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19ed6598 MK |
1 | /******************************************************************************* |
2 | * Copyright (c) 2016 Ericsson | |
3 | * | |
4 | * All rights reserved. This program and the accompanying materials are | |
5 | * made available under the terms of the Eclipse Public License v1.0 which | |
6 | * accompanies this distribution, and is available at | |
7 | * http://www.eclipse.org/legal/epl-v10.html | |
8 | *******************************************************************************/ | |
9 | ||
eeff806b | 10 | package org.eclipse.tracecompass.internal.analysis.os.linux.ui.views.resources; |
19ed6598 MK |
11 | |
12 | import java.util.Comparator; | |
13 | import java.util.Iterator; | |
14 | import java.util.NoSuchElementException; | |
15 | ||
16 | import org.eclipse.jdt.annotation.NonNull; | |
17 | import org.eclipse.tracecompass.tmf.ui.widgets.timegraph.model.ITimeEvent; | |
18 | ||
19 | /** | |
20 | * Caching iterator of time events with a couple extras. | |
21 | * <ul> | |
22 | * <li>peek() allows reading the head without removing it</li> | |
23 | * <li>trim() allows removing a bit of the first event</li> | |
24 | * </ul> | |
25 | * | |
26 | * @author Matthew Khouzam | |
27 | */ | |
28 | class CachingIterator implements Iterator<@NonNull ITimeEvent>, Comparable<CachingIterator> { | |
29 | private ITimeEvent fEvent; | |
30 | private @NonNull Iterator<@NonNull ? extends ITimeEvent> fIterator; | |
31 | private final Comparator<ITimeEvent> fComparator; | |
32 | ||
33 | public CachingIterator(@NonNull Iterator<@NonNull ? extends ITimeEvent> iterator, Comparator<ITimeEvent> comparator) { | |
34 | fIterator = iterator; | |
35 | fComparator = comparator; | |
36 | fEvent = iterator.hasNext() ? iterator.next() : null; | |
37 | } | |
38 | ||
39 | @Override | |
40 | public ITimeEvent next() { | |
41 | ITimeEvent retVal = fEvent; | |
42 | fEvent = fIterator.hasNext() ? fIterator.next() : null; | |
43 | if (retVal == null) { | |
44 | throw new NoSuchElementException("Iterator is empty"); //$NON-NLS-1$ | |
45 | } | |
46 | return retVal; | |
47 | } | |
48 | ||
49 | @Override | |
50 | public boolean hasNext() { | |
51 | return fEvent != null; | |
52 | } | |
53 | ||
54 | /** | |
55 | * Retrieves, but does not remove, the next element of this iterator, or | |
56 | * returns {@code null} if this iterator does not have a next. | |
57 | * | |
58 | * @return the next element of the iterator | |
59 | */ | |
60 | public ITimeEvent peek() { | |
61 | return fEvent; | |
62 | } | |
63 | ||
64 | @Override | |
65 | public int compareTo(CachingIterator o) { | |
66 | final ITimeEvent myEvent = peek(); | |
67 | final ITimeEvent otherEvent = o.peek(); | |
68 | return fComparator.compare(myEvent, otherEvent); | |
69 | } | |
70 | ||
71 | /** | |
72 | * Trims the next element in the iterator to be after a cut-off time. | |
73 | * | |
74 | * @param time | |
75 | * the cut-off time | |
76 | * @return true if there was a trim | |
77 | */ | |
78 | public boolean trim(long time) { | |
79 | if (time <= fEvent.getTime()) { | |
80 | return false; | |
81 | } | |
82 | if (time < fEvent.getTime() + fEvent.getDuration()) { | |
83 | fEvent = fEvent.splitAfter(time); | |
84 | return true; | |
85 | } | |
86 | fEvent = fIterator.hasNext() ? fIterator.next() : null; | |
87 | return true; | |
88 | } | |
89 | ||
90 | } |