/*
* 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 com.google.common.annotations.GwtCompatible;
import com.google.common.base.Objects;
import java.io.Serializable;
import java.util.Comparator;
import javax.annotation.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.
*
* <p>Whenever possible, use {@code Range} instead, which is better supported.
*
* @author Louis Wasserman
*/
@GwtCompatible(serializable = true)
final class GeneralRange<T> implements Serializable {
/**
* Converts a Range to a GeneralRange.
*/
static <T extends Comparable> GeneralRange<T> from(Range<T> range) {
@Nullable
T lowerEndpoint = range.hasLowerBound() ? range.lowerEndpoint() : null;
BoundType lowerBoundType = range.hasLowerBound() ? range.lowerBoundType() : OPEN;
@Nullable
T upperEndpoint = range.hasUpperBound() ? range.upperEndpoint() : null;
BoundType upperBoundType = range.hasUpperBound() ? range.upperBoundType() : OPEN;
return new GeneralRange<T>(Ordering.natural(), range.hasLowerBound(), lowerEndpoint,
lowerBoundType, range.hasUpperBound(), upperEndpoint, upperBoundType);
}
/**
* Returns the whole range relative to the specified comparator.
*/
static <T> GeneralRange<T> all(Comparator<? super T> comparator) {
return new GeneralRange<T>(comparator, false, null, OPEN, false, null, OPEN);
}
/**
* Returns everything above the endpoint relative to the specified comparator, with the specified
* endpoint behavior.
*/
static <T> GeneralRange<T> downTo(Comparator<? super T> comparator, @Nullable T endpoint,
BoundType boundType) {
return new GeneralRange<T>(comparator, true, endpoint, boundType, false, null, OPEN);
}
/**
* Returns everything below the endpoint relative to the specified comparator, with the specified
* endpoint behavior.
*/
static <T> GeneralRange<T> upTo(Comparator<? super T> comparator, @Nullable T endpoint,
BoundType boundType) {
return new GeneralRange<T>(comparator, false, null, OPEN, true, endpoint, boundType);
}
/**
* Returns everything between the endpoints relative to the specified comparator, with the
* specified endpoint behavior.
*/
static <T> GeneralRange<T> range(Comparator<? super T> comparator, @Nullable T lower,
BoundType lowerType, @Nullable T upper, BoundType upperType) {
return new GeneralRange<T>(comparator, true, lower, lowerType, true, upper, upperType);
}
private final Comparator<? super T> comparator;
private final boolean hasLowerBound;
@Nullable
private final T lowerEndpoint;
private final BoundType lowerBoundType;
private final boolean hasUpperBound;
@Nullable
private final T upperEndpoint;
private final BoundType upperBoundType;
private GeneralRange(Comparator<? super T> comparator, boolean hasLowerBound,
@Nullable T lowerEndpoint, BoundType lowerBoundType, boolean hasUpperBound,
@Nullable 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);
if (hasLowerBound) {
comparator.compare(lowerEndpoint, lowerEndpoint);
}
if (hasUpperBound) {
comparator.compare(upperEndpoint, upperEndpoint);
}
if (hasLowerBound && hasUpperBound) {
int cmp = comparator.compare(lowerEndpoint, upperEndpoint);
// be consistent with Range
checkArgument(cmp <= 0, "lowerEndpoint (%s) > upperEndpoint (%s)", lowerEndpoint,
upperEndpoint);
if (cmp == 0) {
checkArgument(lowerBoundType != OPEN | upperBoundType != OPEN);
}
}
}
Comparator<? super T> comparator() {
return comparator;
}
boolean hasLowerBound() {
return hasLowerBound;
}
boolean hasUpperBound() {
return hasUpperBound;
}
boolean isEmpty() {
return (hasUpperBound() && tooLow(getUpperEndpoint()))
|| (hasLowerBound() && tooHigh(getLowerEndpoint()));
}
boolean tooLow(@Nullable T t) {
if (!hasLowerBound()) {
return false;
}
T lbound = getLowerEndpoint();
int cmp = comparator.compare(t, lbound);
return cmp < 0 | (cmp == 0 & getLowerBoundType() == OPEN);
}
boolean tooHigh(@Nullable T t) {
if (!hasUpperBound()) {
return false;
}
T ubound = getUpperEndpoint();
int cmp = comparator.compare(t, ubound);
return cmp > 0 | (cmp == 0 & getUpperBoundType() == OPEN);
}
boolean contains(@Nullable T t) {
return !tooLow(t) && !tooHigh(t);
}
/**
* Returns the intersection of the two ranges, or an empty range if their intersection is empty.
*/
GeneralRange<T> intersect(GeneralRange<T> other) {
checkNotNull(other);
checkArgument(comparator.equals(other.comparator));
boolean hasLowBound = this.hasLowerBound;
@Nullable
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;
@Nullable
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<T>(comparator, hasLowBound, lowEnd, lowType, hasUpBound, upEnd, upType);
}
@Override
public boolean equals(@Nullable 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());
}
private transient GeneralRange<T> reverse;
/**
* Returns the same range relative to the reversed comparator.
*/
GeneralRange<T> reverse() {
GeneralRange<T> result = reverse;
if (result == null) {
result = new GeneralRange<T>(
Ordering.from(comparator).reverse(), hasUpperBound, getUpperEndpoint(),
getUpperBoundType(), hasLowerBound, getLowerEndpoint(), getLowerBoundType());
result.reverse = this;
return this.reverse = result;
}
return result;
}
@Override
public String toString() {
return new StringBuilder()
.append(comparator)
.append(":")
.append(lowerBoundType == CLOSED ? '[' : '(')
.append(hasLowerBound ? lowerEndpoint : "-\u221e")
.append(',')
.append(hasUpperBound ? upperEndpoint : "\u221e")
.append(upperBoundType == CLOSED ? ']' : ')')
.toString();
}
T getLowerEndpoint() {
return lowerEndpoint;
}
BoundType getLowerBoundType() {
return lowerBoundType;
}
T getUpperEndpoint() {
return upperEndpoint;
}
BoundType getUpperBoundType() {
return upperBoundType;
}
}