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/*
* Copyright (C) 2002-2021 Sebastiano Vigna
*
* Licensed 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 it.unimi.dsi.fastutil.longs;
import java.util.Collection;
import java.util.Set;
import java.util.function.Consumer;
/**
* A class providing static methods and objects that do useful things with
* type-specific sets.
*
* @see java.util.Collections
*/
public final class LongSets {
private LongSets() {
}
/**
* The maximum size to choose ArraySet over OpenHashSet for utilites that
* automatically choose.
*/
static final int ARRAY_SET_CUTOFF = 4;
/**
* An immutable class representing the empty set and implementing a
* type-specific set interface.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific set.
*/
public static class EmptySet extends LongCollections.EmptyCollection
implements
LongSet,
java.io.Serializable,
Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptySet() {
}
@Override
public boolean remove(long ok) {
throw new UnsupportedOperationException();
}
@Override
public Object clone() {
return EMPTY_SET;
}
@Override
@SuppressWarnings("rawtypes")
public boolean equals(final Object o) {
return o instanceof Set && ((Set) o).isEmpty();
}
@Deprecated
@Override
public boolean rem(final long k) {
return super.rem(k);
}
private Object readResolve() {
return EMPTY_SET;
}
}
/**
* An empty set (immutable). It is serializable and cloneable.
*/
public static final EmptySet EMPTY_SET = new EmptySet();
// Used by Sets.of() instead of SETS.EMPTY_SET to make a dimorphic call site.
// See https://github.com/vigna/fastutil/issues/183
static final LongSet UNMODIFIABLE_EMPTY_SET = LongSets.unmodifiable(new LongArraySet(LongArrays.EMPTY_ARRAY));
/**
* Returns an empty set (immutable). It is serializable and cloneable.
*
*
* This method provides a typesafe access to {@link #EMPTY_SET}.
*
* @return an empty set (immutable).
*/
@SuppressWarnings("unchecked")
public static LongSet emptySet() {
return EMPTY_SET;
}
/**
* An immutable class representing a type-specific singleton set.
*
*
* This class may be useful to implement your own in case you subclass a
* type-specific set.
*/
public static class Singleton extends AbstractLongSet implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected final long element;
protected Singleton(final long element) {
this.element = element;
}
@Override
public boolean contains(final long k) {
return ((k) == (element));
}
@Override
public boolean remove(final long k) {
throw new UnsupportedOperationException();
}
@Override
public LongListIterator iterator() {
return LongIterators.singleton(element);
}
@Override
public LongSpliterator spliterator() {
return LongSpliterators.singleton(element);
}
@Override
public int size() {
return 1;
}
@Override
public long[] toLongArray() {
return new long[]{element};
}
@Deprecated
@Override
public void forEach(final Consumer action) {
action.accept(Long.valueOf(element));
}
@Override
public boolean addAll(final Collection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(final Collection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(final Collection c) {
throw new UnsupportedOperationException();
}
@Deprecated
@Override
public boolean removeIf(final java.util.function.Predicate filter) {
throw new UnsupportedOperationException();
}
@Override
public void forEach(final java.util.function.LongConsumer action) {
action.accept(element);
}
@Override
public boolean addAll(final LongCollection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(final LongCollection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(final LongCollection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeIf(final java.util.function.LongPredicate filter) {
throw new UnsupportedOperationException();
}
@Deprecated
@Override
public Object[] toArray() {
return new Object[]{Long.valueOf(element)};
}
@Override
public Object clone() {
return this;
}
}
/**
* Returns a type-specific immutable set containing only the specified element.
* The returned set is serializable and cloneable.
*
* @param element
* the only element of the returned set.
* @return a type-specific immutable set containing just {@code element}.
*/
public static LongSet singleton(final long element) {
return new Singleton(element);
}
/**
* Returns a type-specific immutable set containing only the specified element.
* The returned set is serializable and cloneable.
*
* @param element
* the only element of the returned set.
* @return a type-specific immutable set containing just {@code element}.
