The service responds with a series of {@value BITE_COUNT} dummy bites. Query
* parameters for this service are:
*
*
*
* | Key |
* Value |
* Default |
*
* | callback |
*
* The name of the callback function for a JSONP response, or leave it
* unspecified for a plain JSON response. This is a qualifier for the 'form'
* parameter whenever that parameter is set to 'json'. |
*
* Null, specifying a plain JSON response. |
*
*
* | form |
*
* The form of the response. Currently only 'json' is supported, which gives
* either JSON or JSONP depending on the value of the 'callback' parameter. |
*
* None, a value is required. |
*
*
* | pretty |
*
* Specify 'pretty' or 'pretty=y' for a more human-readable response. This
* adds whitespace and forces a content type of 'text/plain'. |
*
* 'n' |
*
*
*
*/
public final @ThreadSafe class DummyFeedSS extends HttpServlet // FIX by using WAP, per a/web/context/WEB-INF/web.xml
{
public @Override void init() throws ServletException
{
try
{
vsRun = new VoteServer( VOWicket.contextPathToVoteServerName( // OPT for space: if whole vote-server really needed, servlets ought to share it
getServletContext().getContextPath() )).new Run( /*isSingleThreaded*/false );
vsRun.init_done(); // nothing to do here anymore
}
catch( RuntimeException x ) { throw x; }
catch( Exception x ) { throw new ServletException( x ); }
}
// ------------------------------------------------------------------------------------
/** The number of dummy bites in each response.
*/
static final int BITE_COUNT = 10;
// 100 was causing client timeout on obsidian, as polls take too long to construct.
// - H t t p - S e r v l e t ----------------------------------------------------------
protected void doGet( final HttpServletRequest request, final HttpServletResponse response )
throws IOException
{
// This method is also called by the default implementation of doHead(), which
// discards the response body after learning its length.
try
{
logger.fine( HTTPServletRequestX.buildRequestSummary(request).toString() );
final boolean isPretty = HTTPServletRequestX.getBooleanParameter( "pretty", request );
final String callback;
{
final String form = HTTPServletRequestX.getParameterRequired( "form", request );
if( !"json".equals( form ))
{
throw new HTTPRequestException( /*400*/HttpServletResponse.SC_BAD_REQUEST,
"unrecognized 'form' value: " + form );
}
callback = HTTPServletRequestX.getParameterNonEmpty( "callback", request );
}
// Commit to response.
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
final String characterEncoding = "UTF-8";
response.setCharacterEncoding( characterEncoding );
final Writer outBuf = new BufferedWriter( new OutputStreamWriter(
response.getOutputStream(), characterEncoding ));
if( callback != null )
{
outBuf.append( callback );
outBuf.append( '(' );
}
// note that response.isCommitted() when outBuf flushes
try
{
final JsonWriter outJSON = new JsonWriter( outBuf );
final String contentType;
if( isPretty )
{
contentType = "text/plain";
outJSON.setIndent( " " ); // otherwise it would be packed
}
else contentType = callback == null? "application/json": "application/javascript";
response.setContentType( contentType );
final Random random = new Random();
final BiteJig bite = new BiteJig();
final Biter[] biters = Biter.U.assembleBiters( vsRun );
int iUsernameRandom = -1;
outJSON.beginArray();
for( int b = 0; b < BITE_COUNT; ++b )
{
// Configure bite properties known to this feed
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
for( int p = 0; p < 2; ++p )
{
for( ;; )
{
int i = random.nextInt( Dummy.USERNAME_ARRAY.length );
if( i == iUsernameRandom ) continue; // avoid duplicates
iUsernameRandom = i;
break;
}
bite.addPerson().setUser( IDPair.fromUsername(
Dummy.USERNAME_ARRAY[iUsernameRandom] ));
}
final PollJig poll = bite.setPoll();
poll.setName( Dummy.POLL_NAME_ARRAY[random.nextInt(
Dummy.POLL_NAME_ARRAY.length )]);
poll.setIssueType( "Issue" ); // fake it, not actually used by client
// Maybe configure other properties, too
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
for( Biter biter: biters ) biter.configure( bite );
// Write configuration on wire
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bite.serialize( outJSON ); // clears bite, ready for re-configuration
}
outJSON.endArray();
if( callback != null )
{
outJSON.flush();
outBuf.append( ");" );
}
outJSON.close(); // throws exception if JSON imperfect, so don't close in finally block where it may mask a previous exception
}
finally { outBuf.close(); } // if not already closed
}
catch( Exception x )
{
if( !response.isCommitted() )
{
response.sendError( /*500*/HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
x.toString() );
}
logger.log( LoggerX.WARNING, "Error in service of request (" + request.getQueryString() + ")", x );
}
}
//// P r i v a t e ///////////////////////////////////////////////////////////////////////
private static final Logger logger = LoggerX.i( DummyFeedSS.class );
private volatile VoteServer.Run vsRun; // final after init
}