/*
 * Copyright (C) 2011 The Guava Authors
 *
 * 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 com.google.common.collect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.BoundType.CLOSED;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.io.Serializable;
import java.util.Collection;
import org.checkerframework.checker.nullness.qual.Nullable;

An implementation of ContiguousSet that contains one or more elements.
Author:Gregory Kick
/** * An implementation of {@link ContiguousSet} that contains one or more elements. * * @author Gregory Kick */
@GwtCompatible(emulated = true) @SuppressWarnings("unchecked") // allow ungenerified Comparable types final class RegularContiguousSet<C extends Comparable> extends ContiguousSet<C> { private final Range<C> range; RegularContiguousSet(Range<C> range, DiscreteDomain<C> domain) { super(domain); this.range = range; } private ContiguousSet<C> intersectionInCurrentDomain(Range<C> other) { return (range.isConnected(other)) ? ContiguousSet.create(range.intersection(other), domain) : new EmptyContiguousSet<C>(domain); } @Override ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) { return intersectionInCurrentDomain(Range.upTo(toElement, BoundType.forBoolean(inclusive))); } @Override ContiguousSet<C> subSetImpl( C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) { if (fromElement.compareTo(toElement) == 0 && !fromInclusive && !toInclusive) { // Range would reject our attempt to create (x, x). return new EmptyContiguousSet<C>(domain); } return intersectionInCurrentDomain( Range.range( fromElement, BoundType.forBoolean(fromInclusive), toElement, BoundType.forBoolean(toInclusive))); } @Override ContiguousSet<C> tailSetImpl(C fromElement, boolean inclusive) { return intersectionInCurrentDomain(Range.downTo(fromElement, BoundType.forBoolean(inclusive))); } @GwtIncompatible // not used by GWT emulation @Override int indexOf(Object target) { return contains(target) ? (int) domain.distance(first(), (C) target) : -1; } @Override public UnmodifiableIterator<C> iterator() { return new AbstractSequentialIterator<C>(first()) { final C last = last(); @Override protected C computeNext(C previous) { return equalsOrThrow(previous, last) ? null : domain.next(previous); } }; } @GwtIncompatible // NavigableSet @Override public UnmodifiableIterator<C> descendingIterator() { return new AbstractSequentialIterator<C>(last()) { final C first = first(); @Override protected C computeNext(C previous) { return equalsOrThrow(previous, first) ? null : domain.previous(previous); } }; } private static boolean equalsOrThrow(Comparable<?> left, @Nullable Comparable<?> right) { return right != null && Range.compareOrThrow(left, right) == 0; } @Override boolean isPartialView() { return false; } @Override public C first() { return range.lowerBound.leastValueAbove(domain); } @Override public C last() { return range.upperBound.greatestValueBelow(domain); } @Override ImmutableList<C> createAsList() { if (domain.supportsFastOffset) { return new ImmutableAsList<C>() { @Override ImmutableSortedSet<C> delegateCollection() { return RegularContiguousSet.this; } @Override public C get(int i) { checkElementIndex(i, size()); return domain.offset(first(), i); } }; } else { return super.createAsList(); } } @Override public int size() { long distance = domain.distance(first(), last()); return (distance >= Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int) distance + 1; } @Override public boolean contains(@Nullable Object object) { if (object == null) { return false; } try { return range.contains((C) object); } catch (ClassCastException e) { return false; } } @Override public boolean containsAll(Collection<?> targets) { return Collections2.containsAllImpl(this, targets); } @Override public boolean isEmpty() { return false; } @Override public ContiguousSet<C> intersection(ContiguousSet<C> other) { checkNotNull(other); checkArgument(this.domain.equals(other.domain)); if (other.isEmpty()) { return other; } else { C lowerEndpoint = Ordering.natural().max(this.first(), other.first()); C upperEndpoint = Ordering.natural().min(this.last(), other.last()); return (lowerEndpoint.compareTo(upperEndpoint) <= 0) ? ContiguousSet.create(Range.closed(lowerEndpoint, upperEndpoint), domain) : new EmptyContiguousSet<C>(domain); } } @Override public Range<C> range() { return range(CLOSED, CLOSED); } @Override public Range<C> range(BoundType lowerBoundType, BoundType upperBoundType) { return Range.create( range.lowerBound.withLowerBoundType(lowerBoundType, domain), range.upperBound.withUpperBoundType(upperBoundType, domain)); } @Override public boolean equals(@Nullable Object object) { if (object == this) { return true; } else if (object instanceof RegularContiguousSet) { RegularContiguousSet<?> that = (RegularContiguousSet<?>) object; if (this.domain.equals(that.domain)) { return this.first().equals(that.first()) && this.last().equals(that.last()); } } return super.equals(object); } // copied to make sure not to use the GWT-emulated version @Override public int hashCode() { return Sets.hashCodeImpl(this); } @GwtIncompatible // serialization private static final class SerializedForm<C extends Comparable> implements Serializable { final Range<C> range; final DiscreteDomain<C> domain; private SerializedForm(Range<C> range, DiscreteDomain<C> domain) { this.range = range; this.domain = domain; } private Object readResolve() { return new RegularContiguousSet<C>(range, domain); } } @GwtIncompatible // serialization @Override Object writeReplace() { return new SerializedForm<C>(range, domain); } private static final long serialVersionUID = 0; }