001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the
010 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
011 * express or implied. See the License for the specific language governing permissions and
012 * limitations under the License.
013 */
014
015package com.google.common.collect;
016
017import com.google.common.annotations.Beta;
018
019import java.util.NoSuchElementException;
020import java.util.Set;
021
022import javax.annotation.Nullable;
023
024/**
025 * A set comprising zero or more {@linkplain Range#isEmpty nonempty}, 
026 * {@linkplain Range#isConnected(Range) disconnected} ranges of type {@code C}.
027 * 
028 * <p>Implementations that choose to support the {@link #add(Range)} operation are required to
029 * ignore empty ranges and coalesce connected ranges.  For example:  <pre>   {@code
030 *
031 *   RangeSet<Integer> rangeSet = TreeRangeSet.create();
032 *   rangeSet.add(Range.closed(1, 10)); // {[1, 10]}
033 *   rangeSet.add(Range.closedOpen(11, 15)); // {[1, 10], [11, 15)} 
034 *   rangeSet.add(Range.open(15, 20)); // disconnected range; {[1, 10], [11, 20)}
035 *   rangeSet.add(Range.openClosed(0, 0)); // empty range; {[1, 10], [11, 20)}
036 *   rangeSet.remove(Range.open(5, 10)); // splits [1, 10]; {[1, 5], [10, 10], [11, 20)}}</pre>
037 *   
038 * <p>Note that the behavior of {@link Range#isEmpty()} and {@link Range#isConnected(Range)} may
039 * not be as expected on discrete ranges.  See the Javadoc of those methods for details.
040 *
041 * <p>For a {@link Set} whose contents are specified by a {@link Range}, see {@link ContiguousSet}.
042 *
043 * @author Kevin Bourrillion
044 * @author Louis Wasserman
045 * @since 14.0
046 */
047@Beta
048public interface RangeSet<C extends Comparable> {
049  
050  // Query methods
051
052  /**
053   * Determines whether any of this range set's member ranges contains {@code value}.
054   */
055  boolean contains(C value);
056
057  /**
058   * Returns the unique range from this range set that {@linkplain Range#contains contains}
059   * {@code value}, or {@code null} if this range set does not contain {@code value}.
060   */
061  Range<C> rangeContaining(C value);
062
063  /**
064   * Returns {@code true} if there exists a member range in this range set which
065   * {@linkplain Range#encloses encloses} the specified range.
066   */
067  boolean encloses(Range<C> otherRange);
068
069  /**
070   * Returns {@code true} if for each member range in {@code other} there exists a member range in
071   * this range set which {@linkplain Range#encloses encloses} it. It follows that
072   * {@code this.contains(value)} whenever {@code other.contains(value)}. Returns {@code true} if
073   * {@code other} is empty.
074   *
075   * <p>This is equivalent to checking if this range set {@link #encloses} each of the ranges in
076   * {@code other}.
077   */
078  boolean enclosesAll(RangeSet<C> other);
079
080  /**
081   * Returns {@code true} if this range set contains no ranges.
082   */
083  boolean isEmpty();
084
085  /**
086   * Returns the minimal range which {@linkplain Range#encloses(Range) encloses} all ranges
087   * in this range set.
088   *
089   * @throws NoSuchElementException if this range set is {@linkplain #isEmpty() empty}
090   */
091  Range<C> span();
092
093  // Views
094  
095  /**
096   * Returns a view of the {@linkplain Range#isConnected disconnected} ranges that make up this
097   * range set.  The returned set may be empty. The iterators returned by its
098   * {@link Iterable#iterator} method return the ranges in increasing order of lower bound
099   * (equivalently, of upper bound).
100   */
101  Set<Range<C>> asRanges();
102
103  /**
104   * Returns a view of the complement of this {@code RangeSet}.
105   *
106   * <p>The returned view supports the {@link #add} operation if this {@code RangeSet} supports
107   * {@link #remove}, and vice versa.
108   */
109  RangeSet<C> complement();
110  
111  /**
112   * Returns a view of the intersection of this {@code RangeSet} with the specified range.
113   *
114   * <p>The returned view supports all optional operations supported by this {@code RangeSet}, with
115   * the caveat that an {@link IllegalArgumentException} is thrown on an attempt to
116   * {@linkplain #add(Range) add} any range not {@linkplain Range#encloses(Range) enclosed} by
117   * {@code view}.
118   */
119  RangeSet<C> subRangeSet(Range<C> view);
120  
121  // Modification
122
123  /**
124   * Adds the specified range to this {@code RangeSet} (optional operation). That is, for equal
125   * range sets a and b, the result of {@code a.add(range)} is that {@code a} will be the minimal
126   * range set for which both {@code a.enclosesAll(b)} and {@code a.encloses(range)}.
127   *
128   * <p>Note that {@code range} will be {@linkplain Range#span(Range) coalesced} with any ranges in
129   * the range set that are {@linkplain Range#isConnected(Range) connected} with it.  Moreover,
130   * if {@code range} is empty, this is a no-op.
131   *
132   * @throws UnsupportedOperationException if this range set does not support the {@code add}
133   *         operation
134   */
135  void add(Range<C> range);
136
137  /**
138   * Removes the specified range from this {@code RangeSet} (optional operation). After this
139   * operation, if {@code range.contains(c)}, {@code this.contains(c)} will return {@code false}.
140   *
141   * <p>If {@code range} is empty, this is a no-op.
142   *
143   * @throws UnsupportedOperationException if this range set does not support the {@code remove}
144   *         operation
145   */
146  void remove(Range<C> range);
147  
148  /**
149   * Removes all ranges from this {@code RangeSet} (optional operation).  After this operation,
150   * {@code this.contains(c)} will return false for all {@code c}.
151   * 
152   * <p>This is equivalent to {@code remove(Range.all())}.
153   * 
154   * @throws UnsupportedOperationException if this range set does not support the {@code clear}
155   *         operation
156   */
157  void clear();
158
159  /**
160   * Adds all of the ranges from the specified range set to this range set (optional operation).
161   * After this operation, this range set is the minimal range set that
162   * {@linkplain #enclosesAll(RangeSet) encloses} both the original range set and {@code other}.
163   *
164   * <p>This is equivalent to calling {@link #add} on each of the ranges in {@code other} in turn.
165   *
166   * @throws UnsupportedOperationException if this range set does not support the {@code addAll}
167   *         operation
168   */
169  void addAll(RangeSet<C> other);
170
171  /**
172   * Removes all of the ranges from the specified range set from this range set (optional
173   * operation). After this operation, if {@code other.contains(c)}, {@code this.contains(c)} will
174   * return {@code false}.
175   *
176   * <p>This is equivalent to calling {@link #remove} on each of the ranges in {@code other} in
177   * turn.
178   *
179   * @throws UnsupportedOperationException if this range set does not support the {@code removeAll}
180   *         operation
181   */
182  void removeAll(RangeSet<C> other);
183  
184  // Object methods
185
186  /**
187   * Returns {@code true} if {@code obj} is another {@code RangeSet} that contains the same ranges
188   * according to {@link Range#equals(Object)}.
189   */
190  @Override
191  boolean equals(@Nullable Object obj);
192  
193  /**
194   * Returns {@code asRanges().hashCode()}.
195   */
196  @Override
197  int hashCode();
198
199  /**
200   * Returns a readable string representation of this range set. For example, if this
201   * {@code RangeSet} consisted of {@code Range.closed(1, 3)} and {@code Range.greaterThan(4)},
202   * this might return {@code " [1‥3](4‥+∞)}"}.
203   */
204  @Override
205  String toString();
206}