If you're doing this in Java, use the java.util.concurrent package and its Executor and Future framework, instead of using Thread.start/join, synchronized etc. directly.
Get the book "Concurrent Programming in Java: Design Principles and Patterns" (ISBN 0-201-31009-0) written by the master himself (Doug Lea; see http://gee.cs.oswego.edu/dl/cpj/ ) - Godmar On Feb 18, 2008 2:19 PM, Durbin, Michael R <[EMAIL PROTECTED]> wrote: > This can be done in Java, but like everything in Java the solution is kind of > lengthy and perhaps requires several classes. > > I've attached a simple skeleton program that spawns threads to search but > then processes only those results returned in the first 10 seconds. The code > for performing the searches is obviously missing as is the consolidation > code, but the concurrency issue is addressed. In this example the search > threads aren't killed, but instead left running to finish naturally though > their results would be ignored if they weren't done in 10 seconds. It might > be better to kill them depending on the circumstances. > > -Mike > > -----Original Message----- > From: Code for Libraries [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lease > Morgan > Sent: Monday, February 18, 2008 1:43 PM > To: CODE4LIB@LISTSERV.ND.EDU > Subject: [CODE4LIB] many processes, one resultCode for Libraries [EMAIL > PROTECTED] > > How do I write a computer program that spawns many processes but > returns one result? > > I suppose the classic example of my query is the federated search. Get > user input. Send it to many remote indexes. Wait. Combine results. > Return. In this scenario when one of the remote indexes is slow things > grind to a halt. > > I have a more modern example. Suppose I want to take advantage of many > Web Services. One might be spell checker. Another might be a > thesaurus. Another might be an index. Another might be a user lookup > function. Given this environment, where each Web Service will return > different sets of streams, how do I query each of them simultaneously > and then aggregate the result? I don't want to so this sequentially. I > want to fork them all at once and wait for their return before a > specific time out. In Perl I can use the system command to fork a > process, but I must wait for it to return. There is another Perl > command allowing me to fork a process and keep going but I don't > remember what it is. Neither one of these solutions seem feasible. Is > the idea of threading in Java suppose to be able to address this > problem? > > -- > Eric Lease Morgan > University Libraries of Notre Dame > > (574) 631-8604 >
