ceph/src/boost/libs/graph/doc/EventVisitor.html

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   9 <Head>
  10 <Title>Boost Graph Library: EventVisitor</Title>
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  17
  18 <H1>EventVisitor Concept</H1>
  19
  20 This concept defines the interface for single-event visitors. An
  21 EventVisitor has an apply member function (<tt>operator()</tt>) which
  22 is invoked within the graph algorithm at the event-point specified by
  23 the <tt>event_filter</tt> typedef within the
  24 EventVisitor. EventVisitor's can be combined into an <a
  25 href="./EventVisitorList.html">EventVistorList</a>.
  26
  27 <p>
  28 The following is the list of event tags that can be invoked in BGL
  29 algorithms. Each tag corresponds to a member function of the visitor
  30 for an algorithm. For example, the <a
  31 href="./BFSVisitor.html">BFSVisitor</a> of <a
  32 href="./breadth_first_search.html"><tt>breadth_first_search()</tt></a>
  33 has a <tt>cycle_edge()</tt> member function. The corresponding tag is
  34 <tt>on_cycle_edge</tt>. The first argument is the event visitor's
  35 <tt>operator()</tt> must be either an edge or vertex descriptor
  36 depending on the event tag.
  37
  38 <pre>
  39 namespace boost {
  40   struct on_initialize_vertex { };
  41   struct on_start_vertex { };
  42   struct on_discover_vertex { };
  43   struct on_examine_edge { };
  44   struct on_tree_edge { };
  45   struct on_cycle_edge { };
  46   struct on_finish_vertex { };
  47   struct on_forward_or_cross_edge { };
  48   struct on_back_edge { };
  49   struct on_edge_relaxed { };
  50   struct on_edge_not_relaxed { };
  51   struct on_edge_minimized { };
  52   struct on_edge_not_minimized { };
  53 } // namespace boost
  54 </pre>
  55
  56
  57 <h3>Refinement of</h3>
  58
  59 <a href="../../utility/CopyConstructible.html">Copy Constructible</a>
  60 (copying a visitor should be a lightweight operation).
  61
  62 <h3>Notation</h3>
  63
  64 <Table>
  65 <TR>
  66 <TD><tt>G</tt></TD>
  67 <TD>A type that is a model of <a href="./Graph.html">Graph</a>.</TD>
  68 </TR>
  69
  70 <TR>
  71 <TD><tt>g</tt></TD>
  72 <TD>An object of type <tt>G</tt>.</TD>
  73 </TR>
  74
  75 <TR>
  76 <TD><tt>V</tt></TD>
  77 <TD>A type that is a model of EventVisitor.</TD>
  78 </TR>
  79
  80 <TR>
  81 <TD><tt>vis</tt></TD>
  82 <TD>An object of type <tt>V</tt>.</TD>
  83 </TR>
  84
  85 <TR>
  86 <TD><tt>x</tt></TD>
  87 <TD>An object of type
  88 <tt>boost::graph_traits&lt;G&gt;::vertex_descriptor</tt>
  89 or <tt>boost::graph_traits&lt;G&gt;::edge_descriptor</tt>.</TD>
  90 </TR>
  91
  92 </table>
  93
  94 <h3>Associated Types</h3>
  95
  96 <Table border>
  97
  98 <TR>
  99 <TD>Event Filter </TD>
 100 <TD><TT>V::event_filter</TT></TD>
 101 <TD>
 102 A tag struct to specify on which event the visitor should be invoked.
 103 </TD>
 104 </TR>
 105
 106 </table>
 107
 108 <h3>Valid Expressions</h3>
 109
 110 <Table border>
 111
 112 <tr>
 113 <th>Name</th><th>Expression</th><th>Return Type</th><th>Description</th>
 114 </tr>
 115
 116 <tr>
 117 <td>Apply Visitor</td>
 118 <td><TT>vis(x, g)</TT></TD>
 119 <TD><TT>void</TT></TD>
 120 <TD>
 121 Invokes the visitor operation on object <tt>x</tt>, which is
 122 either a vertex or edge descriptor of the graph.
 123 </TD>
 124 </TR>
 125
 126
 127 </table>
 128
 129
 130 <h3>Models</h3>
 131
 132 <ul>
 133  <li><a
 134  href="./predecessor_recorder.html"><tt>predecessor_recorder</tt></a>
 135  <li><a href="./distance_recorder.html"><tt>distance_recorder</tt></a>
 136  <li><a href="./time_stamper.html"><tt>time_stamper</tt></a>
 137  <li><a href="./property_writer.html"><tt>property_writer</tt></a>
 138  <li><a href="./null_visitor.html"><tt>null_visitor</tt></a>
 139 </ul>
 140
 141 <h3>See Also</h3>
 142
 143 <a href="./EventVisitorList.html">EventVisitorList</a>,
 144 <a href="./visitor_concepts.html">Visitor concepts</a>
 145
 146 <br>
 147 <HR>
 148 <TABLE>
 149 <TR valign=top>
 150 <TD nowrap>Copyright &copy; 2000-2001</TD><TD>
 151 <A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>,
 152 Indiana University (<A
 153 HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br>
 154 <A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Indiana University (<A HREF="mailto:llee@cs.indiana.edu">llee@cs.indiana.edu</A>)<br>
 155 <A HREF="http://www.osl.iu.edu/~lums">Andrew Lumsdaine</A>,
 156 Indiana University (<A
 157 HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>)
 158 </TD></TR></TABLE>
 159
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