com.google.common.collect.ContiguousSet Maven / Gradle / Ivy
/*
* Copyright (C) 2010 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.checkNotNull;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.util.Collections;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* A sorted set of contiguous values in a given {@link DiscreteDomain}.
*
* Warning: Be extremely careful what you do with conceptually large instances (such as
* {@code ContiguousSet.create(Range.greaterThan(0), DiscreteDomains.integers()}). Certain
* operations on such a set can be performed efficiently, but others (such as {@link Set#hashCode}
* or {@link Collections#frequency}) can cause major performance problems.
*
* @author Gregory Kick
* @since 10.0
*/
@Beta
@GwtCompatible(emulated = true)
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
public abstract class ContiguousSet extends ImmutableSortedSet {
/**
* Returns a {@code ContiguousSet} containing the same values in the given domain
* {@linkplain Range#contains contained} by the range.
*
* @throws IllegalArgumentException if neither range nor the domain has a lower bound, or if
* neither has an upper bound
*
* @since 13.0
*/
public static ContiguousSet create(
Range range, DiscreteDomain domain) {
checkNotNull(range);
checkNotNull(domain);
Range effectiveRange = range;
try {
if (!range.hasLowerBound()) {
effectiveRange = effectiveRange.intersection(Range.atLeast(domain.minValue()));
}
if (!range.hasUpperBound()) {
effectiveRange = effectiveRange.intersection(Range.atMost(domain.maxValue()));
}
} catch (NoSuchElementException e) {
throw new IllegalArgumentException(e);
}
// Per class spec, we are allowed to throw CCE if necessary
boolean empty = effectiveRange.isEmpty()
|| Range.compareOrThrow(
range.lowerBound.leastValueAbove(domain),
range.upperBound.greatestValueBelow(domain)) > 0;
return empty
? new EmptyContiguousSet(domain)
: new RegularContiguousSet(effectiveRange, domain);
}
final DiscreteDomain domain;
ContiguousSet(DiscreteDomain domain) {
super(Ordering.natural());
this.domain = domain;
}
@Override public ContiguousSet headSet(C toElement) {
return headSetImpl(checkNotNull(toElement), false);
}
/**
* @since 12.0
*/
@GwtIncompatible("NavigableSet")
@Override public ContiguousSet headSet(C toElement, boolean inclusive) {
return headSetImpl(checkNotNull(toElement), inclusive);
}
@Override public ContiguousSet subSet(C fromElement, C toElement) {
checkNotNull(fromElement);
checkNotNull(toElement);
checkArgument(comparator().compare(fromElement, toElement) <= 0);
return subSetImpl(fromElement, true, toElement, false);
}
/**
* @since 12.0
*/
@GwtIncompatible("NavigableSet")
@Override public ContiguousSet subSet(C fromElement, boolean fromInclusive, C toElement,
boolean toInclusive) {
checkNotNull(fromElement);
checkNotNull(toElement);
checkArgument(comparator().compare(fromElement, toElement) <= 0);
return subSetImpl(fromElement, fromInclusive, toElement, toInclusive);
}
@Override public ContiguousSet tailSet(C fromElement) {
return tailSetImpl(checkNotNull(fromElement), true);
}
/**
* @since 12.0
*/
@GwtIncompatible("NavigableSet")
@Override public ContiguousSet tailSet(C fromElement, boolean inclusive) {
return tailSetImpl(checkNotNull(fromElement), inclusive);
}
/*
* These methods perform most headSet, subSet, and tailSet logic, besides parameter validation.
*/
/*@Override*/ abstract ContiguousSet headSetImpl(C toElement, boolean inclusive);
/*@Override*/ abstract ContiguousSet subSetImpl(C fromElement, boolean fromInclusive,
C toElement, boolean toInclusive);
/*@Override*/ abstract ContiguousSet tailSetImpl(C fromElement, boolean inclusive);
/**
* Returns the set of values that are contained in both this set and the other.
*
* This method should always be used instead of
* {@link Sets#intersection} for {@link ContiguousSet} instances.
*/
public abstract ContiguousSet intersection(ContiguousSet other);
/**
* Returns a range, closed on both ends, whose endpoints are the minimum and maximum values
* contained in this set. This is equivalent to {@code range(CLOSED, CLOSED)}.
*
* @throws NoSuchElementException if this set is empty
*/
public abstract Range range();
/**
* Returns the minimal range with the given boundary types for which all values in this set are
* {@linkplain Range#contains(Comparable) contained} within the range.
*
* Note that this method will return ranges with unbounded endpoints if {@link BoundType#OPEN}
* is requested for a domain minimum or maximum. For example, if {@code set} was created from the
* range {@code [1..Integer.MAX_VALUE]} then {@code set.range(CLOSED, OPEN)} must return
* {@code [1..∞)}.
*
* @throws NoSuchElementException if this set is empty
*/
public abstract Range range(BoundType lowerBoundType, BoundType upperBoundType);
/** Returns a short-hand representation of the contents such as {@code "[1..100]"}. */
@Override public String toString() {
return range().toString();
}
}