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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.utils.btree;
import java.util.*;
import com.google.common.collect.Ordering;
import org.apache.cassandra.utils.btree.BTree.Dir;
import static org.apache.cassandra.utils.btree.BTree.findIndex;
public class BTreeSet implements NavigableSet, List
{
protected final Comparator comparator;
protected final Object[] tree;
public BTreeSet(Object[] tree, Comparator comparator)
{
this.tree = tree;
this.comparator = comparator;
}
@Override
public Comparator comparator()
{
return comparator;
}
protected BTreeSearchIterator slice(Dir dir)
{
return BTree.slice(tree, comparator, dir);
}
public Object[] tree()
{
return tree;
}
/**
* The index of the item within the list, or its insertion point otherwise. i.e. binarySearch semantics
*/
public int indexOf(Object item)
{
return findIndex(tree, comparator, (V) item);
}
/**
* The converse of indexOf: provided an index between 0 and size, returns the i'th item, in set order.
*/
public V get(int index)
{
return BTree.findByIndex(tree, index);
}
public int lastIndexOf(Object o)
{
return indexOf(o);
}
public BTreeSet subList(int fromIndex, int toIndex)
{
return new BTreeRange(tree, comparator, fromIndex, toIndex - 1);
}
@Override
public int size()
{
return BTree.size(tree);
}
@Override
public boolean isEmpty()
{
return BTree.isEmpty(tree);
}
@Override
public BTreeSearchIterator iterator()
{
return slice(Dir.ASC);
}
@Override
public BTreeSearchIterator descendingIterator()
{
return slice(Dir.DESC);
}
@Override
public Object[] toArray()
{
return toArray(new Object[0]);
}
@Override
public T[] toArray(T[] a)
{
return toArray(a, 0);
}
public T[] toArray(T[] a, int offset)
{
int size = size();
if (a.length < size + offset)
a = Arrays.copyOf(a, size);
BTree.toArray(tree, a, offset);
return a;
}
public Spliterator spliterator()
{
return Spliterators.spliterator(this, Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.SIZED);
}
@Override
public BTreeSet subSet(V fromElement, boolean fromInclusive, V toElement, boolean toInclusive)
{
return new BTreeRange<>(tree, comparator, fromElement, fromInclusive, toElement, toInclusive);
}
@Override
public BTreeSet headSet(V toElement, boolean inclusive)
{
return new BTreeRange<>(tree, comparator, null, true, toElement, inclusive);
}
@Override
public BTreeSet tailSet(V fromElement, boolean inclusive)
{
return new BTreeRange<>(tree, comparator, fromElement, inclusive, null, true);
}
@Override
public SortedSet subSet(V fromElement, V toElement)
{
return subSet(fromElement, true, toElement, false);
}
@Override
public SortedSet headSet(V toElement)
{
return headSet(toElement, false);
}
@Override
public SortedSet tailSet(V fromElement)
{
return tailSet(fromElement, true);
}
@Override
public BTreeSet descendingSet()
{
return new BTreeRange(this.tree, this.comparator).descendingSet();
}
@Override
public V first()
{
return get(0);
}
@Override
public V last()
{
return get(size() - 1);
}
@Override
public V lower(V v)
{
return BTree.lower(tree, comparator, v);
}
@Override
public V floor(V v)
{
return BTree.floor(tree, comparator, v);
}
@Override
public V ceiling(V v)
{
return BTree.ceil(tree, comparator, v);
}
@Override
public V higher(V v)
{
return BTree.higher(tree, comparator, v);
}
@Override
public boolean contains(Object o)
{
return indexOf((V) o) >= 0;
}
@Override
public boolean containsAll(Collection c)
{
// TODO: if we ever use this method, it can be specialized quite easily for SortedSet arguments
for (Object o : c)
if (!contains(o))
return false;
return true;
}
public int hashCode()
{
// we can't just delegate to Arrays.deepHashCode(),
// because two equivalent sets may be represented by differently shaped trees
int result = 1;
for (V v : this)
result = 31 * result + Objects.hashCode(v);
return result;
}
@Override
public boolean addAll(Collection c)
{
throw new UnsupportedOperationException();
}
public boolean addAll(int index, Collection c)
{
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection c)
{
