1 package org.opentrafficsim.road.gtu.generator.headway;
2
3 import java.util.Optional;
4
5 import org.djunits.value.vdouble.scalar.Duration;
6 import org.djunits.value.vdouble.scalar.Frequency;
7
8 /**
9 * Interface for arrivals in an {@code ArrivalsHeadwayGenerator}. Arrivals are defined as a piece-wise linear frequency over
10 * time.
11 * <p>
12 * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
13 * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
14 * </p>
15 * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
16 * @author <a href="https://github.com/peter-knoppers">Peter Knoppers</a>
17 * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
18 */
19 public interface Arrivals
20 {
21
22 /**
23 * Returns the demand at given time, which may be the sum of child objects. The input {@code sliceStart} is used to resolve
24 * the value at a time slice boundary in case of a stepwise (discontinuous) demand pattern. If {@code sliceStart = true} and
25 * {@code time} is a slice boundary, the demand value for <i>after</i> the slice boundary should be returned. In that case,
26 * the caller is processing a time slice after {@code time}, hence it's the slice start. If {@code sliceStart = false} the
27 * demand value of before the slice boundary should be returned. For continuous demand patterns, {@code sliceStart} can be
28 * ignored.
29 * @param time simulation time
30 * @param sliceStart whether the time is at the start of an arbitrary time slice
31 * @return returns the total demand for branching nodes, or the demand at a leaf node, at the given time
32 */
33 Frequency getFrequency(Duration time, boolean sliceStart);
34
35 /**
36 * Returns the start time of the next time slice after the given time or {@code null} if no such slice exists. The next time
37 * slice starts as soon as the current slice ends, where each slice has it's own linear (or constant) demand. Thus, any
38 * change of slope in the demand pattern initiates a new slice. If {@code time} is equal to a time slice boundary, the next
39 * value should be returned.
40 * @param time time after which the first slice start time is requested
41 * @return start time of the next time slice after the given time, empty if no such slice exists
42 */
43 Optional<Duration> nextTimeSlice(Duration time);
44
45 }