Java tutorial
/* * Copyright (C) 2012 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.checkElementIndex; import static com.google.common.base.Preconditions.checkNotNull; import com.google.common.annotations.Beta; import com.google.common.annotations.GwtIncompatible; import com.google.common.collect.SortedLists.KeyAbsentBehavior; import com.google.common.collect.SortedLists.KeyPresentBehavior; import java.io.Serializable; import java.util.Map; import java.util.Map.Entry; import java.util.NoSuchElementException; import javax.annotation.Nullable; /** * A {@link RangeMap} whose contents will never change, with many other important properties * detailed at {@link ImmutableCollection}. * * @author Louis Wasserman * @since 14.0 */ @Beta @GwtIncompatible("NavigableMap") public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K, V>, Serializable { private static final ImmutableRangeMap<Comparable<?>, Object> EMPTY = new ImmutableRangeMap<Comparable<?>, Object>( ImmutableList.<Range<Comparable<?>>>of(), ImmutableList.of()); /** * Returns an empty immutable range map. */ @SuppressWarnings("unchecked") public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() { return (ImmutableRangeMap<K, V>) EMPTY; } /** * Returns an immutable range map mapping a single range to a single value. */ public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of(Range<K> range, V value) { return new ImmutableRangeMap<K, V>(ImmutableList.of(range), ImmutableList.of(value)); } @SuppressWarnings("unchecked") public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> copyOf(RangeMap<K, ? extends V> rangeMap) { if (rangeMap instanceof ImmutableRangeMap) { return (ImmutableRangeMap<K, V>) rangeMap; } Map<Range<K>, ? extends V> map = rangeMap.asMapOfRanges(); ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<Range<K>>(map.size()); ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(map.size()); for (Entry<Range<K>, ? extends V> entry : map.entrySet()) { rangesBuilder.add(entry.getKey()); valuesBuilder.add(entry.getValue()); } return new ImmutableRangeMap<K, V>(rangesBuilder.build(), valuesBuilder.build()); } /** * Returns a new builder for an immutable range map. */ public static <K extends Comparable<?>, V> Builder<K, V> builder() { return new Builder<K, V>(); } /** * A builder for immutable range maps. Overlapping ranges are prohibited. */ public static final class Builder<K extends Comparable<?>, V> { private final RangeSet<K> keyRanges; private final RangeMap<K, V> rangeMap; public Builder() { this.keyRanges = TreeRangeSet.create(); this.rangeMap = TreeRangeMap.create(); } /** * Associates the specified range with the specified value. * * @throws IllegalArgumentException if {@code range} overlaps with any other ranges inserted * into this builder, or if {@code range} is empty */ public Builder<K, V> put(Range<K> range, V value) { checkNotNull(range); checkNotNull(value); checkArgument(!range.isEmpty(), "Range must not be empty, but was %s", range); if (!keyRanges.complement().encloses(range)) { // it's an error case; we can afford an expensive lookup for (Entry<Range<K>, V> entry : rangeMap.asMapOfRanges().entrySet()) { Range<K> key = entry.getKey(); if (key.isConnected(range) && !key.intersection(range).isEmpty()) { throw new IllegalArgumentException( "Overlapping ranges: range " + range + " overlaps with entry " + entry); } } } keyRanges.add(range); rangeMap.put(range, value); return this; } /** * Copies all associations from the specified range map into this builder. * * @throws IllegalArgumentException if any of the ranges in {@code rangeMap} overlap with ranges * already in this builder */ public Builder<K, V> putAll(RangeMap<K, ? extends V> rangeMap) { for (Entry<Range<K>, ? extends V> entry : rangeMap.asMapOfRanges().entrySet()) { put(entry.getKey(), entry.getValue()); } return this; } /** * Returns an {@code ImmutableRangeMap} containing the associations previously added to this * builder. */ public ImmutableRangeMap<K, V> build() { Map<Range<K>, V> map = rangeMap.asMapOfRanges(); ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<Range<K>>(map.size()); ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(map.size()); for (Entry<Range<K>, V> entry : map.entrySet()) { rangesBuilder.add(entry.getKey()); valuesBuilder.add(entry.getValue()); } return new ImmutableRangeMap<K, V>(rangesBuilder.build(), valuesBuilder.build()); } } private final transient ImmutableList<Range<K>> ranges; private final transient ImmutableList<V> values; ImmutableRangeMap(ImmutableList<Range<K>> ranges, ImmutableList<V> values) { this.ranges = ranges; this.values = values; } @Override @Nullable public V get(K key) { int index = SortedLists.binarySearch(ranges, Range.