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection c)
{
throw new UnsupportedOperationException();
}
@Override
public void clear()
{
throw new UnsupportedOperationException();
}
@Override
public V pollFirst()
{
throw new UnsupportedOperationException();
}
@Override
public V pollLast()
{
throw new UnsupportedOperationException();
}
@Override
public boolean add(V v)
{
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o)
{
throw new UnsupportedOperationException();
}
public V set(int index, V element)
{
throw new UnsupportedOperationException();
}
public void add(int index, V element)
{
throw new UnsupportedOperationException();
}
public V remove(int index)
{
throw new UnsupportedOperationException();
}
public ListIterator listIterator()
{
throw new UnsupportedOperationException();
}
public ListIterator listIterator(int index)
{
throw new UnsupportedOperationException();
}
public static class BTreeRange extends BTreeSet
{
// both inclusive
protected final int lowerBound, upperBound;
BTreeRange(Object[] tree, Comparator comparator)
{
this(tree, comparator, null, true, null, true);
}
BTreeRange(BTreeRange from)
{
super(from.tree, from.comparator);
this.lowerBound = from.lowerBound;
this.upperBound = from.upperBound;
}
BTreeRange(Object[] tree, Comparator comparator, int lowerBound, int upperBound)
{
super(tree, comparator);
if (upperBound < lowerBound - 1)
upperBound = lowerBound - 1;
this.lowerBound = lowerBound;
this.upperBound = upperBound;
}
BTreeRange(Object[] tree, Comparator comparator, V lowerBound, boolean inclusiveLowerBound, V upperBound, boolean inclusiveUpperBound)
{
this(tree, comparator,
lowerBound == null ? 0 : inclusiveLowerBound ? BTree.ceilIndex(tree, comparator, lowerBound)
: BTree.higherIndex(tree, comparator, lowerBound),
upperBound == null ? BTree.size(tree) - 1 : inclusiveUpperBound ? BTree.floorIndex(tree, comparator, upperBound)
: BTree.lowerIndex(tree, comparator, upperBound));
}
// narrowing range constructor - makes this the intersection of the two ranges over the same tree b
BTreeRange(BTreeRange a, BTreeRange b)
{
this(a.tree, a.comparator, Math.max(a.lowerBound, b.lowerBound), Math.min(a.upperBound, b.upperBound));
assert a.tree == b.tree;
}
@Override
protected BTreeSearchIterator slice(Dir dir)
{
return BTree.slice(tree, comparator, lowerBound, upperBound, dir);
}
@Override
public boolean isEmpty()
{
return upperBound < lowerBound;
}
public int size()
{
return (upperBound - lowerBound) + 1;
}
boolean outOfBounds(int i)
{
return (i < lowerBound) | (i > upperBound);
}
public V get(int index)
{
index += lowerBound;
if (outOfBounds(index))
throw new NoSuchElementException();
return super.get(index);
}
public int indexOf(Object item)
{
int i = super.indexOf(item);
boolean negate = i < 0;
if (negate)
i = -1 - i;
if (outOfBounds(i))
return i < lowerBound ? -1 : -1 - size();
i = i - lowerBound;
if (negate)
i = -1 -i;
return i;
}
public V lower(V v)
{
return maybe(Math.min(upperBound, BTree.lowerIndex(tree, comparator, v)));
}
public V floor(V v)
{
return maybe(Math.min(upperBound, BTree.floorIndex(tree, comparator, v)));
}
public V ceiling(V v)
{
return maybe(Math.max(lowerBound, BTree.ceilIndex(tree, comparator, v)));
}
public V higher(V v)
{
return maybe(Math.max(lowerBound, BTree.higherIndex(tree, comparator, v)));
}
private V maybe(int i)
{
if (outOfBounds(i))
return null;
return super.get(i);
}
@Override
public BTreeSet subSet(V fromElement, boolean fromInclusive, V toElement, boolean toInclusive)
{
return new BTreeRange<>(this, new BTreeRange<>(tree, comparator, fromElement, fromInclusive, toElement, toInclusive));
}
@Override
public BTreeSet headSet(V toElement, boolean inclusive)
{
return new BTreeRange<>(this, new BTreeRange<>(tree, comparator, null, true, toElement, inclusive));
}
@Override
public BTreeSet tailSet(V fromElement, boolean inclusive)
{
return new BTreeRange<>(this, new BTreeRange<>(tree, comparator, fromElement, inclusive, null, true));
}
@Override
public BTreeSet descendingSet()
{
return new BTreeDescRange<>(this);
}
