...
The Slice compiler generates the following code for this definition:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
classdef TimeOfDay < Ice.Value
properties
hour int16
minute int16
second int16
tz char
end
methods
function obj = TimeOfDay(hour, minute, second, tz)
...
end
function id = ice_id(obj)
...
end
...
end
methods(Static)
function id = ice_staticId()
...
end
end
end |
...
Classes implicitly inherit from a common base class, Value, which is mapped to Ice.Value. Value is a very simple base class with just a few methods:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
classdef (Abstract) Value < matlab.mixin.Copyable
methods
function ice_preMarshal(obj)
end
function ice_postUnmarshal(obj)
end
function r = ice_getSlicedData(obj)
...
end
...
end
methods(Abstract)
id = ice_id(obj)
end
methods(Static)
function id = ice_staticId()
id = '::Ice::Object'
end
end
end |
...
Optional data members use the same mapping as required data members, but an optional data member can also be set to the marker value Ice.Unset to indicate that the member is unset. A well-behaved program must test an optional data member before using its value:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
obj = ...;
if obj.optionalMember ~= Ice.Unset
fprintf('optionalMember = %s\n', ex.optionalMember);
else
fprintf('optionalMember is unset\n');
end |
The Ice.Unset marker value has different semantics than an empty array. Since an empty array is a legal value for certain Slice types, the Ice run time requires a separate marker value so that it can determine whether an optional value is set. An optional value set to an empty array is considered to be set. If you need to distinguish between an unset value and a value set to an empty array, you can do so as follows:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
obj = ...;
if obj.optionalMember == Ice.Unset
fprintf('optionalMember is unset\n');
elseif isempty(obj.optionalMember)
fprintf('optionalMember is empty\n');
else
fprintf('optionalMember = %s\n', ex.optionalMember);
end |
...
The Slice compiler produces the following generated code for this definition:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
classdef TimeOfDay < Ice.Value
properties(Access=protected)
hour int16
minute int16
second int16
tz char
end
...
end |
...
If you wish, you can create your own custom derived class, and tell Ice to create and return these instances instead. For example:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
classdef CustomTimeOfDay < TimeOfDay
methods
function format(obj)
% prints formatted data members
end
end
end |
You then create and register a value factory for your custom class with your Ice communicator:
| Code Block |
|---|
| language | matlab |
|---|
| title | MATLAB |
|---|
|
function v = factory(type)
assert(strcmp(type, TimeOfDay.ice_staticId()));
v = CustomTimeOfDay();
end
communicator = ...;
communicator.getValueFactoryManager().add(@factory, TimeOfDay.ice_staticId()); |
...