https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
/*
 * Copyright (C) 2008 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.GwtCompatible;
import com.google.common.base.Equivalence;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import java.io.Serializable;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.SortedSet;
import org.checkerframework.checker.nullness.qual.Nullable;


A range (or "interval") defines the boundaries around a contiguous span of values of some Comparable type; for example, "integers from 1 to 100 inclusive." Note that it is not possible to iterate over these contained values. To do so, pass this range instance and an appropriate DiscreteDomain to ContiguousSet.create. 
Types of ranges


Each end of the range may be bounded or unbounded. If bounded, there is an associated
endpoint value, and the range is considered to be either open (does not include the
endpoint) or closed (includes the endpoint) on that side. With three possibilities on each side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket ([ ]) indicates that the range is closed on that side; a parenthesis (( )) means it is either open or unbounded. The construct {x | statement} is read "the set of all x such that statement.")




Range Types

Notation        Definition               Factory method

(a..b) {x | a < x < b} open 
[a..b] {x | a <= x <= b}closed 
(a..b] {x | a < x <= b} openClosed 
[a..b) {x | a <= x < b} closedOpen 
(a..+∞) {x | x > a} greaterThan 
[a..+∞) {x | x >= a} atLeast 
(-∞..b) {x | x < b} lessThan 
(-∞..b] {x | x <= b} atMost 
(-∞..+∞){x} all 




When both endpoints exist, the upper endpoint may not be less than the lower. The endpoints
may be equal only if at least one of the bounds is closed:

    
  
  • [a..a] : a singleton range 
  • [a..a); (a..a] : empty ranges; also valid 
  • (a..a) : invalid; an exception will be thrown



Warnings


    
  
  • Use immutable value types only, if at all possible. If you must use a mutable type, do
      not allow the endpoint instances to mutate after the range is created!
  
  • Your value type's comparison method should be consistent with
      equals if at all possible. Otherwise, be aware that concepts used throughout this documentation such as "equal", "same", "unique" and so on actually refer to whether compareTo returns zero, not whether equals returns true. 
  • A class which implements Comparable<UnrelatedType> is very broken, and will cause undefined horrible things to happen in Range. For now, the Range API does not prevent its use, because this would also rule out all ungenerified (pre-JDK1.5) data types. This may change in the future.



Other notes


    
  
  • Instances of this type are obtained using the static factory methods in this class.
  
  • Ranges are convex: whenever two values are contained, all values in between them must also be contained. More formally, for any c1 <= c2 <= c3 of type C, r.contains(c1) && r.contains(c3) implies r.contains(c2)). This means that a Range<Integer> can never be used to represent, say, "all prime numbers from
      1 to 100."
  
  • When evaluated as a Predicate, a range yields the same result as invoking contains. 
  • Terminology note: a range a is said to be the maximal range having property
      P if, for all ranges b also having property P, a.encloses(b). Likewise, a is minimal when b.encloses(a) for all b having property P. See, for example, the definition of intersection. 


Further reading


See the Guava User Guide article on Range.

