1/* 2 * Copyright (C) 2010 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14 15package com.google.common.collect; 16 17import static com.google.common.base.Preconditions.checkArgument; 18import static com.google.common.base.Preconditions.checkNotNull; 19 20import com.google.common.annotations.Beta; 21import com.google.common.annotations.GwtCompatible; 22 23import java.util.NoSuchElementException; 24 25/** 26 * A sorted set of contiguous values in a given {@link DiscreteDomain}. 27 * 28 * <p><b>Warning:</b> Be extremely careful what you do with conceptually large instances (such as 29 * {@code ContiguousSet.create(Range.greaterThan(0), DiscreteDomain.integers()}). Certain 30 * operations on such a set can be performed efficiently, but others (such as {@link Set#hashCode} 31 * or {@link Collections#frequency}) can cause major performance problems. 32 * 33 * @author Gregory Kick 34 * @since 10.0 35 */ 36@Beta 37@GwtCompatible(emulated = true) 38@SuppressWarnings("rawtypes") // allow ungenerified Comparable types 39public abstract class ContiguousSet<C extends Comparable> extends ImmutableSortedSet<C> { 40 /** 41 * Returns a {@code ContiguousSet} containing the same values in the given domain 42 * {@linkplain Range#contains contained} by the range. 43 * 44 * @throws IllegalArgumentException if neither range nor the domain has a lower bound, or if 45 * neither has an upper bound 46 * 47 * @since 13.0 48 */ 49 public static <C extends Comparable> ContiguousSet<C> create( 50 Range<C> range, DiscreteDomain<C> domain) { 51 checkNotNull(range); 52 checkNotNull(domain); 53 Range<C> effectiveRange = range; 54 try { 55 if (!range.hasLowerBound()) { 56 effectiveRange = effectiveRange.intersection(Range.atLeast(domain.minValue())); 57 } 58 if (!range.hasUpperBound()) { 59 effectiveRange = effectiveRange.intersection(Range.atMost(domain.maxValue())); 60 } 61 } catch (NoSuchElementException e) { 62 throw new IllegalArgumentException(e); 63 } 64 65 // Per class spec, we are allowed to throw CCE if necessary 66 boolean empty = effectiveRange.isEmpty() 67 || Range.compareOrThrow( 68 range.lowerBound.leastValueAbove(domain), 69 range.upperBound.greatestValueBelow(domain)) > 0; 70 71 return empty 72 ? new EmptyContiguousSet<C>(domain) 73 : new RegularContiguousSet<C>(effectiveRange, domain); 74 } 75 76 final DiscreteDomain<C> domain; 77 78 ContiguousSet(DiscreteDomain<C> domain) { 79 super(Ordering.natural()); 80 this.domain = domain; 81 } 82 83 @Override public ContiguousSet<C> headSet(C toElement) { 84 return headSetImpl(checkNotNull(toElement), false); 85 } 86 87 @Override public ContiguousSet<C> subSet(C fromElement, C toElement) { 88 checkNotNull(fromElement); 89 checkNotNull(toElement); 90 checkArgument(comparator().compare(fromElement, toElement) <= 0); 91 return subSetImpl(fromElement, true, toElement, false); 92 } 93 94 @Override public ContiguousSet<C> tailSet(C fromElement) { 95 return tailSetImpl(checkNotNull(fromElement), true); 96 } 97 98 /* 99 * These methods perform most headSet, subSet, and tailSet logic, besides parameter validation. 100 */ 101 /*@Override*/ abstract ContiguousSet<C> headSetImpl(C toElement, boolean inclusive); 102 103 /*@Override*/ abstract ContiguousSet<C> subSetImpl(C fromElement, boolean fromInclusive, 104 C toElement, boolean toInclusive); 105 106 /*@Override*/ abstract ContiguousSet<C> tailSetImpl(C fromElement, boolean inclusive); 107 108 /** 109 * Returns the set of values that are contained in both this set and the other. 110 * 111 * <p>This method should always be used instead of 112 * {@link Sets#intersection} for {@link ContiguousSet} instances. 113 */ 114 public abstract ContiguousSet<C> intersection(ContiguousSet<C> other); 115 116 /** 117 * Returns a range, closed on both ends, whose endpoints are the minimum and maximum values 118 * contained in this set. This is equivalent to {@code range(CLOSED, CLOSED)}. 119 * 120 * @throws NoSuchElementException if this set is empty 121 */ 122 public abstract Range<C> range(); 123 124 /** 125 * Returns the minimal range with the given boundary types for which all values in this set are 126 * {@linkplain Range#contains(Comparable) contained} within the range. 127 * 128 * <p>Note that this method will return ranges with unbounded endpoints if {@link BoundType#OPEN} 129 * is requested for a domain minimum or maximum. For example, if {@code set} was created from the 130 * range {@code [1..Integer.MAX_VALUE]} then {@code set.range(CLOSED, OPEN)} must return 131 * {@code [1..∞)}. 132 * 133 * @throws NoSuchElementException if this set is empty 134 */ 135 public abstract Range<C> range(BoundType lowerBoundType, BoundType upperBoundType); 136 137 /** Returns a short-hand representation of the contents such as {@code "[1..100]"}. */ 138 @Override public String toString() { 139 return range().toString(); 140 } 141 142 /** 143 * Not supported. {@code ContiguousSet} instances are constructed with {@link #create}. This 144 * method exists only to hide {@link ImmutableSet#builder} from consumers of {@code 145 * ContiguousSet}. 146 * 147 * @throws UnsupportedOperationException always 148 * @deprecated Use {@link #create}. 149 */ 150 @Deprecated public static <E> ImmutableSortedSet.Builder<E> builder() { 151 throw new UnsupportedOperationException(); 152 } 153} 154 155