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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 class="itemizedlist" style="list-style-type: disc; ">
- <li class="listitem">
- 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 class="listitem">
- 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>
- <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>
- <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>
- 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>
- </tr></table>
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