com.google.common.collect.GeneralRange Maven / Gradle / Ivy
/*
* 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.checkNotNull;
import static com.google.common.collect.BoundType.CLOSED;
import static com.google.common.collect.BoundType.OPEN;
import static com.google.common.collect.NullnessCasts.uncheckedCastNullableTToT;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Objects;
import com.google.errorprone.annotations.concurrent.LazyInit;
import java.io.Serializable;
import java.util.Comparator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* A generalized interval on any ordering, for internal use. Supports {@code null}. Unlike {@link
* Range}, this allows the use of an arbitrary comparator. This is designed for use in the
* implementation of subcollections of sorted collection types.
*
* Whenever possible, use {@code Range} instead, which is better supported.
*
* @author Louis Wasserman
*/
@GwtCompatible(serializable = true)
@ElementTypesAreNonnullByDefault
final class GeneralRange implements Serializable {
/** Converts a Range to a GeneralRange. */
static GeneralRange from(Range range) {
T lowerEndpoint = range.hasLowerBound() ? range.lowerEndpoint() : null;
BoundType lowerBoundType = range.hasLowerBound() ? range.lowerBoundType() : OPEN;
T upperEndpoint = range.hasUpperBound() ? range.upperEndpoint() : null;
BoundType upperBoundType = range.hasUpperBound() ? range.upperBoundType() : OPEN;
return new GeneralRange<>(
Ordering.natural(),
range.hasLowerBound(),
lowerEndpoint,
lowerBoundType,
range.hasUpperBound(),
upperEndpoint,
upperBoundType);
}
/** Returns the whole range relative to the specified comparator. */
static GeneralRange all(Comparator comparator) {
return new GeneralRange<>(comparator, false, null, OPEN, false, null, OPEN);
}
/**
* Returns everything above the endpoint relative to the specified comparator, with the specified
* endpoint behavior.
*/
static GeneralRange downTo(
Comparator comparator, @ParametricNullness T endpoint, BoundType boundType) {
return new GeneralRange<>(comparator, true, endpoint, boundType, false, null, OPEN);
}
/**
* Returns everything below the endpoint relative to the specified comparator, with the specified
* endpoint behavior.
*/
static GeneralRange upTo(
Comparator comparator, @ParametricNullness T endpoint, BoundType boundType) {
return new GeneralRange<>(comparator, false, null, OPEN, true, endpoint, boundType);
}
/**
* Returns everything between the endpoints relative to the specified comparator, with the
* specified endpoint behavior.
*/
static GeneralRange range(
Comparator comparator,
@ParametricNullness T lower,
BoundType lowerType,
@ParametricNullness T upper,
BoundType upperType) {
return new GeneralRange<>(comparator, true, lower, lowerType, true, upper, upperType);
}
private final Comparator comparator;
private final boolean hasLowerBound;
@CheckForNull private final T lowerEndpoint;
private final BoundType lowerBoundType;
private final boolean hasUpperBound;
@CheckForNull private final T upperEndpoint;
private final BoundType upperBoundType;
private GeneralRange(
Comparator comparator,
boolean hasLowerBound,
@CheckForNull T lowerEndpoint,
BoundType lowerBoundType,
boolean hasUpperBound,
@CheckForNull T upperEndpoint,
BoundType upperBoundType) {
this.comparator = checkNotNull(comparator);
this.hasLowerBound = hasLowerBound;
this.hasUpperBound = hasUpperBound;
this.lowerEndpoint = lowerEndpoint;
this.lowerBoundType = checkNotNull(lowerBoundType);
this.upperEndpoint = upperEndpoint;
this.upperBoundType = checkNotNull(upperBoundType);
// Trigger any exception that the comparator would throw for the endpoints.
/*
* uncheckedCastNullableTToT is safe as long as the callers are careful to pass a "real" T
* whenever they pass `true` for the matching `has*Bound` parameter.
*/
if (hasLowerBound) {
int unused =
comparator.compare(
uncheckedCastNullableTToT(lowerEndpoint), uncheckedCastNullableTToT(lowerEndpoint));
}
if (hasUpperBound) {
int unused =
comparator.compare(
uncheckedCastNullableTToT(upperEndpoint), uncheckedCastNullableTToT(upperEndpoint));
}
if (hasLowerBound && hasUpperBound) {
int cmp =
comparator.compare(
uncheckedCastNullableTToT(lowerEndpoint), uncheckedCastNullableTToT(upperEndpoint));
// be consistent with Range
checkArgument(
cmp <= 0, "lowerEndpoint (%s) > upperEndpoint (%s)", lowerEndpoint, upperEndpoint);
if (cmp == 0) {
checkArgument(lowerBoundType != OPEN || upperBoundType != OPEN);
}
}
}
Comparator comparator() {
return comparator;
}
boolean hasLowerBound() {
return hasLowerBound;
}
boolean hasUpperBound() {
return hasUpperBound;
}
boolean isEmpty() {
// The casts are safe because of the has*Bound() checks.
return (hasUpperBound() && tooLow(uncheckedCastNullableTToT(getUpperEndpoint())))
|| (hasLowerBound() && tooHigh(uncheckedCastNullableTToT(getLowerEndpoint())));
}
boolean tooLow(@ParametricNullness T t) {
if (!hasLowerBound()) {
return false;
}
// The cast is safe because of the hasLowerBound() check.
