1 // Copyright (C) 2000 - 2006 Philip Aston
2 // All rights reserved.
3 //
4 // This file is part of The Grinder software distribution. Refer to
5 // the file LICENSE which is part of The Grinder distribution for
6 // licensing details. The Grinder distribution is available on the
7 // Internet at http://grinder.sourceforge.net/
8 //
9 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
10 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
11 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
12 // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
13 // COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
14 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
15 // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
16 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
17 // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
18 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
19 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
20 // OF THE POSSIBILITY OF SUCH DAMAGE.
21
22 package net.grinder.statistics;
23
24
25 /**
26 * Interface to apply a statistics calculation to a {@link
27 * StatisticsSet}.
28 *
29 * @author Philip Aston
30 * @see StatisticExpressionFactoryImplementation
31 **/
32 public interface StatisticExpression {
33
34 /**
35 * Apply this {@link StatisticExpression} to the given {@link
36 * StatisticsSet} and return the result as a <code>double</code>.
37 *
38 * @param statisticsSet A <code>StatisticsSet</code> value.
39 * @return The result.
40 **/
41 double getDoubleValue(StatisticsSet statisticsSet);
42
43 /**
44 * Apply this {@link StatisticExpression} to the given {@link
45 * StatisticsSet} and return the result as a <code>long</code>,
46 * rounding as necessary.
47 *
48 * @param statisticsSet A <code>StatisticsSet</code> value.
49 * @return The result.
50 **/
51 long getLongValue(StatisticsSet statisticsSet);
52
53 /**
54 * Returns <code>true</code> if the type of this {@link
55 * StatisticExpression} is non integral. Callers might use this to
56 * decide which accessor to call to ensure that information is not
57 * lost, or how to format the result.
58 *
59 * @return a <code>boolean</code> value
60 **/
61 boolean isDouble();
62 }