Author:Kevin Bourrillion, Gregory Kick
Since:10.0
/**
 * A range (or "interval") defines the <i>boundaries</i> around a contiguous span of values of some
 * {@code Comparable} type; for example, "integers from 1 to 100 inclusive." Note that it is not
 * possible to <i>iterate</i> over these contained values. To do so, pass this range instance and an
 * appropriate {@link DiscreteDomain} to {@link ContiguousSet#create}.
 *
 * <h3>Types of ranges</h3>
 *
 * <p>Each end of the range may be bounded or unbounded. If bounded, there is an associated
 * <i>endpoint</i> value, and the range is considered to be either <i>open</i> (does not include the
 * endpoint) or <i>closed</i> (includes the endpoint) on that side. With three possibilities on each
 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means
 * it is either open or unbounded. The construct {@code {x | statement}} is read "the set of all
 * <i>x</i> such that <i>statement</i>.")
 *
 * <blockquote>
 *
 * <table>
 * <caption>Range Types</caption>
 * <tr><th>Notation        <th>Definition               <th>Factory method
 * <tr><td>{@code (a..b)}  <td>{@code {x | a < x < b}}  <td>{@link Range#open open}
 * <tr><td>{@code [a..b]}  <td>{@code {x | a <= x <= b}}<td>{@link Range#closed closed}
 * <tr><td>{@code (a..b]}  <td>{@code {x | a < x <= b}} <td>{@link Range#openClosed openClosed}
 * <tr><td>{@code [a..b)}  <td>{@code {x | a <= x < b}} <td>{@link Range#closedOpen closedOpen}
 * <tr><td>{@code (a..+∞)} <td>{@code {x | x > a}}      <td>{@link Range#greaterThan greaterThan}
 * <tr><td>{@code [a..+∞)} <td>{@code {x | x >= a}}     <td>{@link Range#atLeast atLeast}
 * <tr><td>{@code (-∞..b)} <td>{@code {x | x < b}}      <td>{@link Range#lessThan lessThan}
 * <tr><td>{@code (-∞..b]} <td>{@code {x | x <= b}}     <td>{@link Range#atMost atMost}
 * <tr><td>{@code (-∞..+∞)}<td>{@code {x}}              <td>{@link Range#all all}
 * </table>
 *
 * </blockquote>
 *
 * <p>When both endpoints exist, the upper endpoint may not be less than the lower. The endpoints
 * may be equal only if at least one of the bounds is closed:
 *
 * <ul>
 *   <li>{@code [a..a]} : a singleton range
 *   <li>{@code [a..a); (a..a]} : {@linkplain #isEmpty empty} ranges; also valid
 *   <li>{@code (a..a)} : <b>invalid</b>; an exception will be thrown
 * </ul>
 *
 * <h3>Warnings</h3>
 *
 * <ul>
 *   <li>Use immutable value types only, if at all possible. If you must use a mutable type, <b>do
 *       not</b> allow the endpoint instances to mutate after the range is created!
 *   <li>Your value type's comparison method should be {@linkplain Comparable consistent with
 *       equals} if at all possible. Otherwise, be aware that concepts used throughout this
 *       documentation such as "equal", "same", "unique" and so on actually refer to whether {@link
 *       Comparable#compareTo compareTo} returns zero, not whether {@link Object#equals equals}
 *       returns {@code true}.
 *   <li>A class which implements {@code Comparable<UnrelatedType>} is very broken, and will cause
 *       undefined horrible things to happen in {@code Range}. For now, the Range API does not
 *       prevent its use, because this would also rule out all ungenerified (pre-JDK1.5) data types.
 *       <b>This may change in the future.</b>
 * </ul>
 *
 * <h3>Other notes</h3>
 *
 * <ul>
 *   <li>Instances of this type are obtained using the static factory methods in this class.
 *   <li>Ranges are <i>convex</i>: whenever two values are contained, all values in between them
 *       must also be contained. More formally, for any {@code c1 <= c2 <= c3} of type {@code C},
 *       {@code r.contains(c1) && r.contains(c3)} implies {@code r.contains(c2)}). This means that a
 *       {@code Range<Integer>} can never be used to represent, say, "all <i>prime</i> numbers from
 *       1 to 100."
 *   <li>When evaluated as a {@link Predicate}, a range yields the same result as invoking {@link
 *       #contains}.
 *   <li>Terminology note: a range {@code a} is said to be the <i>maximal</i> range having property
 *       <i>P</i> if, for all ranges {@code b} also having property <i>P</i>, {@code a.encloses(b)}.
 *       Likewise, {@code a} is <i>minimal</i> when {@code b.encloses(a)} for all {@code b} having
 *       property <i>P</i>. See, for example, the definition of {@link #intersection intersection}.
 * </ul>
 *
 * <h3>Further reading</h3>
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/RangesExplained">{@code Range}</a>.
 *
 * @author Kevin Bourrillion
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@SuppressWarnings("rawtypes")
public final class Range<C extends Comparable> extends RangeGwtSerializationDependencies
    implements Predicate<C>, Serializable {

  static class LowerBoundFn implements Function<Range, Cut> {
    static final LowerBoundFn INSTANCE = new LowerBoundFn();

