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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.druid.java.util.common;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import com.google.common.collect.PeekingIterator;
import org.apache.druid.java.util.common.guava.Comparators;
import org.joda.time.DateTime;
import org.joda.time.DateTimeComparator;
import org.joda.time.Interval;
import org.joda.time.chrono.ISOChronology;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.SortedSet;
import java.util.TreeSet;
/**
*
*/
public class JodaUtils
{
// limit intervals such that duration millis fits in a long
public static final long MAX_INSTANT = Long.MAX_VALUE / 2;
public static final long MIN_INSTANT = Long.MIN_VALUE / 2;
/**
* Condense the provided intervals such that the returned list has no abutting intervals, no overlapping intervals,
* and no zero-length intervals.
*
* This method is most efficient if the input intervals are in a {@link SortedSet} whose comparator is
* {@link Comparators#intervalsByStartThenEnd()}.
*
* @param intervals The Iterable object containing the intervals to condense
* @return The condensed intervals
*/
public static List condenseIntervals(Iterable intervals)
{
final SortedSet sortedIntervals;
if (intervals instanceof SortedSet
&& (Comparators.intervalsByStartThenEnd().equals(((SortedSet) intervals).comparator()))) {
sortedIntervals = (SortedSet) intervals;
} else {
sortedIntervals = new TreeSet<>(Comparators.intervalsByStartThenEnd());
for (Interval interval : intervals) {
sortedIntervals.add(interval);
}
}
return ImmutableList.copyOf(condensedIntervalsIterator(sortedIntervals.iterator()));
}
/**
* Condense the provided intervals such that the returned list has no abutting intervals, no overlapping intervals,
* and no zero-length intervals.
*
* The provided intervals must be sorted in ascending order using {@link Comparators#intervalsByStartThenEnd()}.
* Otherwise, results are undefined.
*
* The method avoids materialization by incrementally condensing the intervals by
* starting from the first and looking for "adjacent" intervals. This is
* possible since intervals in the Iterator are in ascending order (as
* guaranteed by the caller).
*
* @param sortedIntervals The iterator object containing the intervals to condense
*
* @return An iterator for the condensed intervals. By construction the condensed intervals are sorted
* in ascending order and contain no repeated elements. The iterator can contain nulls,
* they will be skipped if it does.
*
* @throws IAE if an element is null or if sortedIntervals is not sorted in ascending order
*/
public static Iterator condensedIntervalsIterator(Iterator sortedIntervals)
{
if (sortedIntervals == null || !sortedIntervals.hasNext()) {
return Collections.emptyIterator();
}
final PeekingIterator peekingIterator =
Iterators.peekingIterator(
Iterators.filter(
sortedIntervals,
interval -> interval == null || interval.toDurationMillis() > 0
)
);
return new Iterator()
{
private Interval previous;
@Override
public boolean hasNext()
{
return peekingIterator.hasNext();
}
@Override
public Interval next()
{
if (!hasNext()) {
throw new NoSuchElementException();
}
Interval currInterval = peekingIterator.next();
if (currInterval == null) {
throw new IAE("Element of intervals is null");
}
// check sorted ascending:
verifyAscendingSortOrder(previous, currInterval);
previous = currInterval;
while (hasNext()) {
Interval next = peekingIterator.peek();
if (next == null) {
throw new IAE("Element of intervals is null");
}
if (currInterval.abuts(next)) {
currInterval = new Interval(currInterval.getStart(), next.getEnd());
peekingIterator.next();
} else if (currInterval.overlaps(next)) {
DateTime nextEnd = next.getEnd();
DateTime currEnd = currInterval.getEnd();
currInterval = new Interval(
currInterval.getStart(),
nextEnd.isAfter(currEnd) ? nextEnd : currEnd
);
peekingIterator.next();
} else {
break;
}
}
return currInterval;
}
};
}
private static void verifyAscendingSortOrder(Interval previous, Interval current)
{
if (previous != null && previous.isAfter(current)) {
throw new IAE("Adjacent intervals are not sorted [%s,%s]", previous, current);
}
}
public static Interval umbrellaInterval(Iterable intervals)
{
boolean emptyIntervals = true;
DateTimeComparator dateTimeComp = DateTimeComparator.getInstance();
DateTime minStart = new DateTime(Long.MAX_VALUE, ISOChronology.getInstanceUTC());
DateTime maxEnd = new DateTime(Long.MIN_VALUE, ISOChronology.getInstanceUTC());
for (Interval interval : intervals) {
emptyIntervals = false;
minStart = Collections.min(ImmutableList.of(minStart, interval.getStart()), dateTimeComp);
maxEnd = Collections.max(ImmutableList.of(maxEnd, interval.getEnd()), dateTimeComp);
}
if (emptyIntervals) {
throw new IllegalArgumentException("Empty list of intervals");
}
return new Interval(minStart, maxEnd);
}
public static DateTime minDateTime(DateTime... times)
{
if (times == null) {
return null;
}
switch (times.length) {
case 0:
return null;
case 1:
return times[0];
default:
DateTime min = times[0];
for (int i = 1; i < times.length; ++i) {
min = min.isBefore(times[i]) ? min : times[i];
}
return min;
}
}
public static DateTime maxDateTime(DateTime... times)
{
if (times == null) {
return null;
}
switch (times.length) {
case 0:
return null;
case 1:
return times[0];
default:
DateTime max = times[0];
for (int i = 1; i < times.length; ++i) {
max = max.isAfter(times[i]) ? max : times[i];
}
return max;
}
}
}