xref: /aoo41x/main/udkapi/com/sun/star/io/XAsyncOutputMonitor.idl (revision cdf0e10c)

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#ifndef __com_sun_star_io_XAsyncOutputMonitor_idl__
#define __com_sun_star_io_XAsyncOutputMonitor_idl__

#ifndef __com_sun_star_io_IOException_idl__
#include "com/sun/star/io/IOException.idl"
#endif
#ifndef __com_sun_star_uno_XInterface_idl__
#include "com/sun/star/uno/XInterface.idl"
#endif

module com { module sun { module star { module io {

/**
   An optional companion interface to
   <type scope="com::sun::star::io">XOutputStream</type> that supports scenarios
   where <member scope="com::sun::star::io">XOutputStream::writeBytes</member>
   operates asynchronously and does not necessarily report any errors.

   <p>A typical scenario where this interface is useful is when an
   <type scope="com::sun::star::io">XOutputStream</type> is used to write to a
   file via NFS.  Normally, any calls to
   <member scope="com::sun::star::io">XOutputStream::writeBytes</member> will
   execute asynchronously then, in that any potential errors might only be
   reported by later calls to
   <member scope="com::sun::star::io">XOutputStream::writeBytes</member> or
   <member scope="com::sun::star::io">XOutputStream::closeOutput</member>.  If
   such an output stream shall not be closed immediately after one or more calls
   to <member scope="com::sun::star::io">XOutputStream::writeBytes</member>, but
   the client wants to know as soon as possible whether writing was successful,
   then <member
   scope="com::sun::star::io">XAsyncOutputMonitor::waitForCompletion</member>
   should be called after the series of calls to
   <member scope="com::sun::star::io">XOutputStream::writeBytes</member>.</p>

   @since OOo 2.0
*/
interface XAsyncOutputMonitor {
    /**
       waits for the completion of any previous calls to
       <member scope="com::sun::star::io">XOutputStream::writeBytes</member>,
       and reports potentially pending errors.

       <p>Calling this method is potentially expensive (even if the associated
       <type scope="com::sun::star::io">XOutputStream</type> represents a local
       file not accessed via NFS, for example).  This method has a similar
       description to
       <member scope="com::sun::star::io">XOutputStream::flush</member>.
       However, where the semantics of <code>flush</code> are rather vague,
       <code>waitForCompletion</code> has very specific semantics&mdash;it just
       blocks long enough so that any errors encountered during previous calls
       to <member scope="com::sun::star::io">XOutputStream::writeBytes</member>
       can reliably be reported.  It specificially does not guarantee that any
       data have savely been stored on a stable physical medium, like a hard
       disk (and it is completely unspecified whether <code>flush</code> should
       give this guarantee).</p>

       @throws com::sun::star::io::IOException
       if any previous call to <member
       scope="com::sun::star::io">XOutputStream::writeBytes</member> encountered
       such an error, but has not yet reported it (in cases where
       <code>writeBytes</code> operates asynchronously).
    */
    void waitForCompletion() raises (IOException);
};

}; }; }; };

#endif