    @Override
    public Cut apply(Range range) {
      return range.lowerBound;
    }
  }

  static class UpperBoundFn implements Function<Range, Cut> {
    static final UpperBoundFn INSTANCE = new UpperBoundFn();

    @Override
    public Cut apply(Range range) {
      return range.upperBound;
    }
  }

  @SuppressWarnings("unchecked")
  static <C extends Comparable<?>> Function<Range<C>, Cut<C>> lowerBoundFn() {
    return (Function) LowerBoundFn.INSTANCE;
  }

  @SuppressWarnings("unchecked")
  static <C extends Comparable<?>> Function<Range<C>, Cut<C>> upperBoundFn() {
    return (Function) UpperBoundFn.INSTANCE;
  }

  static <C extends Comparable<?>> Ordering<Range<C>> rangeLexOrdering() {
    return (Ordering<Range<C>>) (Ordering) RangeLexOrdering.INSTANCE;
  }

  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 lower and strictly less than upper. 
Throws:
Since:14.0
/**
   * 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}
   * @throws ClassCastException if {@code lower} and {@code upper} are not mutually comparable
   * @since 14.0
   */
  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 lower and less than or equal to upper. 
Throws:
Since:14.0
/**
   * 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}
   * @throws ClassCastException if {@code lower} and {@code upper} are not mutually comparable
   * @since 14.0
   */
  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 lower and strictly less than upper. 
Throws:
Since:14.0
/**
   * 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}
   * @throws ClassCastException if {@code lower} and {@code upper} are not mutually comparable
   * @since 14.0
   */
  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 lower and less than or equal to upper. 
Throws:
Since:14.0
/**
   * 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}
   * @throws ClassCastException if {@code lower} and {@code upper} are not mutually comparable
   * @since 14.0
   */
  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 lower to upper, where each endpoint may be either inclusive (closed) or exclusive (open). 
Throws:
Since:14.0
/**
   * 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}
   * @throws ClassCastException if {@code lower} and {@code upper} are not mutually comparable
   * @since 14.0
   */
  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 endpoint. 
Since:14.0
/**
   * Returns a range that contains all values strictly less than {@code endpoint}.
   *
   * @since 14.0
   */
  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 endpoint. 
Since:14.0
/**
   * Returns a range that contains all values less than or equal to {@code endpoint}.
   *
   * @since 14.0
   */
  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).

Since:14.0
/**
   * Returns a range with no lower bound up to the given endpoint, which may be either inclusive
   * (closed) or exclusive (open).
   *
   * @since 14.0
   */
  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 endpoint. 
Since:14.0
/**
   * Returns a range that contains all values strictly greater than {@code endpoint}.
   *
   * @since 14.0
   */
  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 endpoint. 
Since:14.0
/**
   * Returns a range that contains all values greater than or equal to {@code endpoint}.
   *
   * @since 14.0
   */
  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.

Since:14.0
/**
   * Returns a range from the given endpoint, which may be either inclusive (closed) or exclusive
   * (open), with no upper bound.
   *
   * @since 14.0
   */
  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();
    }
  }

  private static final Range<Comparable> ALL = new Range<>(Cut.belowAll(), Cut.aboveAll());

  
Returns a range that contains every value of type C. 
Since:14.0
/**
   * Returns a range that contains every value of type {@code C}.
   *
   * @since 14.0
   */
  @SuppressWarnings("unchecked")
  public static <C extends Comparable<?>> Range<C> all() {
    return (Range) ALL;
  }

  
Returns a range that contains only the given value. The returned range is closed on both ends. 
Since:14.0
/**
   * Returns a range that {@linkplain Range#contains(Comparable) contains} only the given value. The
   * returned range is {@linkplain BoundType#CLOSED closed} on both ends.
   *
   * @since 14.0
   */
  public static <C extends Comparable<?>> Range<C> singleton(C value) {
    return closed(value, value);
  }

