129 lines
3.6 KiB
C++
129 lines
3.6 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2004, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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//paragraph [1] Title: [{\Large \bf \begin {center}] [\end {center}}]
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//[TOC] [\tableofcontents]
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[1] Header File of the class ~PregelAlgebra~
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November 2018, J. Mende
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[TOC]
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1 Overview
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This file contains definitions of the members of class MessageFeed
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*/
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#include <ListUtils.h>
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#include <../../../Relation-C++/RelationAlgebra.h>
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#include <Stream.h>
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#include "MessageFeed.h"
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#include "../../MessageBroker/MessageBroker.h"
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#include "../../PregelContext.h"
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namespace pregel {
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ListExpr MessageFeed::typeMapping(ListExpr args) {
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if (!nl->HasLength(args, 0)) {
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return listutils::typeError("You must provide no arguments.");
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}
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std::string savedType = PregelContext::get().getMessageType();
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ListExpr tupleType;
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if (!nl->ReadFromString(savedType, tupleType)) {
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return listutils::typeError("Can't parse saved tuple type \"" +
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savedType + "\". Was it set?");
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}
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return nl->TwoElemList(nl->SymbolAtom(Symbol::STREAM()),
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tupleType);
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}
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int
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MessageFeed::valueMapping(Word *, Word &result, int streamOp, Word &local,
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Supplier) {
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supplier2<MessageWrapper> *messageSupplier;
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switch (streamOp) {
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case OPEN : {
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MessageBroker &broker = MessageBroker::get();
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const int lastRound = SuperstepCounter::get() - 1;
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messageSupplier = broker.inboxSupplier(lastRound);
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local.addr = messageSupplier;
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return 0;
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}
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case REQUEST : {
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messageSupplier = (supplier2<MessageWrapper> *) local.addr;
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std::shared_ptr<MessageWrapper> message = (*messageSupplier)();
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if (message != nullptr) {
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result.setAddr(message->getBody1());
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//delete message;
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return YIELD;
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} else {
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return CANCEL;
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}
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}
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case CLOSE :
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if (local.addr) {
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messageSupplier = (supplier2<MessageWrapper> *) local.addr;
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delete messageSupplier;
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local.addr = nullptr;
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}
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return 0;
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default:
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BOOST_LOG_TRIVIAL(warning) << "DEFAULT case. Abort.";
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break;
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}
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return 0;
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}
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OperatorSpec MessageFeed::operatorSpec(
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"() -> bool",
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"#",
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"This operator consumes the message buffer of the message broker that is a "
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"component of the Pregel system."
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"Each message is a tuple and is provided as a stream as the result "
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"of the operator.",
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"query messageFeed() consume;",
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"This operator belongs to the Pregel API."
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"It may require knowledge of the system to effectively understand and use "
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"all the operators that are provided."
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"CAUTION: This operator is used internally by the Pregel system. "
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"Hence you must not use it in queries yourself."
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"Doing so may lead to inconsistent states of the Pregel system."
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);
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Operator MessageFeed::messageFeed(
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"messageFeed",
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MessageFeed::operatorSpec.getStr(),
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MessageFeed::valueMapping,
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Operator::SimpleSelect,
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MessageFeed::typeMapping
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);
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}
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