*/
public static LongSet singleton(final Long element) {
return new Singleton((element).longValue());
}
/** A synchronized wrapper class for sets. */
public static class SynchronizedSet extends LongCollections.SynchronizedCollection
implements
LongSet,
java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected SynchronizedSet(final LongSet s, final Object sync) {
super(s, sync);
}
protected SynchronizedSet(final LongSet s) {
super(s);
}
@Override
public boolean remove(final long k) {
synchronized (sync) {
return collection.rem(k);
}
}
@Deprecated
@Override
public boolean rem(final long k) {
return super.rem(k);
}
}
/**
* Returns a synchronized type-specific set backed by the given type-specific
* set.
*
* @param s
* the set to be wrapped in a synchronized set.
* @return a synchronized view of the specified set.
* @see java.util.Collections#synchronizedSet(Set)
*/
public static LongSet synchronize(final LongSet s) {
return new SynchronizedSet(s);
}
/**
* Returns a synchronized type-specific set backed by the given type-specific
* set, using an assigned object to synchronize.
*
* @param s
* the set to be wrapped in a synchronized set.
* @param sync
* an object that will be used to synchronize the access to the set.
* @return a synchronized view of the specified set.
* @see java.util.Collections#synchronizedSet(Set)
*/
public static LongSet synchronize(final LongSet s, final Object sync) {
return new SynchronizedSet(s, sync);
}
/** An unmodifiable wrapper class for sets. */
public static class UnmodifiableSet extends LongCollections.UnmodifiableCollection
implements
LongSet,
java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected UnmodifiableSet(final LongSet s) {
super(s);
}
@Override
public boolean remove(final long k) {
throw new UnsupportedOperationException();
}
@Override
public boolean equals(final Object o) {
if (o == this)
return true;
return collection.equals(o);
}
@Override
public int hashCode() {
return collection.hashCode();
}
@Deprecated
@Override
public boolean rem(final long k) {
return super.rem(k);
}
}
/**
* Returns an unmodifiable type-specific set backed by the given type-specific
* set.
*
* @param s
* the set to be wrapped in an unmodifiable set.
* @return an unmodifiable view of the specified set.
* @see java.util.Collections#unmodifiableSet(Set)
*/
public static LongSet unmodifiable(final LongSet s) {
return new UnmodifiableSet(s);
}
/**
* Returns an unmodifiable type-specific set containing elements in the given
* range.
*
* @param from
* the starting element (lower bound) of the set (inclusive).
* @param to
* the ending element (upper bound) of the set (exclusive).
* @return an unmodifiable set containing the elements in the given range.
*/
public static LongSet fromTo(final long from, final long to) {
return new AbstractLongSet() {
@Override
public boolean contains(final long x) {
return x >= from && x < to;
}
@Override
public LongIterator iterator() {
return LongIterators.fromTo(from, to);
}
@Override
public int size() {
final long size = to - from;
return size >= 0 && size <= Integer.MAX_VALUE ? (int) size : Integer.MAX_VALUE;
}
};
}
/**
* Returns an unmodifiable type-specific set containing elements greater than or
* equal to a given element.
*
* @param from
* the starting element (lower bound) of the set (inclusive).
* @return an unmodifiable set containing the elements greater than or equal to
* {@code from}.
*/
public static LongSet from(final long from) {
return new AbstractLongSet() {
@Override
public boolean contains(final long x) {
return x >= from;
}
@Override
public LongIterator iterator() {
return LongIterators.concat(new LongIterator[]{LongIterators.fromTo(from, Long.MAX_VALUE),
LongSets.singleton(Long.MAX_VALUE).iterator()});
}
@Override
public int size() {
final long size = Long.MAX_VALUE - from + 1;
return size >= 0 && size <= Integer.MAX_VALUE ? (int) size : Integer.MAX_VALUE;
}
};
}
/**
* Returns an unmodifiable type-specific set containing elements smaller than a
* given element.
*
* @param to
* the ending element (upper bound) of the set (exclusive).
* @return an unmodifiable set containing the elements smaller than {@code to}.
*/
public static LongSet to(final long to) {
return new AbstractLongSet() {
@Override
public boolean contains(final long x) {
return x < to;
}
@Override
public LongIterator iterator() {
return LongIterators.fromTo(Long.MIN_VALUE, to);
}
@Override
public int size() {
final long size = to - Long.MIN_VALUE;
return size >= 0 && size <= Integer.MAX_VALUE ? (int) size : Integer.MAX_VALUE;
}
};
}
}