public BTreeSet subList(int fromIndex, int toIndex)
{
if (fromIndex < 0 || toIndex > size())
throw new IndexOutOfBoundsException();
return new BTreeRange(tree, comparator, lowerBound + fromIndex, lowerBound + toIndex - 1);
}
@Override
public T[] toArray(T[] a)
{
return toArray(a, 0);
}
public T[] toArray(T[] a, int offset)
{
if (size() + offset < a.length)
a = Arrays.copyOf(a, size() + offset);
BTree.toArray(tree, lowerBound, upperBound + 1, a, offset);
return a;
}
}
public static class BTreeDescRange extends BTreeRange
{
BTreeDescRange(BTreeRange from)
{
super(from.tree, from.comparator, from.lowerBound, from.upperBound);
}
@Override
protected BTreeSearchIterator slice(Dir dir)
{
return super.slice(dir.invert());
}
/* Flip the methods we call for inequality searches */
public V higher(V v)
{
return super.lower(v);
}
public V ceiling(V v)
{
return super.floor(v);
}
public V floor(V v)
{
return super.ceiling(v);
}
public V lower(V v)
{
return super.higher(v);
}
public V get(int index)
{
index = upperBound - index;
if (outOfBounds(index))
throw new NoSuchElementException();
return BTree.findByIndex(tree, index);
}
public int indexOf(Object item)
{
int i = super.indexOf(item);
// i is in range [-1 - size()..size())
// so we just need to invert by adding/subtracting from size
return i < 0 ? -2 - size() - i : size() - (i + 1);
}
public BTreeSet subList(int fromIndex, int toIndex)
{
if (fromIndex < 0 || toIndex > size())
throw new IndexOutOfBoundsException();
return new BTreeDescRange(new BTreeRange(tree, comparator, upperBound - (toIndex - 1), upperBound - fromIndex));
}
@Override
public BTreeSet subSet(V fromElement, boolean fromInclusive, V toElement, boolean toInclusive)
{
return super.subSet(toElement, toInclusive, fromElement, fromInclusive).descendingSet();
}
@Override
public BTreeSet headSet(V toElement, boolean inclusive)
{
return super.tailSet(toElement, inclusive).descendingSet();
}
@Override
public BTreeSet tailSet(V fromElement, boolean inclusive)
{
return super.headSet(fromElement, inclusive).descendingSet();
}
@Override
public BTreeSet descendingSet()
{
return new BTreeRange<>(this);
}
public Comparator comparator()
{
return (a, b) -> comparator.compare(b, a);
}
public T[] toArray(T[] a, int offset)
{
a = super.toArray(a, offset);
int count = size();
int flip = count / 2;
for (int i = 0 ; i < flip ; i++)
{
int j = count - (i + 1);
T t = a[i + offset];
a[i + offset] = a[j + offset];
a[j + offset] = t;
}
return a;
}
}
public static class Builder
{
final BTree.Builder wrapped;
protected Builder(Comparator comparator)
{
wrapped = BTree.builder(comparator);
}
protected Builder(Comparator comparator, int size)
{
wrapped = BTree.builder(comparator, size);
}
public Builder add(V v)
{
wrapped .add(v);
return this;
}
public Builder addAll(Collection iter)
{
wrapped .addAll(iter);
return this;
}
public boolean isEmpty()
{
return wrapped .isEmpty();
}
public BTreeSet build()
{
return new BTreeSet<>(wrapped .build(), wrapped .comparator);
}
}
public static Builder builder(Comparator comparator)
{
return new Builder<>(comparator);
}
/** if you know the precise size of the resultant set use {@code perfectBuilder} instead. */
public static Builder builder(Comparator comparator, int initialCapacity)
{
return new Builder<>(comparator, initialCapacity);
}
public static BTreeSet wrap(Object[] btree, Comparator comparator)
{
return new BTreeSet<>(btree, comparator);
}
public static > BTreeSet of(Collection sortedValues)
{
return new BTreeSet<>(BTree.build(sortedValues), Ordering.natural());
}
public static > BTreeSet of(V value)
{
return new BTreeSet<>(BTree.singleton(value), Ordering.natural());
}
public static BTreeSet empty(Comparator comparator)
{
return new BTreeSet<>(BTree.empty(), comparator);
}
public static BTreeSet of(Comparator comparator, V value)
{
return new BTreeSet<>(BTree.singleton(value), comparator);
}
public static BTreeSet copy(SortedSet copy, Comparator comparator)
{
try (BTree.FastBuilder builder = BTree.fastBuilder())
{
copy.forEach(builder::add);
return wrap(builder.build(), comparator);
}
}
}