libs/icl/example/boost_party_/boost_party.cpp

/*-----------------------------------------------------------------------------+
Interval Container Library
Author: Joachim Faulhaber
Copyright (c) 2007-2009: Joachim Faulhaber
Copyright (c) 1999-2006: Cortex Software GmbH, Kantstrasse 57, Berlin
+------------------------------------------------------------------------------+
   Distributed under the Boost Software License, Version 1.0.
      (See accompanying file LICENCE.txt or copy at
           http://www.boost.org/LICENSE_1_0.txt)
+-----------------------------------------------------------------------------*/

/** Example boost_party.cpp \file boost_party.cpp 
    \brief Generates an attendance history of a party by inserting into an interval_map. 
           Demonstrating <i>aggregate on overlap</i>.

    boost_party.cpp demonstrates the possibilities of an interval map 
    (interval_map or split_interval_map). Boost::posix_time::ptime is used as time
    parameter. An interval_map maps intervals to a given content. In this case the 
    content is a set of party guests represented by their name strings.

    As time goes by, groups of people join the party and leave later in the evening.
    So we add a time interval and a name set to the interval_map for the attendance
    of each group of people, that come together and leave together.

    On every overlap of intervals, the corresponding name sets are accumulated. At
    the points of overlap the intervals are split. The accumulation of content on
    overlap of intervals is done via an operator += that has to be implemented
    for the content parameter of the interval_map.

    Finally the interval_map contains the history of attendance and all points in
    time, where the group of party guests changed.

    boost_party.cpp demonstrates a principle that we call 
    <b><em>aggregate on overlap</em></b>:
    On insertion a value associated to the interval is aggregated (added) to those
    values in the interval_map that overlap with the inserted value.

    There are two behavioral aspects to <b>aggregate on overlap</b>: a <em>decompositional
    behavior</em> and a <em>accumulative behavior</em>.

    The <em>decompositional behavior</em> splits up intervals on the time dimension of the 
    interval_map so that the intervals change whenever associated values
    change.

    The <em>accumulative behavior</em> accumulates associated values on every overlap of
    an insertion for the associated values.

    \include boost_party_/boost_party.cpp
*/
//[example_boost_party
// The next line includes <boost/date_time/posix_time/posix_time.hpp>
// and a few lines of adapter code.
#include <boost/icl/ptime.hpp> 
#include <iostream>
#include <boost/icl/interval_map.hpp>

using namespace std;
using namespace boost::posix_time;
using namespace boost::icl;

// Type set<string> collects the names of party guests. Since std::set is
// a model of the itl's set concept, the concept provides an operator += 
// that performs a set union on overlap of intervals.
typedef std::set<string> GuestSetT;

void boost_party()
{
    GuestSetT mary_harry; 
    mary_harry.insert("Mary");
    mary_harry.insert("Harry");

    GuestSetT diana_susan; 
    diana_susan.insert("Diana");
    diana_susan.insert("Susan");

    GuestSetT peter; 
    peter.insert("Peter");

    // A party is an interval map that maps time intervals to sets of guests
    interval_map<ptime, GuestSetT> party;

    party.add( // add and element
      make_pair( 
        interval<ptime>::right_open(
          time_from_string("2008-05-20 19:30"), 
          time_from_string("2008-05-20 23:00")), 
        mary_harry));

    party += // element addition can also be done via operator +=
      make_pair( 
        interval<ptime>::right_open(
          time_from_string("2008-05-20 20:10"), 
          time_from_string("2008-05-21 00:00")), 
        diana_susan);

    party +=
      make_pair( 
        interval<ptime>::right_open(
          time_from_string("2008-05-20 22:15"), 
          time_from_string("2008-05-21 00:30")), 
        peter);


    interval_map<ptime, GuestSetT>::iterator it = party.begin();
    cout << "----- History of party guests -------------------------\n";
    while(it != party.end())
    {
        interval<ptime>::type when = it->first;
        // Who is at the party within the time interval 'when' ?
        GuestSetT who = (*it++).second;
        cout << when << ": " << who << endl;
    }

}


int main()
{
    cout << ">>Interval Container Library: Sample boost_party.cpp <<\n";
    cout << "-------------------------------------------------------\n";
    boost_party();
    return 0;
}

// Program output:
/*-----------------------------------------------------------------------------
>>Interval Container Library: Sample boost_party.cpp <<
-------------------------------------------------------
----- History of party guests -------------------------
[2008-May-20 19:30:00, 2008-May-20 20:10:00): Harry Mary
[2008-May-20 20:10:00, 2008-May-20 22:15:00): Diana Harry Mary Susan
[2008-May-20 22:15:00, 2008-May-20 23:00:00): Diana Harry Mary Peter Susan
[2008-May-20 23:00:00, 2008-May-21 00:00:00): Diana Peter Susan
[2008-May-21 00:00:00, 2008-May-21 00:30:00): Peter
-----------------------------------------------------------------------------*/
//]