Source code

001/*
002 * Copyright (C) 2012 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 License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.collect;
016
017import static com.google.common.base.Preconditions.checkArgument;
018import static com.google.common.base.Preconditions.checkElementIndex;
019import static com.google.common.base.Preconditions.checkNotNull;
020
021import com.google.common.annotations.Beta;
022import com.google.common.annotations.GwtIncompatible;
023import com.google.common.collect.SortedLists.KeyAbsentBehavior;
024import com.google.common.collect.SortedLists.KeyPresentBehavior;
025import com.google.errorprone.annotations.CanIgnoreReturnValue;
026import com.google.errorprone.annotations.DoNotMock;
027import java.io.Serializable;
028import java.util.Collections;
029import java.util.List;
030import java.util.Map;
031import java.util.Map.Entry;
032import java.util.NoSuchElementException;
033import java.util.function.BiFunction;
034import java.util.function.Function;
035import java.util.stream.Collector;
036import org.checkerframework.checker.nullness.qual.Nullable;
037
038/**
039 * A {@link RangeMap} whose contents will never change, with many other important properties
040 * detailed at {@link ImmutableCollection}.
041 *
042 * @author Louis Wasserman
043 * @since 14.0
044 */
045@Beta
046@GwtIncompatible // NavigableMap
047public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K, V>, Serializable {
048
049  private static final ImmutableRangeMap<Comparable<?>, Object> EMPTY =
050      new ImmutableRangeMap<>(ImmutableList.<Range<Comparable<?>>>of(), ImmutableList.of());
051
052  /**
053   * Returns a {@code Collector} that accumulates the input elements into a new {@code
054   * ImmutableRangeMap}. As in {@link Builder}, overlapping ranges are not permitted.
055   *
056   *
057   * @since 23.1
058   */
059  public static <T, K extends Comparable<? super K>, V>
060      Collector<T, ?, ImmutableRangeMap<K, V>> toImmutableRangeMap(
061          Function<? super T, Range<K>> keyFunction,
062          Function<? super T, ? extends V> valueFunction) {
063    return CollectCollectors.toImmutableRangeMap(keyFunction, valueFunction);
064  }
065
066  /** Returns an empty immutable range map. */
067  @SuppressWarnings("unchecked")
068  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() {
069    return (ImmutableRangeMap<K, V>) EMPTY;
070  }
071
072  /** Returns an immutable range map mapping a single range to a single value. */
073  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of(Range<K> range, V value) {
074    return new ImmutableRangeMap<>(ImmutableList.of(range), ImmutableList.of(value));
075  }
076
077  @SuppressWarnings("unchecked")
078  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> copyOf(
079      RangeMap<K, ? extends V> rangeMap) {
080    if (rangeMap instanceof ImmutableRangeMap) {
081      return (ImmutableRangeMap<K, V>) rangeMap;
082    }
083    Map<Range<K>, ? extends V> map = rangeMap.asMapOfRanges();
084    ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<>(map.size());
085    ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(map.size());
086    for (Entry<Range<K>, ? extends V> entry : map.entrySet()) {
087      rangesBuilder.add(entry.getKey());
088      valuesBuilder.add(entry.getValue());
089    }
090    return new ImmutableRangeMap<>(rangesBuilder.build(), valuesBuilder.build());
091  }
092
093  /** Returns a new builder for an immutable range map. */
094  public static <K extends Comparable<?>, V> Builder<K, V> builder() {
095    return new Builder<>();
096  }
097
098  /**
099   * A builder for immutable range maps. Overlapping ranges are prohibited.
100   *
101   * @since 14.0
102   */
103  @DoNotMock
104  public static final class Builder<K extends Comparable<?>, V> {
105    private final List<Entry<Range<K>, V>> entries;
106
107    public Builder() {
108      this.entries = Lists.newArrayList();
109    }
110
111    /**
112     * Associates the specified range with the specified value.
113     *
114     * @throws IllegalArgumentException if {@code range} is empty
115     */
116    @CanIgnoreReturnValue
117    public Builder<K, V> put(Range<K> range, V value) {
118      checkNotNull(range);
119      checkNotNull(value);
120      checkArgument(!range.isEmpty(), "Range must not be empty, but was %s", range);
121      entries.add(Maps.immutableEntry(range, value));
122      return this;
123    }
124
125    /** Copies all associations from the specified range map into this builder. */
126    @CanIgnoreReturnValue
127    public Builder<K, V> putAll(RangeMap<K, ? extends V> rangeMap) {
128      for (Entry<Range<K>, ? extends V> entry : rangeMap.asMapOfRanges().entrySet()) {
129        put(entry.getKey(), entry.getValue());
130      }
131      return this;
132    }
133
134    @CanIgnoreReturnValue
135    Builder<K, V> combine(Builder<K, V> builder) {
136      entries.addAll(builder.entries);
137      return this;
138    }
139
140    /**
141     * Returns an {@code ImmutableRangeMap} containing the associations previously added to this
142     * builder.