  
Returns the minimal range that contains all of the given values. The returned range is closed on both ends. 
Throws:
Since:14.0
/**
   * 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 values are not mutually comparable
   * @throws NoSuchElementException if {@code values} is empty
   * @throws NullPointerException if any of {@code values} is null
   * @since 14.0
   */
  public static <C extends Comparable<?>> Range<C> encloseAll(Iterable<C> values) {
    checkNotNull(values);
    if (values instanceof SortedSet) {
      SortedSet<? extends C> set = cast(values);
      Comparator<?> comparator = set.comparator();
      if (Ordering.natural().equals(comparator) || comparator == null) {
        return closed(set.first(), set.last());
      }
    }
    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);
  }

  final Cut<C> lowerBound;
  final Cut<C> upperBound;

  private Range(Cut<C> lowerBound, Cut<C> upperBound) {
    this.lowerBound = checkNotNull(lowerBound);
    this.upperBound = checkNotNull(upperBound);
    if (lowerBound.compareTo(upperBound) > 0
        || lowerBound == Cut.<C>aboveAll()
        || upperBound == Cut.<C>belowAll()) {
      throw new IllegalArgumentException("Invalid range: " + toString(lowerBound, upperBound));
    }
  }

  
Returns true if this range has a lower endpoint. 
/** Returns {@code true} if this range has a lower endpoint. */
  public boolean hasLowerBound() {
    return lowerBound != Cut.belowAll();
  }

  
Returns the lower endpoint of this range.

Throws:
  • IllegalStateException – if this range is unbounded below (that is, hasLowerBound() returns false)
/**
   * Returns the lower endpoint of this range.
   *
   * @throws IllegalStateException if this range is unbounded below (that is, {@link
   *     #hasLowerBound()} returns {@code false})
   */
  public C lowerEndpoint() {
    return lowerBound.endpoint();
  }

  
Returns the type of this range's lower bound: BoundType.CLOSED if the range includes its lower endpoint, BoundType.OPEN if it does not. 
Throws:
/**
   * Returns the type of this range's lower bound: {@link BoundType#CLOSED} if the range includes
   * its lower endpoint, {@link BoundType#OPEN} if it does not.
   *
   * @throws IllegalStateException if this range is unbounded below (that is, {@link
   *     #hasLowerBound()} returns {@code false})
   */
  public BoundType lowerBoundType() {
    return lowerBound.typeAsLowerBound();
  }

  
Returns true if this range has an upper endpoint. 
/** Returns {@code true} if this range has an upper endpoint. */
  public boolean hasUpperBound() {
    return upperBound != Cut.aboveAll();
  }

  
Returns the upper endpoint of this range.

Throws:
  • IllegalStateException – if this range is unbounded above (that is, hasUpperBound() returns false)
/**
   * Returns the upper endpoint of this range.
   *
   * @throws IllegalStateException if this range is unbounded above (that is, {@link
   *     #hasUpperBound()} returns {@code false})
   */
  public C upperEndpoint() {
    return upperBound.endpoint();
  }

  
Returns the type of this range's upper bound: BoundType.CLOSED if the range includes its upper endpoint, BoundType.OPEN if it does not. 
Throws:
/**
   * Returns the type of this range's upper bound: {@link BoundType#CLOSED} if the range includes
   * its upper endpoint, {@link BoundType#OPEN} if it does not.
   *
   * @throws IllegalStateException if this range is unbounded above (that is, {@link
   *     #hasUpperBound()} returns {@code false})
   */
  public BoundType upperBoundType() {
    return upperBound.typeAsUpperBound();
  }

  
Returns true if this range is of the form [v..v) or (v..v]. (This does not encompass ranges of the form (v..v), because such ranges are invalid and
can't be constructed at all.)

