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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_icl.examples.party"></a><a class="link" href="party.html" title="Party">Party</a> |
| </h3></div></div></div> |
| <p> |
| Example <span class="bold"><strong>party</strong></span> demonstrates the possibilities |
| of an interval map (<code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> |
| or <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_map.html" title="Class template split_interval_map">split_interval_map</a></code>). |
| An <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> maps |
| intervals to a given content. In this case the content is a set of party |
| guests represented by their name strings. |
| </p> |
| <p> |
| 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 <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> |
| 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 is done via an operator += that has to be implemented for the |
| content parameter of the <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code>. |
| Finally the interval_map contains the history of attendance and all points |
| in time, where the group of party guests changed. |
| </p> |
| <p> |
| Party demonstrates a principle that we call <span class="emphasis"><em><span class="bold"><strong>aggregate |
| on overlap</strong></span></em></span>: On insertion a value associated to the |
| interval is aggregated with those values in the interval_map that overlap |
| with the inserted value. There are two behavioral aspects to <span class="emphasis"><em><span class="bold"><strong>aggregate on overlap</strong></span></em></span>: a <span class="emphasis"><em><span class="bold"><strong>decompositional behavior</strong></span></em></span> and an <span class="emphasis"><em><span class="bold"><strong>accumulative behavior</strong></span></em></span>. |
| </p> |
| <div class="itemizedlist"><ul type="disc"> |
| <li> |
| The <span class="emphasis"><em><span class="bold"><strong>decompositional behavior</strong></span></em></span> |
| splits up intervals on the <span class="emphasis"><em>time</em></span><span class="emphasis"><em>dimension</em></span> |
| of the interval_map so that the intervals are split whenever associated |
| values change. |
| </li> |
| <li> |
| The <span class="emphasis"><em><span class="bold"><strong>accumulative behavior</strong></span></em></span> |
| accumulates associated values on every overlap of an insertion for the |
| associated values. |
| </li> |
| </ul></div> |
| <p> |
| The aggregation function is += by default. Different aggregations can be |
| used, if desired. |
| </p> |
| <p> |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="comment">// The next line includes <boost/date_time/posix_time/posix_time.hpp> |
| </span><span class="comment">// and a few lines of adapter code. |
| </span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">icl</span><span class="special">/</span><span class="identifier">ptime</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">icl</span><span class="special">/</span><span class="identifier">interval_map</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">std</span><span class="special">;</span> |
| <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">;</span> |
| <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">icl</span><span class="special">;</span> |
| |
| <span class="comment">// Type set<string> collects the names of party guests. Since std::set is |
| </span><span class="comment">// a model of the itl's set concept, the concept provides an operator += |
| </span><span class="comment">// that performs a set union on overlap of intervals. |
| </span><span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special"><</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">GuestSetT</span><span class="special">;</span> |
| |
| <span class="keyword">void</span> <span class="identifier">boost_party</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">GuestSetT</span> <span class="identifier">mary_harry</span><span class="special">;</span> |
| <span class="identifier">mary_harry</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Mary"</span><span class="special">);</span> |
| <span class="identifier">mary_harry</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Harry"</span><span class="special">);</span> |
| |
| <span class="identifier">GuestSetT</span> <span class="identifier">diana_susan</span><span class="special">;</span> |
| <span class="identifier">diana_susan</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Diana"</span><span class="special">);</span> |
| <span class="identifier">diana_susan</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Susan"</span><span class="special">);</span> |
| |
| <span class="identifier">GuestSetT</span> <span class="identifier">peter</span><span class="special">;</span> |
| <span class="identifier">peter</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Peter"</span><span class="special">);</span> |
| |
| <span class="comment">// A party is an interval map that maps time intervals to sets of guests |
| </span> <span class="identifier">interval_map</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">,</span> <span class="identifier">GuestSetT</span><span class="special">></span> <span class="identifier">party</span><span class="special">;</span> |
| |
| <span class="identifier">party</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span> <span class="comment">// add and element |
| </span> <span class="identifier">make_pair</span><span class="special">(</span> |
| <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 19:30"</span><span class="special">),</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 23:00"</span><span class="special">)),</span> |
| <span class="identifier">mary_harry</span><span class="special">));</span> |
| |
| <span class="identifier">party</span> <span class="special">+=</span> <span class="comment">// element addition can also be done via operator += |
| </span> <span class="identifier">make_pair</span><span class="special">(</span> |
| <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 20:10"</span><span class="special">),</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-21 00:00"</span><span class="special">)),</span> |
| <span class="identifier">diana_susan</span><span class="special">);</span> |
| |
| <span class="identifier">party</span> <span class="special">+=</span> |
| <span class="identifier">make_pair</span><span class="special">(</span> |
| <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 22:15"</span><span class="special">),</span> |
| <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-21 00:30"</span><span class="special">)),</span> |
| <span class="identifier">peter</span><span class="special">);</span> |
| |
| |
| <span class="identifier">interval_map</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">,</span> <span class="identifier">GuestSetT</span><span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">party</span><span class="special">.</span><span class="identifier">begin</span><span class="special">();</span> |
| <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"----- History of party guests -------------------------\n"</span><span class="special">;</span> |
| <span class="keyword">while</span><span class="special">(</span><span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">party</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> |
| <span class="special">{</span> |
| <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">when</span> <span class="special">=</span> <span class="identifier">it</span><span class="special">-></span><span class="identifier">first</span><span class="special">;</span> |
| <span class="comment">// Who is at the party within the time interval 'when' ? |
| </span> <span class="identifier">GuestSetT</span> <span class="identifier">who</span> <span class="special">=</span> <span class="special">(*</span><span class="identifier">it</span><span class="special">++).</span><span class="identifier">second</span><span class="special">;</span> |
| <span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">when</span> <span class="special"><<</span> <span class="string">": "</span> <span class="special"><<</span> <span class="identifier">who</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="special">}</span> |
| |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">">>Interval Container Library: Sample boost_party.cpp <<\n"</span><span class="special">;</span> |
| <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"-------------------------------------------------------\n"</span><span class="special">;</span> |
| <span class="identifier">boost_party</span><span class="special">();</span> |
| <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="comment">// Program output: |
| </span><span class="comment">/*----------------------------------------------------------------------------- |
| >>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 |
| -----------------------------------------------------------------------------*/</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| </p> |
| <div class="caution"><table border="0" summary="Caution"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../../doc/src/images/caution.png"></td> |
| <th align="left">Caution</th> |
| </tr> |
| <tr><td align="left" valign="top"> |
| <p> |
| </p> |
| <p> |
| We are introducing <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> |
| using an <span class="emphasis"><em>interval map <span class="emphasis"><em><span class="bold"><strong>of sets |
| of strings</strong></span></em></span></em></span>, because of it's didactic advantages. |
| The party example is used to give an immediate access to the basic ideas |
| of interval maps and <span class="emphasis"><em>aggregate on overlap</em></span>. For real |
| world applications, an interval_map of sets is not necessarily recommended. |
| It has the same efficiency problems as a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code> |
| of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sets</span></code>. There is a big realm though of |
| using interval_maps with numerical and other efficient data types for the |
| associated values. |
| </p> |
| </td></tr> |
| </table></div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2007 -2010 Joachim Faulhaber<br>Copyright © 1999 -2006 Cortex Software GmbH<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
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