143     *
144     * @throws IllegalArgumentException if any two ranges inserted into this builder overlap
145     */
146    public ImmutableRangeMap<K, V> build() {
147      Collections.sort(entries, Range.<K>rangeLexOrdering().onKeys());
148      ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<>(entries.size());
149      ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(entries.size());
150      for (int i = 0; i < entries.size(); i++) {
151        Range<K> range = entries.get(i).getKey();
152        if (i > 0) {
153          Range<K> prevRange = entries.get(i - 1).getKey();
154          if (range.isConnected(prevRange) && !range.intersection(prevRange).isEmpty()) {
155            throw new IllegalArgumentException(
156                "Overlapping ranges: range " + prevRange + " overlaps with entry " + range);
157          }
158        }
159        rangesBuilder.add(range);
160        valuesBuilder.add(entries.get(i).getValue());
161      }
162      return new ImmutableRangeMap<>(rangesBuilder.build(), valuesBuilder.build());
163    }
164  }
165
166  private final transient ImmutableList<Range<K>> ranges;
167  private final transient ImmutableList<V> values;
168
169  ImmutableRangeMap(ImmutableList<Range<K>> ranges, ImmutableList<V> values) {
170    this.ranges = ranges;
171    this.values = values;
172  }
173
174  @Override
175  public @Nullable V get(K key) {
176    int index =
177        SortedLists.binarySearch(
178            ranges,
179            Range.<K>lowerBoundFn(),
180            Cut.belowValue(key),
181            KeyPresentBehavior.ANY_PRESENT,
182            KeyAbsentBehavior.NEXT_LOWER);
183    if (index == -1) {
184      return null;
185    } else {
186      Range<K> range = ranges.get(index);
187      return range.contains(key) ? values.get(index) : null;
188    }
189  }
190
191  @Override
192  public @Nullable Entry<Range<K>, V> getEntry(K key) {
193    int index =
194        SortedLists.binarySearch(
195            ranges,
196            Range.<K>lowerBoundFn(),
197            Cut.belowValue(key),
198            KeyPresentBehavior.ANY_PRESENT,
199            KeyAbsentBehavior.NEXT_LOWER);
200    if (index == -1) {
201      return null;
202    } else {
203      Range<K> range = ranges.get(index);
204      return range.contains(key) ? Maps.immutableEntry(range, values.get(index)) : null;
205    }
206  }
207
208  @Override
209  public Range<K> span() {
210    if (ranges.isEmpty()) {
211      throw new NoSuchElementException();
212    }
213    Range<K> firstRange = ranges.get(0);
214    Range<K> lastRange = ranges.get(ranges.size() - 1);
215    return Range.create(firstRange.lowerBound, lastRange.upperBound);
216  }
217
218  /**
219   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
220   *
221   * @throws UnsupportedOperationException always
222   * @deprecated Unsupported operation.
223   */
224  @Deprecated
225  @Override
226  public void put(Range<K> range, V value) {
227    throw new UnsupportedOperationException();
228  }
229
230  /**
231   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
232   *
233   * @throws UnsupportedOperationException always
234   * @deprecated Unsupported operation.
235   */
236  @Deprecated
237  @Override
238  public void putCoalescing(Range<K> range, V value) {
239    throw new UnsupportedOperationException();
240  }
241
242  /**
243   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
244   *
245   * @throws UnsupportedOperationException always
246   * @deprecated Unsupported operation.
247   */
248  @Deprecated
249  @Override
250  public void putAll(RangeMap<K, V> rangeMap) {
251    throw new UnsupportedOperationException();
252  }
253
254  /**
255   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
256   *
257   * @throws UnsupportedOperationException always
258   * @deprecated Unsupported operation.
259   */
260  @Deprecated
261  @Override
262  public void clear() {
263    throw new UnsupportedOperationException();
264  }
265
266  /**
267   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
268   *
269   * @throws UnsupportedOperationException always
270   * @deprecated Unsupported operation.
271   */
272  @Deprecated
273  @Override
274  public void remove(Range<K> range) {
275    throw new UnsupportedOperationException();
276  }
277
278  /**
279   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
280   *
281   * @throws UnsupportedOperationException always
282   * @deprecated Unsupported operation.