Note that certain discrete ranges such as the integer range (3..4) are not considered empty, even though they contain no actual values. In these cases, it may be helpful to preprocess ranges with canonical(DiscreteDomain). 
/**
   * Returns {@code true} if this range is of the form {@code [v..v)} or {@code (v..v]}. (This does
   * not encompass ranges of the form {@code (v..v)}, because such ranges are <i>invalid</i> and
   * can't be constructed at all.)
   *
   * <p>Note that certain discrete ranges such as the integer range {@code (3..4)} are <b>not</b>
   * considered empty, even though they contain no actual values. In these cases, it may be helpful
   * to preprocess ranges with {@link #canonical(DiscreteDomain)}.
   */
  public boolean isEmpty() {
    return lowerBound.equals(upperBound);
  }

  
Returns true if value is within the bounds of this range. For example, on the range [0..2), contains(1) returns true, while contains(2) returns false. 
/**
   * Returns {@code true} if {@code value} is within the bounds of this range. For example, on the
   * range {@code [0..2)}, {@code contains(1)} returns {@code true}, while {@code contains(2)}
   * returns {@code false}.
   */
  public boolean contains(C value) {
    checkNotNull(value);
    // let this throw CCE if there is some trickery going on
    return lowerBound.isLessThan(value) && !upperBound.isLessThan(value);
  }

  
Deprecated:Provided only to satisfy the Predicate interface; use contains instead.
/**
   * @deprecated Provided only to satisfy the {@link Predicate} interface; use {@link #contains}
   *     instead.
   */
  @Deprecated
  @Override
  public boolean apply(C input) {
    return contains(input);
  }

  
Returns true if every element in values is contained in this range. 
/**
   * Returns {@code true} if every element in {@code values} is {@linkplain #contains contained} in
   * this range.
   */
  public boolean containsAll(Iterable<? extends C> values) {
    if (Iterables.isEmpty(values)) {
      return true;
    }

    // this optimizes testing equality of two range-backed sets
    if (values instanceof SortedSet) {
      SortedSet<? extends C> set = cast(values);
      Comparator<?> comparator = set.comparator();
      if (Ordering.natural().equals(comparator) || comparator == null) {
        return contains(set.first()) && contains(set.last());
      }
    }

    for (C value : values) {
      if (!contains(value)) {
        return false;
      }
    }
    return true;
  }

  
Returns true if the bounds of other do not extend outside the bounds of this range. Examples: 
    
  
  • [3..6] encloses [4..5] 
  • (3..6) encloses (3..6) 
  • [3..6] encloses [4..4) (even though the latter is empty) 
  • (3..6] does not enclose [3..6] 
  • [4..5] does not enclose (3..6) (even though it contains every value contained by the latter range) 
  • [3..6] does not enclose (1..1] (even though it contains every value contained by the latter range) 


Note that if a.encloses(b), then b.contains(v) implies 
a.contains(v), but as the last two examples illustrate, the converse is not always true. 
Being reflexive, antisymmetric and transitive, the encloses relation defines a partial order over ranges. There exists a unique maximal range according to this relation, and also numerous minimal ranges. Enclosure also implies connectedness. 
/**
   * Returns {@code true} if the bounds of {@code other} do not extend outside the bounds of this
   * range. Examples:
   *
   * <ul>
   *   <li>{@code [3..6]} encloses {@code [4..5]}
   *   <li>{@code (3..6)} encloses {@code (3..6)}
   *   <li>{@code [3..6]} encloses {@code [4..4)} (even though the latter is empty)
   *   <li>{@code (3..6]} does not enclose {@code [3..6]}
   *   <li>{@code [4..5]} does not enclose {@code (3..6)} (even though it contains every value
   *       contained by the latter range)
   *   <li>{@code [3..6]} does not enclose {@code (1..1]} (even though it contains every value
   *       contained by the latter range)
   * </ul>
   *
   * <p>Note that if {@code a.encloses(b)}, then {@code b.contains(v)} implies {@code
   * a.contains(v)}, but as the last two examples illustrate, the converse is not always true.
   *
   * <p>Being reflexive, antisymmetric and transitive, the {@code encloses} relation defines a
   * <i>partial order</i> over ranges. There exists a unique {@linkplain Range#all maximal} range
   * according to this relation, and also numerous {@linkplain #isEmpty minimal} ranges. Enclosure
   * also implies {@linkplain #isConnected connectedness}.
   */
  public boolean encloses(Range<C> other) {
    return lowerBound.compareTo(other.lowerBound) <= 0
        && upperBound.compareTo(other.upperBound) >= 0;
  }

  
Returns true if there exists a (possibly empty) range which is 
enclosed by both this range and other. 
For example,

    
  