T lbound = uncheckedCastNullableTToT(getLowerEndpoint());
int cmp = comparator.compare(t, lbound);
return cmp < 0 | (cmp == 0 & getLowerBoundType() == OPEN);
}
boolean tooHigh(@ParametricNullness T t) {
if (!hasUpperBound()) {
return false;
}
// The cast is safe because of the hasUpperBound() check.
T ubound = uncheckedCastNullableTToT(getUpperEndpoint());
int cmp = comparator.compare(t, ubound);
return cmp > 0 | (cmp == 0 & getUpperBoundType() == OPEN);
}
boolean contains(@ParametricNullness T t) {
return !tooLow(t) && !tooHigh(t);
}
/**
* Returns the intersection of the two ranges, or an empty range if their intersection is empty.
*/
@SuppressWarnings("nullness") // TODO(cpovirk): Add casts as needed. Will be noisy and annoying...
GeneralRange intersect(GeneralRange other) {
checkNotNull(other);
checkArgument(comparator.equals(other.comparator));
boolean hasLowBound = this.hasLowerBound;
T lowEnd = getLowerEndpoint();
BoundType lowType = getLowerBoundType();
if (!hasLowerBound()) {
hasLowBound = other.hasLowerBound;
lowEnd = other.getLowerEndpoint();
lowType = other.getLowerBoundType();
} else if (other.hasLowerBound()) {
int cmp = comparator.compare(getLowerEndpoint(), other.getLowerEndpoint());
if (cmp < 0 || (cmp == 0 && other.getLowerBoundType() == OPEN)) {
lowEnd = other.getLowerEndpoint();
lowType = other.getLowerBoundType();
}
}
boolean hasUpBound = this.hasUpperBound;
T upEnd = getUpperEndpoint();
BoundType upType = getUpperBoundType();
if (!hasUpperBound()) {
hasUpBound = other.hasUpperBound;
upEnd = other.getUpperEndpoint();
upType = other.getUpperBoundType();
} else if (other.hasUpperBound()) {
int cmp = comparator.compare(getUpperEndpoint(), other.getUpperEndpoint());
if (cmp > 0 || (cmp == 0 && other.getUpperBoundType() == OPEN)) {
upEnd = other.getUpperEndpoint();
upType = other.getUpperBoundType();
}
}
if (hasLowBound && hasUpBound) {
int cmp = comparator.compare(lowEnd, upEnd);
if (cmp > 0 || (cmp == 0 && lowType == OPEN && upType == OPEN)) {
// force allowed empty range
lowEnd = upEnd;
lowType = OPEN;
upType = CLOSED;
}
}
return new GeneralRange<>(comparator, hasLowBound, lowEnd, lowType, hasUpBound, upEnd, upType);
}
@Override
public boolean equals(@CheckForNull Object obj) {
if (obj instanceof GeneralRange) {
GeneralRange r = (GeneralRange) obj;
return comparator.equals(r.comparator)
&& hasLowerBound == r.hasLowerBound
&& hasUpperBound == r.hasUpperBound
&& getLowerBoundType().equals(r.getLowerBoundType())
&& getUpperBoundType().equals(r.getUpperBoundType())
&& Objects.equal(getLowerEndpoint(), r.getLowerEndpoint())
&& Objects.equal(getUpperEndpoint(), r.getUpperEndpoint());
}
return false;
}
@Override
public int hashCode() {
return Objects.hashCode(
comparator,
getLowerEndpoint(),
getLowerBoundType(),
getUpperEndpoint(),
getUpperBoundType());
}
@LazyInit @CheckForNull private transient GeneralRange reverse;
/** Returns the same range relative to the reversed comparator. */
GeneralRange reverse() {
GeneralRange result = reverse;
if (result == null) {
result =
new GeneralRange<>(
Ordering.from(comparator).reverse(),
hasUpperBound,
getUpperEndpoint(),
getUpperBoundType(),
hasLowerBound,
getLowerEndpoint(),
getLowerBoundType());
result.reverse = this;
return this.reverse = result;
}
return result;
}
@Override
public String toString() {
return comparator
+ ":"
+ (lowerBoundType == CLOSED ? '[' : '(')
+ (hasLowerBound ? lowerEndpoint : "-\u221e")
+ ','
+ (hasUpperBound ? upperEndpoint : "\u221e")
+ (upperBoundType == CLOSED ? ']' : ')');
}
@CheckForNull
T getLowerEndpoint() {
return lowerEndpoint;
}
BoundType getLowerBoundType() {
return lowerBoundType;
}
@CheckForNull
T getUpperEndpoint() {
return upperEndpoint;
}
BoundType getUpperBoundType() {
return upperBoundType;
}
}