283   */
284  @Deprecated
285  @Override
286  public void merge(
287      Range<K> range,
288      @Nullable V value,
289      BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
290    throw new UnsupportedOperationException();
291  }
292
293  @Override
294  public ImmutableMap<Range<K>, V> asMapOfRanges() {
295    if (ranges.isEmpty()) {
296      return ImmutableMap.of();
297    }
298    RegularImmutableSortedSet<Range<K>> rangeSet =
299        new RegularImmutableSortedSet<>(ranges, Range.<K>rangeLexOrdering());
300    return new ImmutableSortedMap<>(rangeSet, values);
301  }
302
303  @Override
304  public ImmutableMap<Range<K>, V> asDescendingMapOfRanges() {
305    if (ranges.isEmpty()) {
306      return ImmutableMap.of();
307    }
308    RegularImmutableSortedSet<Range<K>> rangeSet =
309        new RegularImmutableSortedSet<>(ranges.reverse(), Range.<K>rangeLexOrdering().reverse());
310    return new ImmutableSortedMap<>(rangeSet, values.reverse());
311  }
312
313  @Override
314  public ImmutableRangeMap<K, V> subRangeMap(final Range<K> range) {
315    if (checkNotNull(range).isEmpty()) {
316      return ImmutableRangeMap.of();
317    } else if (ranges.isEmpty() || range.encloses(span())) {
318      return this;
319    }
320    int lowerIndex =
321        SortedLists.binarySearch(
322            ranges,
323            Range.<K>upperBoundFn(),
324            range.lowerBound,
325            KeyPresentBehavior.FIRST_AFTER,
326            KeyAbsentBehavior.NEXT_HIGHER);
327    int upperIndex =
328        SortedLists.binarySearch(
329            ranges,
330            Range.<K>lowerBoundFn(),
331            range.upperBound,
332            KeyPresentBehavior.ANY_PRESENT,
333            KeyAbsentBehavior.NEXT_HIGHER);
334    if (lowerIndex >= upperIndex) {
335      return ImmutableRangeMap.of();
336    }
337    final int off = lowerIndex;
338    final int len = upperIndex - lowerIndex;
339    ImmutableList<Range<K>> subRanges =
340        new ImmutableList<Range<K>>() {
341          @Override
342          public int size() {
343            return len;
344          }
345
346          @Override
347          public Range<K> get(int index) {
348            checkElementIndex(index, len);
349            if (index == 0 || index == len - 1) {
350              return ranges.get(index + off).intersection(range);
351            } else {
352              return ranges.get(index + off);
353            }
354          }
355
356          @Override
357          boolean isPartialView() {
358            return true;
359          }
360        };
361    final ImmutableRangeMap<K, V> outer = this;
362    return new ImmutableRangeMap<K, V>(subRanges, values.subList(lowerIndex, upperIndex)) {
363      @Override
364      public ImmutableRangeMap<K, V> subRangeMap(Range<K> subRange) {
365        if (range.isConnected(subRange)) {
366          return outer.subRangeMap(subRange.intersection(range));
367        } else {
368          return ImmutableRangeMap.of();
369        }
370      }
371    };
372  }
373
374  @Override
375  public int hashCode() {
376    return asMapOfRanges().hashCode();
377  }
378
379  @Override
380  public boolean equals(@Nullable Object o) {
381    if (o instanceof RangeMap) {
382      RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o;
383      return asMapOfRanges().equals(rangeMap.asMapOfRanges());
384    }
385    return false;
386  }
387
388  @Override
389  public String toString() {
390    return asMapOfRanges().toString();
391  }
392
393  /**
394   * This class is used to serialize ImmutableRangeMap instances. Serializes the {@link
395   * #asMapOfRanges()} form.
396   */
397  private static class SerializedForm<K extends Comparable<?>, V> implements Serializable {
398
399    private final ImmutableMap<Range<K>, V> mapOfRanges;
400
401    SerializedForm(ImmutableMap<Range<K>, V> mapOfRanges) {
402      this.mapOfRanges = mapOfRanges;
403    }
404
405    Object readResolve() {
406      if (mapOfRanges.isEmpty()) {
407        return of();
408      } else {
409        return createRangeMap();
410      }
411    }
412
413    Object createRangeMap() {
414      Builder<K, V> builder = new Builder<>();
415      for (Entry<Range<K>, V> entry : mapOfRanges.entrySet()) {
416        builder.put(entry.getKey(), entry.getValue());
417      }
418      return builder.build();
419    }
420
421    private static final long serialVersionUID = 0;
422  }
423
424  Object writeReplace() {
425    return new SerializedForm<>(asMapOfRanges());
426  }
427
428  private static final long serialVersionUID = 0;
429}