  • [2, 4) and [5, 7) are not connected 
  • [2, 4) and [3, 5) are connected, because both enclose [3, 4) 
  • [2, 4) and [4, 6) are connected, because both enclose the empty range [4, 4) 


Note that this range and other have a well-defined union and intersection (as a single, possibly-empty range) if and only if this method returns true. 
The connectedness relation is both reflexive and symmetric, but does not form an equivalence relation as it is not transitive. 
Note that certain discrete ranges are not considered connected, even though there are no elements "between them." For example, [3, 5] is not considered connected to [6,
10]. In these cases, it may be desirable for both input ranges to be preprocessed with canonical(DiscreteDomain) before testing for connectedness. 
/**
   * Returns {@code true} if there exists a (possibly empty) range which is {@linkplain #encloses
   * enclosed} by both this range and {@code other}.
   *
   * <p>For example,
   *
   * <ul>
   *   <li>{@code [2, 4)} and {@code [5, 7)} are not connected
   *   <li>{@code [2, 4)} and {@code [3, 5)} are connected, because both enclose {@code [3, 4)}
   *   <li>{@code [2, 4)} and {@code [4, 6)} are connected, because both enclose the empty range
   *       {@code [4, 4)}
   * </ul>
   *
   * <p>Note that this range and {@code other} have a well-defined {@linkplain #span union} and
   * {@linkplain #intersection intersection} (as a single, possibly-empty range) if and only if this
   * method returns {@code true}.
   *
   * <p>The connectedness relation is both reflexive and symmetric, but does not form an {@linkplain
   * Equivalence equivalence relation} as it is not transitive.
   *
   * <p>Note that certain discrete ranges are not considered connected, even though there are no
   * elements "between them." For example, {@code [3, 5]} is not considered connected to {@code [6,
   * 10]}. In these cases, it may be desirable for both input ranges to be preprocessed with {@link
   * #canonical(DiscreteDomain)} before testing for connectedness.
   */
  public boolean isConnected(Range<C> other) {
    return lowerBound.compareTo(other.upperBound) <= 0
        && other.lowerBound.compareTo(upperBound) <= 0;
  }

  
Returns the maximal range enclosed by both this range and 
connectedRange, if such a range exists. 
For example, the intersection of [1..5] and (3..7) is (3..5]. The resulting range may be empty; for example, [1..5) intersected with [5..7) yields the empty range [5..5). 
The intersection exists if and only if the two ranges are 
connected. 
The intersection operation is commutative, associative and idempotent, and its identity element is all). 
Throws:
/**
   * Returns the maximal range {@linkplain #encloses enclosed} by both this range and {@code
   * connectedRange}, if such a range exists.
   *
   * <p>For example, the intersection of {@code [1..5]} and {@code (3..7)} is {@code (3..5]}. The
   * resulting range may be empty; for example, {@code [1..5)} intersected with {@code [5..7)}
   * yields the empty range {@code [5..5)}.
   *
   * <p>The intersection exists if and only if the two ranges are {@linkplain #isConnected
   * connected}.
   *
   * <p>The intersection operation is commutative, associative and idempotent, and its identity
   * element is {@link Range#all}).
   *
   * @throws IllegalArgumentException if {@code isConnected(connectedRange)} is {@code false}
   */
  public Range<C> intersection(Range<C> connectedRange) {
    int lowerCmp = lowerBound.compareTo(connectedRange.lowerBound);
    int upperCmp = upperBound.compareTo(connectedRange.upperBound);
    if (lowerCmp >= 0 && upperCmp <= 0) {
      return this;
    } else if (lowerCmp <= 0 && upperCmp >= 0) {
      return connectedRange;
    } else {
      Cut<C> newLower = (lowerCmp >= 0) ? lowerBound : connectedRange.lowerBound;
      Cut<C> newUpper = (upperCmp <= 0) ? upperBound : connectedRange.upperBound;
      return create(newLower, newUpper);
    }
  }

  
Returns the maximal range lying between this range and otherRange, if such a range exists. The resulting range may be empty if the two ranges are adjacent but non-overlapping. 
For example, the gap of [1..5] and (7..10) is (5..7]. The resulting range may be empty; for example, the gap between [1..5) [5..7) yields the empty range [5..5). 
The gap exists if and only if the two ranges are either disconnected or immediately adjacent
(any intersection must be an empty range).

