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diff --git a/TAO/docs/releasenotes/OBV.html b/TAO/docs/releasenotes/OBV.html index c880e37823a..2878175f439 100644 --- a/TAO/docs/releasenotes/OBV.html +++ b/TAO/docs/releasenotes/OBV.html @@ -12,48 +12,47 @@ <h1><a name="orb"></a>Objects-by-Value</h1> Points of contact: <a href="mailto: parsons@cs.wustl.edu">Jeff Parsons</a> <a href="mailto: bosk@ipmce.ru">Boris Kolpackov</a> + <a href="mailto:g.edwards@vanderbilt.edu">George Edwards</a> - <p>Last Update: 2002/07/29 </p> + <p>Last Update: 2003/06/30 </p> </center> - <p>Objects-by-Value (OBV) describes the new type, <CODE>valuetype</CODE>. - It is introduced in CORBA 2.3 + <p>Objects-by-Value (OBV) describes the new type, <CODE>valuetype</CODE>, introduced in CORBA 2.3 <br>(Core: - <a href="ftp://ftp.omg.org/pub/docs/ptc/98-12-04.pdf">ptc/98-12-04.pdf - </a> Mapping to C++: - <a href="ftp://ftp.omg.org/pub/docs/ptc/98-09-03.pdf">ptc/98-09-03.pdf</a>). - This first implementation was contributed from - <a href="mailto: kuepper2@uni-wuppertal.de">Torsten Kuepper</a>. - <CODDE>Valuetype</CODE>s are similar to IDL <CODE>struct</CODE>s extended with - these features: + <a href="http://www.omg.org/cgi-bin/apps/doc?formal/02-12-06.pdf">formal/02-12-06.pdf</a>; Mapping to C++: + <a href="http://www.omg.org/cgi-bin/apps/doc?formal/03-06-03.pdf">formal/03-06-03.pdf</a>). + <p>The original TAO implementation was contributed by + <a href="mailto: kuepper2@uni-wuppertal.de">Torsten Kuepper</a>, and has subsequently been enhanced and corrected by <a href="mailto: parsons@cs.wustl.edu">Jeff Parsons</a> and <a href="mailto:g.edwards@vanderbilt.edu">George Edwards</a>. + <p><CODE>Valuetype</CODE>s are similar to IDL <CODE>struct</CODE>s extended with + these capabilities: <ul> - <li><p>Encapsulate state and operations with local implementation.</p> + <li><p>Encapsulate both state information and operations in an implementation that is guaranteed to be local.</p> </li> - <li><p>Single inheritance from a <CODE>valuetype</CODE> and - multiple inheritance from abstract - <CODE>valuetype</CODE>s. Eventually support of an - interface.</p> + <li><p>Can be declared <CODE>abstract</CODE>, in which case no state members are defined.</p> </li> - <li><p>References to other <CODE>valuetype</CODE>s, with the +<li><p>Can inherit from a single concrete <CODE>valuetype</CODE> and multiple <CODE>abstract valuetype</CODE>s.</p></li> +<li><p>Can support a single concrete <CODE>interface</CODE>, allowing them to be manipulated as either a valuetype or an object reference.</p></li> +<li><p>Can support multiple <CODE>abstract interface</CODE>s, allowing them to be substituted for those interfaces in operation invocations.</p></li> + <li><p>Can hold references to other <CODE>valuetype</CODE>s, with the possibility of NULL references or shared (aliased) references.</p> </li> </ul> - <p><CODE>Valuetype</CODE>s will likely be used to implement - abstract datatypes (ADT)s that can be copied to another process. - All processes that use the <CODE>valuetype</CODE> must have an - implementation for it since CORBA does not support code - migration, a la Java RMI.</p> - +<p>Valuetypes have the following uses: +<UL> +<li><p>Implement abstract datatypes (ADTs) that can be copied to another process.</p></li> +<li><p>Represent <CODE>eventtype</CODE>s in the Event Service.</p></li> +<li><p>Ensure operations are executed locally for increased performance.</p></li> +</UL> <a name="current"><h3>Current status:</h3></a> <ul> <li><p>The IDL compiler understands <CODE>valuetype</CODE>. Relevant options of TAO's IDL compiler are: <P> <UL> - <LI>-Gv Enable OBV support - <LI>-Sv Disable OBV support (default) + <LI>-Gv Enable OBV support (default) + <LI>-Sv Disable OBV support <LI>-Wb,obv_opt_accessor Make accessor and modifier functions inline. Overriding them is not allowed in this mode. </UL> @@ -62,31 +61,36 @@ <li><p><CODE>Valuetype</CODE>s can be used as arguments in CORBA invocations. There is an example in <A HREF="../../examples/OBV/Typed_Events">$TAO_ROOT/TAO/examples/OBV/Typed_Events</A>. - <CODE>Valuetype</CODE>s could even reference other + <CODE>Valuetype</CODE>s can reference other <CODE>valuetype</CODE> objects (but without sharing). </p> </li> <li> - <p> Support for valuetypes as members of IDL aggregate types has been + <p>Support for valuetypes as members of IDL aggregate types has been added.</p> </li> <li> - <p> Support for inheritance from interface (supports) has been added. </p> - </li> - <li> - <p> Support for abstract interfaces has been added.</p> + <p>Support for inheritance from a concrete interface (<CODE>supports</CODE>) has been added. There is an example in <A HREF="../../tests/OBV/Supports">$TAO_ROOT/TAO/tests/OBV/Supports</A>.</p> </li> +<li> +<p>Support for inheritance from abstract interfaces has been added. There is an example in <A HREF="../../tests/Abstract_Interface">$TAO_ROOT/TAO/tests/Abstract_Interface</A>.</p> <li> - <p> Support for forward declared valuetypes defined in another compilation - unit has been added.</p> - </li> + <p>Support for forward declared valuetypes defined in another compilation + unit has been added. See <A HREF="../../examples/OBV/Typed_Events">$TAO_ROOT/TAO/examples/OBV/Typed_Events</A>.</p> + </li> +<li> +<p>Support for recursively-defined valuetypes has been added. See <A HREF="../../tests/OBV/Supports">$TAO_ROOT/TAO/tests/OBV/Supports</A>.</p> +</li> +<li> +<p>Support for user-declared factories has been added. See <A HREF="../../tests/OBV/Factory">$TAO_ROOT/TAO/tests/OBV/Factory</A>.</p> +</li> </ul> <a name="issues"><h3>Known issues:</h3></a> <ul> <li><p><CODE>Valuetype</CODE>s work only in conjunction with - compiled marshalling (<CODE>-Gc</CODE>, currently default for + compiled marshaling (<CODE>-Gc</CODE>, currently default for <CODE>tao_idl</CODE>). </p> </li> @@ -98,6 +102,9 @@ <li><p>No support for <CODE>valuebox</CODE>es </p> </li> +<li> +<p> +No support for <CODE>valuetype</CODE>s with cyclic references.</p></li> <li><p>No support for fragmentation (chunking) of the marshalled <CODE>valuetype</CODE> object. Hence no support for truncation or @@ -112,12 +119,6 @@ </p> </li> - <li><p>Obtaining a repository id of a <CODE>valuetype</CODE> - is currently non-standard. Hashed repository ids are not - implemented. - </p> - </li> - <li><p>The map of <CODE>valuetype</CODE> factories needs some revision to provide proper locking. Currently the registration of factories is best completed before |