<K>lowerBoundFn(), Cut.belowValue(key), KeyPresentBehavior.ANY_PRESENT, KeyAbsentBehavior.NEXT_LOWER); if (index == -1) { return null; } else { Range<K> range = ranges.get(index); return range.contains(key) ? values.get(index) : null; } } @Override @Nullable public Map.Entry<Range<K>, V> getEntry(K key) { int index = SortedLists.binarySearch(ranges, Range.<K>lowerBoundFn(), Cut.belowValue(key), KeyPresentBehavior.ANY_PRESENT, KeyAbsentBehavior.NEXT_LOWER); if (index == -1) { return null; } else { Range<K> range = ranges.get(index); return range.contains(key) ? Maps.immutableEntry(range, values.get(index)) : null; } } @Override public Range<K> span() { if (ranges.isEmpty()) { throw new NoSuchElementException(); } Range<K> firstRange = ranges.get(0); Range<K> lastRange = ranges.get(ranges.size() - 1); return Range.create(firstRange.lowerBound, lastRange.upperBound); } @Override public void put(Range<K> range, V value) { throw new UnsupportedOperationException(); } @Override public void putAll(RangeMap<K, V> rangeMap) { throw new UnsupportedOperationException(); } @Override public void clear() { throw new UnsupportedOperationException(); } @Override public void remove(Range<K> range) { throw new UnsupportedOperationException(); } @Override public ImmutableMap<Range<K>, V> asMapOfRanges() { if (ranges.isEmpty()) { return ImmutableMap.of(); } RegularImmutableSortedSet<Range<K>> rangeSet = new RegularImmutableSortedSet<Range<K>>(ranges, Range.RANGE_LEX_ORDERING); return new ImmutableSortedMap<Range<K>, V>(rangeSet, values); } @Override public ImmutableMap<Range<K>, V> asDescendingMapOfRanges() { if (ranges.isEmpty()) { return ImmutableMap.of(); } RegularImmutableSortedSet<Range<K>> rangeSet = new RegularImmutableSortedSet<Range<K>>(ranges.reverse(), Range.RANGE_LEX_ORDERING.reverse()); return new ImmutableSortedMap<Range<K>, V>(rangeSet, values.reverse()); } @Override public ImmutableRangeMap<K, V> subRangeMap(final Range<K> range) { if (checkNotNull(range).isEmpty()) { return ImmutableRangeMap.of(); } else if (ranges.isEmpty() || range.encloses(span())) { return this; } int lowerIndex = SortedLists.binarySearch(ranges, Range.<K>upperBoundFn(), range.lowerBound, KeyPresentBehavior.FIRST_AFTER, KeyAbsentBehavior.NEXT_HIGHER); int upperIndex = SortedLists.binarySearch(ranges, Range.<K>lowerBoundFn(), range.upperBound, KeyPresentBehavior.ANY_PRESENT, KeyAbsentBehavior.NEXT_HIGHER); if (lowerIndex >= upperIndex) { return ImmutableRangeMap.of(); } final int off = lowerIndex; final int len = upperIndex - lowerIndex; ImmutableList<Range<K>> subRanges = new ImmutableList<Range<K>>() { @Override public int size() { return len; } @Override public Range<K> get(int index) { checkElementIndex(index, len); if (index == 0 || index == len - 1) { return ranges.get(index + off).intersection(range); } else { return ranges.get(index + off); } } @Override boolean isPartialView() { return true; } }; final ImmutableRangeMap<K, V> outer = this; return new ImmutableRangeMap<K, V>(subRanges, values.subList(lowerIndex, upperIndex)) { @Override public ImmutableRangeMap<K, V> subRangeMap(Range<K> subRange) { if (range.isConnected(subRange)) { return outer.subRangeMap(subRange.intersection(range)); } else { return ImmutableRangeMap.of(); } } }; } @Override public int hashCode() { return asMapOfRanges().hashCode(); } @Override public boolean equals(@Nullable Object o) { if (o instanceof RangeMap) { RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o; return asMapOfRanges().equals(rangeMap.asMapOfRanges()); } return false; } @Override public String toString() { return asMapOfRanges().toString(); } /** * This class is used to serialize ImmutableRangeMap instances. * Serializes the {@link #asMapOfRanges()} form. */ private static class SerializedForm<K extends Comparable<?>, V> implements Serializable { private final ImmutableMap<Range<K>, V> mapOfRanges; SerializedForm(ImmutableMap<Range<K>, V> mapOfRanges) { this.mapOfRanges = mapOfRanges; } Object readResolve() { if (mapOfRanges.isEmpty()) { return of(); } else { return createRangeMap(); } } Object createRangeMap() { Builder<K, V> builder = new Builder<K, V>(); for (Entry<Range<K>, V> entry : mapOfRanges.entrySet()) { builder.put(entry.getKey(), entry.getValue()); } return builder.build(); } private static final long serialVersionUID = 0; } Object writeReplace() { return new SerializedForm<K, V>(asMapOfRanges()); } private static final long serialVersionUID = 0; }