/*
* Copyright (C) 2009 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.checkNotNull;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Static methods pertaining to {@link Range} instances. Each of the
* {@link Range nine types of ranges} can be constructed with a corresponding
* factory method:
*
* <dl>
* <dt>{@code (a..b)}
* <dd>{@link #open}
* <dt>{@code [a..b]}
* <dd>{@link #closed}
* <dt>{@code [a..b)}
* <dd>{@link #closedOpen}
* <dt>{@code (a..b]}
* <dd>{@link #openClosed}
* <dt>{@code (a..+∞)}
* <dd>{@link #greaterThan}
* <dt>{@code [a..+∞)}
* <dd>{@link #atLeast}
* <dt>{@code (-∞..b)}
* <dd>{@link #lessThan}
* <dt>{@code (-∞..b]}
* <dd>{@link #atMost}
* <dt>{@code (-∞..+∞)}
* <dd>{@link #all}
* </dl>
*
* <p>Additionally, {@link Range} instances can be constructed by passing the
* {@link BoundType bound types} explicitly.
*
* <dl>
* <dt>Bounded on both ends
* <dd>{@link #range}
* <dt>Unbounded on top ({@code (a..+∞)} or {@code (a..+∞)})
* <dd>{@link #downTo}
* <dt>Unbounded on bottom ({@code (-∞..b)} or {@code (-∞..b]})
* <dd>{@link #upTo}
* </dl>
*
* <p>See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/RangesExplained">
* {@code Range}</a>.
*
* @author Kevin Bourrillion
* @author Gregory Kick
* @since 10.0
*/
@GwtCompatible
@Beta
public final class Ranges {
private Ranges() {}
static <C extends Comparable<?>> Range<C> create(
Cut<C> lowerBound, Cut<C> upperBound) {
return new Range<C>(lowerBound, upperBound);
}
/**
* Returns a range that contains all values strictly greater than {@code
* lower} and strictly less than {@code upper}.
*
* @throws IllegalArgumentException if {@code lower} is greater than <i>or
* equal to</i> {@code upper}
*/
public static <C extends Comparable<?>> Range<C> open(C lower, C upper) {
return create(Cut.aboveValue(lower), Cut.belowValue(upper));
}
/**
* Returns a range that contains all values greater than or equal to
* {@code lower} and less than or equal to {@code upper}.
*
* @throws IllegalArgumentException if {@code lower} is greater than {@code
* upper}
*/
public static <C extends Comparable<?>> Range<C> closed(C lower, C upper) {
return create(Cut.belowValue(lower), Cut.aboveValue(upper));
}
/**
* Returns a range that contains all values greater than or equal to
* {@code lower} and strictly less than {@code upper}.
*
* @throws IllegalArgumentException if {@code lower} is greater than {@code
* upper}
*/
public static <C extends Comparable<?>> Range<C> closedOpen(
C lower, C upper) {
return create(Cut.belowValue(lower), Cut.belowValue(upper));
}
/**
* Returns a range that contains all values strictly greater than {@code
* lower} and less than or equal to {@code upper}.
*
* @throws IllegalArgumentException if {@code lower} is greater than {@code
* upper}
*/
public static <C extends Comparable<?>> Range<C> openClosed(
C lower, C upper) {
return create(Cut.aboveValue(lower), Cut.aboveValue(upper));
}
/**
* Returns a range that contains any value from {@code lower} to {@code
* upper}, where each endpoint may be either inclusive (closed) or exclusive
* (open).
*
* @throws IllegalArgumentException if {@code lower} is greater than {@code
* upper}
*/
public static <C extends Comparable<?>> Range<C> range(
C lower, BoundType lowerType, C upper, BoundType upperType) {
checkNotNull(lowerType);
checkNotNull(upperType);
Cut<C> lowerBound = (lowerType == BoundType.OPEN)
? Cut.aboveValue(lower)
: Cut.belowValue(lower);
Cut<C> upperBound = (upperType == BoundType.OPEN)
? Cut.belowValue(upper)
: Cut.aboveValue(upper);
return create(lowerBound, upperBound);
}
/**
* Returns a range that contains all values strictly less than {@code
* endpoint}.
*/
public static <C extends Comparable<?>> Range<C> lessThan(C endpoint) {
return create(Cut.<C>belowAll(), Cut.belowValue(endpoint));
}
/**
* Returns a range that contains all values less than or equal to
* {@code endpoint}.
*/
public static <C extends Comparable<?>> Range<C> atMost(C endpoint) {
return create(Cut.<C>belowAll(), Cut.aboveValue(endpoint));
}
/**
* Returns a range with no lower bound up to the given endpoint, which may be
* either inclusive (closed) or exclusive (open).
*/
public static <C extends Comparable<?>> Range<C> upTo(
C endpoint, BoundType boundType) {
switch (boundType) {
case OPEN:
return lessThan(endpoint);
case CLOSED:
return atMost(endpoint);
default:
throw new AssertionError();
}
}
/**
* Returns a range that contains all values strictly greater than {@code
* endpoint}.
*/
public static <C extends Comparable<?>> Range<C> greaterThan(C endpoint) {
return create(Cut.aboveValue(endpoint), Cut.<C>aboveAll());
}
/**
* Returns a range that contains all values greater than or equal to
* {@code endpoint}.
*/
public static <C extends Comparable<?>> Range<C> atLeast(C endpoint) {
return create(Cut.belowValue(endpoint), Cut.<C>aboveAll());
}
/**
* Returns a range from the given endpoint, which may be either inclusive
* (closed) or exclusive (open), with no upper bound.
*/
public static <C extends Comparable<?>> Range<C> downTo(
C endpoint, BoundType boundType) {
switch (boundType) {
case OPEN:
return greaterThan(endpoint);
case CLOSED:
return atLeast(endpoint);
default:
throw new AssertionError();
}
}
/** Returns a range that contains every value of type {@code C}. */
public static <C extends Comparable<?>> Range<C> all() {
return create(Cut.<C>belowAll(), Cut.<C>aboveAll());
}
/**
* Returns a range that {@linkplain Range#contains(Comparable) contains} only
* the given value. The returned range is {@linkplain BoundType#CLOSED closed}
* on both ends.
*/
public static <C extends Comparable<?>> Range<C> singleton(C value) {
return closed(value, value);
}
/**
* Returns the minimal range that
* {@linkplain Range#contains(Comparable) contains} all of the given values.
* The returned range is {@linkplain BoundType#CLOSED closed} on both ends.
*
* @throws ClassCastException if the parameters are not <i>mutually
* comparable</i>
* @throws NoSuchElementException if {@code values} is empty
* @throws NullPointerException if any of {@code values} is null
*/
public static <C extends Comparable<?>> Range<C> encloseAll(
Iterable<C> values) {
checkNotNull(values);
if (values instanceof ContiguousSet) {
return ((ContiguousSet<C>) values).range();
}
Iterator<C> valueIterator = values.iterator();
C min = checkNotNull(valueIterator.next());
C max = min;
while (valueIterator.hasNext()) {
C value = checkNotNull(valueIterator.next());
min = Ordering.natural().min(min, value);
max = Ordering.natural().max(max, value);
}
return closed(min, max);
}
}