASTERURI', 'NODEHOST')
% initializes the global ROS node.
% NAME is a the node name (specify '' if
% the default should be used). MASTERURI denotes the Master
% URI that the global node should connect to (use '' if the
% default should be used). The NODEHOST setting is used by
% the node to advertise itself (use '' for default).
switch op
case 'clear'
robotics.ros.internal.Global.nodeInstance('clear');
case 'init'
% Always clear existing node
robotics.ros.internal.Global.nodeInstance('clear');
% Then re-initialize node
robotics.ros.internal.Global.nodeInstance('init', ...
name, masterURI, nodeHost);
otherwise
error(message('robotics:ros:node:GlobalNodeInvalidOp', op));
end
end
function [active, nodeHandle] = isNodeActive
%isNodeActive Check if global node is running or not.
try
nodeHandle = robotics.ros.internal.Global.getNodeHandle(false);
active = true;
catch
active = false;
nodeHandle = [];
end
end
function [active, coreHandle] = isCoreActive
%isCoreActive Check if global core is running or not.
try
coreHandle = robotics.ros.internal.Global.getCoreHandle(false);
active = true;
catch
active = false;
coreHandle = [];
end
end
function node = getNodeHandle(init)
%getNodeHandle Get instance of the global node
node = robotics.ros.internal.Global.nodeInstance;
if ~isempty(node)
return;
end
% The global node is not initialized
if init
% Initialize the node if requested by the caller
robotics.ros.internal.Global.node('init', '', '', '');
node = robotics.ros.internal.Global.nodeInstance;
else
% If user did not request a node start, throw an
% appropriate error message
error(message('robotics:ros:node:GlobalNodeNotRunning'));
end
end
function core = getCoreHandle(init)
%getCoreHandle Get instance of the global node
core = robotics.ros.internal.Global.coreInstance;
if ~isempty(core)
return;
end
% The global core is not initialized
if init
% Initialize the core if requested by the caller
robotics.ros.internal.Global.core('init', []);
core = robotics.ros.internal.Global.coreInstance;
else
% If user did not request a core start, throw an
% appropriate error message
error(message('robotics:ros:core:GlobalCoreNotRunning'));
end
end
end
methods(Access = private, Static)
function n = nodeInstance(op, name, masterURI, nodeHost)
persistent node
mlock
if nargin == 0
n = node;
return;
end
switch op
case 'clear'
clearNode;
case 'init'
initNode(name, masterURI, nodeHost);
end
function initNode(name, masterURI, nodeHost)
if isempty(name)
name = robotics.ros.internal.Global.DefaultNodeName;
nodeCreateFcn = @(n,uri,nhost)robotics.ros.internal.Global.createNodeWithDefaultName(n, uri, 'NodeHost', nhost);
else
nodeCreateFcn = @(n,uri,nhost)robotics.ros.Node(n, uri, 'NodeHost', nhost);
end
clearNode;
node = nodeCreateFcn(name, masterURI, nodeHost);
disp(getString(message('robotics:ros:node:InitializeGlobal', ...
node.Name, node.NodeURI)));
end
function clearNode
% Check for the unlikely case that node is already a
% deleted handle and recover gracefully.
if isobject(node) && ~isvalid(node)
node = [];
return;
end
if ~isempty(node)
disp(getString(message('robotics:ros:node:ShuttingDownGlobal', ...
node.Name, node.NodeURI)));
delete(node);
node = [];
end
end
end
function c = coreInstance(op, port)
persistent core
mlock
if nargin == 0
c = core;
return;
end
switch op
case 'init'
initCore(port);
c = core;
case 'clear'
clearCore();
return;
end
function clearCore
% Check for the unlikely case that core is already a
% deleted handle and recover gracefully.
if isobject(core) && ~isvalid(core)
core = [];
return;
end
if ~isempty(core)
disp(getString(message('robotics:ros:core:ShuttingDownGlobal', ...
core.MasterURI)));
delete(core);
core = [];
end
end
function initCore(port)
if isempty(core)
core = robotics.ros.Core(port);
disp(getString(message('robotics:ros:core:InitializeGlobal', ...
core.MasterURI)));
return;
end
% If port number is different, restart core
if port ~= core.Port
clearCore();
core = robotics.ros.Core(port);
disp(getString(message('robotics:ros:core:InitializeGlobal', ...
core.MasterURI)));
end
end
end
function node = createNodeWithDefaultName(name, varargin)
%createNodeWithDefaultName Create the global ROS node with a default name
% The input arguments are fed straight into the robotics.ros.Node constructor.
nodeCreated = false;
% Create random node name
% Cycle multiple times in the (very unlikely) case that a node with
% the same name already exists.
retryMax = 3;
retryCount = 0;
numDigits = robotics.ros.internal.Global.DefaultNodeNameDigits;
while ~nodeCreated
% Use a random number as a suffix
randNumStr = robotics.ros.internal.Global.RandomSource.timeNumericString(numDigits);
try
node = robotics.ros.Node([name randNumStr], varargin{:});
catch ex
switch ex.identifier
case 'robotics:ros:node:NodeNameExists'
% This exception occurred because our
% random name collides with a name of a
% different node. Retry the node creation with
% a different random name up to retryMax times.
if retryCount == retryMax
error(message('robotics:ros:node:DefaultNodeNameError'));
end
retryCount = retryCount + 1;
% Pause for a little bit to ensure that time is
% changing. Randomize the wait time between 0.05 and 0.15
% seconds, in case that multiple instances of MATLAB
% use the same time base.
waitTime = 0.1 + 0.1*(rand-0.5);
pause(waitTime);
continue;
otherwise
% Some other exception occurred.
rethrow(ex);
end
end
nodeCreated = true;
end
end
end
end