The gap operation is commutative.

Throws:
Since:27.0
/**
   * Returns the maximal range lying between this range and {@code otherRange}, if such a range
   * exists. The resulting range may be empty if the two ranges are adjacent but non-overlapping.
   *
   * <p>For example, the gap of {@code [1..5]} and {@code (7..10)} is {@code (5..7]}. The resulting
   * range may be empty; for example, the gap between {@code [1..5)} {@code [5..7)} yields the empty
   * range {@code [5..5)}.
   *
   * <p>The gap exists if and only if the two ranges are either disconnected or immediately adjacent
   * (any intersection must be an empty range).
   *
   * <p>The gap operation is commutative.
   *
   * @throws IllegalArgumentException if this range and {@code otherRange} have a nonempty
   *     intersection
   * @since 27.0
   */
  public Range<C> gap(Range<C> otherRange) {
    boolean isThisFirst = this.lowerBound.compareTo(otherRange.lowerBound) < 0;
    Range<C> firstRange = isThisFirst ? this : otherRange;
    Range<C> secondRange = isThisFirst ? otherRange : this;
    return create(firstRange.upperBound, secondRange.lowerBound);
  }

  
Returns the minimal range that encloses both this range and 
other. For example, the span of [1..3] and (5..7) is [1..7). 
If the input ranges are connected, the returned range can also be called their union. If they are not, note that the span might contain values
that are not contained in either input range.

Like intersection, this operation is commutative, associative and idempotent. Unlike it, it is always well-defined for any two input ranges. 
/**
   * Returns the minimal range that {@linkplain #encloses encloses} both this range and {@code
   * other}. For example, the span of {@code [1..3]} and {@code (5..7)} is {@code [1..7)}.
   *
   * <p><i>If</i> the input ranges are {@linkplain #isConnected connected}, the returned range can
   * also be called their <i>union</i>. If they are not, note that the span might contain values
   * that are not contained in either input range.
   *
   * <p>Like {@link #intersection(Range) intersection}, this operation is commutative, associative
   * and idempotent. Unlike it, it is always well-defined for any two input ranges.
   */
  public Range<C> span(Range<C> other) {
    int lowerCmp = lowerBound.compareTo(other.lowerBound);
    int upperCmp = upperBound.compareTo(other.upperBound);
    if (lowerCmp <= 0 && upperCmp >= 0) {
      return this;
    } else if (lowerCmp >= 0 && upperCmp <= 0) {
      return other;
    } else {
      Cut<C> newLower = (lowerCmp <= 0) ? lowerBound : other.lowerBound;
      Cut<C> newUpper = (upperCmp >= 0) ? upperBound : other.upperBound;
      return create(newLower, newUpper);
    }
  }

  
Returns the canonical form of this range in the given domain. The canonical form has the
following properties:

    
  
  • equivalence: a.canonical().contains(v) == a.contains(v) for all v (in other words, ContiguousSet.create(a.canonical(domain), domain).equals(
      ContiguousSet.create(a, domain)) 
  • uniqueness: unless a.isEmpty(), ContiguousSet.create(a,
      domain).equals(ContiguousSet.create(b, domain)) implies 
      a.canonical(domain).equals(b.canonical(domain)) 
  • idempotence: a.canonical(domain).canonical(domain).equals(a.canonical(domain)) 


Furthermore, this method guarantees that the range returned will be one of the following
canonical forms:

    
  
  • [start..end)
  
  • [start..+∞)
  
  • (-∞..end) (only if type C is unbounded below) 
  • (-∞..+∞) (only if type C is unbounded below) 


