Line data Source code
1 :
2 : /* Copyright (c) 2011-2014, Stefan Eilemann <eile@eyescale.ch>
3 : * 2011, Carsten Rohn <carsten.rohn@rtt.ag>
4 : * 2011-2012, Daniel Nachbaur <danielnachbaur@gmail.com>
5 : *
6 : * This file is part of Collage <https://github.com/Eyescale/Collage>
7 : *
8 : * This library is free software; you can redistribute it and/or modify it under
9 : * the terms of the GNU Lesser General Public License version 2.1 as published
10 : * by the Free Software Foundation.
11 : *
12 : * This library is distributed in the hope that it will be useful, but WITHOUT
13 : * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 : * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
15 : * details.
16 : *
17 : * You should have received a copy of the GNU Lesser General Public License
18 : * along with this library; if not, write to the Free Software Foundation, Inc.,
19 : * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 : */
21 :
22 : #ifndef CO_QUEUESLAVE_H
23 : #define CO_QUEUESLAVE_H
24 :
25 : #include <co/api.h>
26 : #include <co/object.h> // base class
27 : #include <co/types.h>
28 :
29 : namespace co
30 : {
31 : namespace detail { class QueueSlave; }
32 :
33 : /**
34 : * The consumer end of a distributed queue.
35 : *
36 : * One or more instances of this class are mapped to the identifier of the
37 : * QueueMaster registered on another node.
38 : */
39 : class QueueSlave : public Object
40 : {
41 : public:
42 : /**
43 : * Construct a new queue consumer.
44 : *
45 : * The implementation will prefetch items from the queue master to cache
46 : * them locally. The prefetchMark determines when new items are requested,
47 : * and the prefetchAmount how many items are fetched. Prefetching items
48 : * hides the network latency by pipelining the network communication with
49 : * the processing, but introduces some imbalance between queue slaves.
50 : *
51 : * @param prefetchMark the low-water mark for prefetching, or
52 : * LB_UNDEFINED_UINT32 to use the Global default.
53 : * @param prefetchAmount the refill quantity when prefetching, or
54 : * LB_UNDEFINED_UINT32 to use the Global default.
55 : * @version 1.0
56 : */
57 : CO_API QueueSlave( const uint32_t prefetchMark = LB_UNDEFINED_UINT32,
58 : const uint32_t prefetchAmount = LB_UNDEFINED_UINT32 );
59 :
60 : /** Destruct this queue consumer. @version 1.0 */
61 : virtual CO_API ~QueueSlave();
62 :
63 : /**
64 : * Dequeue an item.
65 : *
66 : * The returned item can deserialize additional data using the DataIStream
67 : * operators.
68 : *
69 : * @param timeout An optional timeout for the operation.
70 : * @return an item from the distributed queue, or an invalid item if the
71 : * queue is empty or the operation timed out.
72 : * @version 1.0
73 : */
74 : CO_API ObjectICommand pop( const uint32_t timeout = LB_TIMEOUT_INDEFINITE );
75 :
76 : protected:
77 0 : ChangeType getChangeType() const override { return STATIC; }
78 0 : void getInstanceData( co::DataOStream& ) override { LBDONTCALL }
79 : void applyInstanceData( co::DataIStream& is ) override;
80 :
81 : private:
82 : detail::QueueSlave* const _impl;
83 :
84 : CO_API void attach( const uint128_t& id,
85 : const uint32_t instanceID ) override;
86 : };
87 :
88 : } // co
89 :
90 : #endif // CO_QUEUESLAVE_H
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