opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/utils/MutableUnsignedLongSet.java

   1 /*
   2  * Copyright (c) 2021 PANTHEON.tech, s.r.o. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.datastore.utils;
   9
  10 import com.google.common.annotations.Beta;
  11 import com.google.common.collect.Collections2;
  12 import com.google.common.collect.ImmutableRangeSet;
  13 import com.google.common.primitives.UnsignedLong;
  14 import java.util.TreeSet;
  15 import org.eclipse.jdt.annotation.NonNull;
  16 import org.opendaylight.yangtools.concepts.Mutable;
  17
  18 @Beta
  19 public final class MutableUnsignedLongSet extends UnsignedLongSet implements Mutable {
  20     MutableUnsignedLongSet(final TreeSet<Entry> ranges) {
  21         super(ranges);
  22     }
  23
  24     public static @NonNull MutableUnsignedLongSet of() {
  25         return new MutableUnsignedLongSet(new TreeSet<>());
  26     }
  27
  28     @Override
  29     public ImmutableUnsignedLongSet immutableCopy() {
  30         return ImmutableUnsignedLongSet.copyOf(this);
  31     }
  32
  33     public void add(final long longBits) {
  34         final var ranges = trustedRanges();
  35         final var range = Entry.of(longBits);
  36
  37         // We need Iterator.remove() to perform efficient merge below
  38         final var headIt = ranges.headSet(range, true).descendingIterator();
  39         if (headIt.hasNext()) {
  40             final var head = headIt.next();
  41             if (head.contains(longBits)) {
  42                 return;
  43             }
  44
  45             // Merge into head entry if possible
  46             if (head.upperBits + 1 == longBits) {
  47                 head.upperBits = longBits;
  48
  49                 // Potentially merge head entry and tail entry
  50                 final var tail = ranges.higher(range);
  51                 if (tail != null) {
  52                     if (tail.lowerBits - 1 == longBits) {
  53                         // Expand tail, remove head
  54                         tail.lowerBits = head.lowerBits;
  55                         headIt.remove();
  56                     }
  57                 }
  58                 return;
  59             }
  60         }
  61
  62         final var tail = ranges.higher(range);
  63         if (tail != null) {
  64             // Merge into tail entry if possible
  65             if (tail.lowerBits - 1 == longBits) {
  66                 tail.lowerBits = longBits;
  67                 return;
  68             }
  69         }
  70
  71         // No luck, store a new entry
  72         ranges.add(range);
  73     }
  74
  75     public ImmutableRangeSet<UnsignedLong> toRangeSet() {
  76         return ImmutableRangeSet.copyOf(Collections2.transform(trustedRanges(), Entry::toUnsigned));
  77     }
  78 }