/**
   * Returns the canonical form of this range in the given domain. The canonical form has the
   * following properties:
   *
   * <ul>
   *   <li>equivalence: {@code a.canonical().contains(v) == a.contains(v)} for all {@code v} (in
   *       other words, {@code ContiguousSet.create(a.canonical(domain), domain).equals(
   *       ContiguousSet.create(a, domain))}
   *   <li>uniqueness: unless {@code a.isEmpty()}, {@code ContiguousSet.create(a,
   *       domain).equals(ContiguousSet.create(b, domain))} implies {@code
   *       a.canonical(domain).equals(b.canonical(domain))}
   *   <li>idempotence: {@code a.canonical(domain).canonical(domain).equals(a.canonical(domain))}
   * </ul>
   *
   * <p>Furthermore, this method guarantees that the range returned will be one of the following
   * canonical forms:
   *
   * <ul>
   *   <li>[start..end)
   *   <li>[start..+∞)
   *   <li>(-∞..end) (only if type {@code C} is unbounded below)
   *   <li>(-∞..+∞) (only if type {@code C} is unbounded below)
   * </ul>
   */
  public Range<C> canonical(DiscreteDomain<C> domain) {
    checkNotNull(domain);
    Cut<C> lower = lowerBound.canonical(domain);
    Cut<C> upper = upperBound.canonical(domain);
    return (lower == lowerBound && upper == upperBound) ? this : create(lower, upper);
  }

  
Returns true if object is a range having the same endpoints and bound types as this range. Note that discrete ranges such as (1..4) and [2..3] are not equal to one another, despite the fact that they each contain precisely the same set of values. Similarly, empty ranges are not equal unless they have exactly the same representation, so [3..3), (3..3], (4..4] are all unequal. 
/**
   * Returns {@code true} if {@code object} is a range having the same endpoints and bound types as
   * this range. Note that discrete ranges such as {@code (1..4)} and {@code [2..3]} are <b>not</b>
   * equal to one another, despite the fact that they each contain precisely the same set of values.
   * Similarly, empty ranges are not equal unless they have exactly the same representation, so
   * {@code [3..3)}, {@code (3..3]}, {@code (4..4]} are all unequal.
   */
  @Override
  public boolean equals(@Nullable Object object) {
    if (object instanceof Range) {
      Range<?> other = (Range<?>) object;
      return lowerBound.equals(other.lowerBound) && upperBound.equals(other.upperBound);
    }
    return false;
  }

  
Returns a hash code for this range. 
/** Returns a hash code for this range. */
  @Override
  public int hashCode() {
    return lowerBound.hashCode() * 31 + upperBound.hashCode();
  }

  
Returns a string representation of this range, such as "[3..5)" (other examples are listed in the class documentation). 
/**
   * Returns a string representation of this range, such as {@code "[3..5)"} (other examples are
   * listed in the class documentation).
   */
  @Override
  public String toString() {
    return toString(lowerBound, upperBound);
  }

  private static String toString(Cut<?> lowerBound, Cut<?> upperBound) {
    StringBuilder sb = new StringBuilder(16);
    lowerBound.describeAsLowerBound(sb);
    sb.append("..");
    upperBound.describeAsUpperBound(sb);
    return sb.toString();
  }

  
Used to avoid http://bugs.sun.com/view_bug.do?bug_id=6558557 
/** Used to avoid http://bugs.sun.com/view_bug.do?bug_id=6558557 */
  private static <T> SortedSet<T> cast(Iterable<T> iterable) {
    return (SortedSet<T>) iterable;
  }

  Object readResolve() {
    if (this.equals(ALL)) {
      return all();
    } else {
      return this;
    }
  }

  @SuppressWarnings("unchecked") // this method may throw CCE
  static int compareOrThrow(Comparable left, Comparable right) {
    return left.compareTo(right);
  }

  
Needed to serialize sorted collections of Ranges. 
/** Needed to serialize sorted collections of Ranges. */
  private static class RangeLexOrdering extends Ordering<Range<?>> implements Serializable {
    static final Ordering<Range<?>> INSTANCE = new RangeLexOrdering();

    @Override
    public int compare(Range<?> left, Range<?> right) {
      return ComparisonChain.start()
          .compare(left.lowerBound, right.lowerBound)
          .compare(left.upperBound, right.upperBound)
          .result();
    }

    private static final long serialVersionUID = 0;
  }

  private static final long serialVersionUID = 0;
}