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.DoNotCall;
027import com.google.errorprone.annotations.DoNotMock;
028import java.io.Serializable;
029import java.util.Collections;
030import java.util.List;
031import java.util.Map;
032import java.util.Map.Entry;
033import java.util.NoSuchElementException;
034import java.util.function.BiFunction;
035import java.util.function.Function;
036import java.util.stream.Collector;
037import javax.annotation.CheckForNull;
038import org.checkerframework.checker.nullness.qual.Nullable;
039
040/**
041 * A {@link RangeMap} whose contents will never change, with many other important properties
042 * detailed at {@link ImmutableCollection}.
043 *
044 * @author Louis Wasserman
045 * @since 14.0
046 */
047@Beta
048@GwtIncompatible // NavigableMap
049@ElementTypesAreNonnullByDefault
050public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K, V>, Serializable {
051
052  private static final ImmutableRangeMap<Comparable<?>, Object> EMPTY =
053      new ImmutableRangeMap<>(ImmutableList.<Range<Comparable<?>>>of(), ImmutableList.of());
054
055  /**
056   * Returns a {@code Collector} that accumulates the input elements into a new {@code
057   * ImmutableRangeMap}. As in {@link Builder}, overlapping ranges are not permitted.
058   *
059   * @since 23.1
060   */
061  public static <T extends @Nullable Object, K extends Comparable<? super K>, V>
062      Collector<T, ?, ImmutableRangeMap<K, V>> toImmutableRangeMap(
063          Function<? super T, Range<K>> keyFunction,
064          Function<? super T, ? extends V> valueFunction) {
065    return CollectCollectors.toImmutableRangeMap(keyFunction, valueFunction);
066  }
067
068  /**
069   * Returns an empty immutable range map.
070   *
071   * <p><b>Performance note:</b> the instance returned is a singleton.
072   */
073  @SuppressWarnings("unchecked")
074  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() {
075    return (ImmutableRangeMap<K, V>) EMPTY;
076  }
077
078  /** Returns an immutable range map mapping a single range to a single value. */
079  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of(Range<K> range, V value) {
080    return new ImmutableRangeMap<>(ImmutableList.of(range), ImmutableList.of(value));
081  }
082
083  @SuppressWarnings("unchecked")
084  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> copyOf(
085      RangeMap<K, ? extends V> rangeMap) {
086    if (rangeMap instanceof ImmutableRangeMap) {
087      return (ImmutableRangeMap<K, V>) rangeMap;
088    }
089    Map<Range<K>, ? extends V> map = rangeMap.asMapOfRanges();
090    ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<>(map.size());
091    ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(map.size());
092    for (Entry<Range<K>, ? extends V> entry : map.entrySet()) {
093      rangesBuilder.add(entry.getKey());
094      valuesBuilder.add(entry.getValue());
095    }
096    return new ImmutableRangeMap<>(rangesBuilder.build(), valuesBuilder.build());
097  }
098
099  /** Returns a new builder for an immutable range map. */
100  public static <K extends Comparable<?>, V> Builder<K, V> builder() {
101    return new Builder<>();
102  }
103
104  /**
105   * A builder for immutable range maps. Overlapping ranges are prohibited.
106   *
107   * @since 14.0
108   */
109  @DoNotMock
110  public static final class Builder<K extends Comparable<?>, V> {
111    private final List<Entry<Range<K>, V>> entries;
112
113    public Builder() {
114      this.entries = Lists.newArrayList();
115    }
116
117    /**
118     * Associates the specified range with the specified value.
119     *
120     * @throws IllegalArgumentException if {@code range} is empty
121     */
122    @CanIgnoreReturnValue
123    public Builder<K, V> put(Range<K> range, V value) {
124      checkNotNull(range);
125      checkNotNull(value);
126      checkArgument(!range.isEmpty(), "Range must not be empty, but was %s", range);
127      entries.add(Maps.immutableEntry(range, value));
128      return this;
129    }
130
131    /** Copies all associations from the specified range map into this builder. */
132    @CanIgnoreReturnValue
133    public Builder<K, V> putAll(RangeMap<K, ? extends V> rangeMap) {
134      for (Entry<Range<K>, ? extends V> entry : rangeMap.asMapOfRanges().entrySet()) {
135        put(entry.getKey(), entry.getValue());
136      }
137      return this;
138    }
139
140    @CanIgnoreReturnValue
141    Builder<K, V> combine(Builder<K, V> builder) {
142      entries.addAll(builder.entries);
143      return this;
144    }
145
146    /**
147     * Returns an {@code ImmutableRangeMap} containing the associations previously added to this
148     * builder.
149     *
150     * @throws IllegalArgumentException if any two ranges inserted into this builder overlap
151     */
152    public ImmutableRangeMap<K, V> build() {
153      Collections.sort(entries, Range.<K>rangeLexOrdering().onKeys());
154      ImmutableList.Builder<Range<K>> rangesBuilder = new ImmutableList.Builder<>(entries.size());
155      ImmutableList.Builder<V> valuesBuilder = new ImmutableList.Builder<V>(entries.size());
156      for (int i = 0; i < entries.size(); i++) {
157        Range<K> range = entries.get(i).getKey();
158        if (i > 0) {
159          Range<K> prevRange = entries.get(i - 1).getKey();
160          if (range.isConnected(prevRange) && !range.intersection(prevRange).isEmpty()) {
161            throw new IllegalArgumentException(
162                "Overlapping ranges: range " + prevRange + " overlaps with entry " + range);
163          }
164        }
165        rangesBuilder.add(range);
166        valuesBuilder.add(entries.get(i).getValue());
167      }
168      return new ImmutableRangeMap<>(rangesBuilder.build(), valuesBuilder.build());
169    }
170  }
171
172  private final transient ImmutableList<Range<K>> ranges;
173  private final transient ImmutableList<V> values;
174
175  ImmutableRangeMap(ImmutableList<Range<K>> ranges, ImmutableList<V> values) {
176    this.ranges = ranges;
177    this.values = values;
178  }
179
180  @Override
181  @CheckForNull
182  public V get(K key) {
183    int index =
184        SortedLists.binarySearch(
185            ranges,
186            Range.<K>lowerBoundFn(),
187            Cut.belowValue(key),
188            KeyPresentBehavior.ANY_PRESENT,
189            KeyAbsentBehavior.NEXT_LOWER);
190    if (index == -1) {
191      return null;
192    } else {
193      Range<K> range = ranges.get(index);
194      return range.contains(key) ? values.get(index) : null;
195    }
196  }
197
198  @Override
199  @CheckForNull
200  public Entry<Range<K>, V> getEntry(K key) {
201    int index =
202        SortedLists.binarySearch(
203            ranges,
204            Range.<K>lowerBoundFn(),
205            Cut.belowValue(key),
206            KeyPresentBehavior.ANY_PRESENT,
207            KeyAbsentBehavior.NEXT_LOWER);
208    if (index == -1) {
209      return null;
210    } else {
211      Range<K> range = ranges.get(index);
212      return range.contains(key) ? Maps.immutableEntry(range, values.get(index)) : null;
213    }
214  }
215
216  @Override
217  public Range<K> span() {
218    if (ranges.isEmpty()) {
219      throw new NoSuchElementException();
220    }
221    Range<K> firstRange = ranges.get(0);
222    Range<K> lastRange = ranges.get(ranges.size() - 1);
223    return Range.create(firstRange.lowerBound, lastRange.upperBound);
224  }
225
226  /**
227   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
228   *
229   * @throws UnsupportedOperationException always
230   * @deprecated Unsupported operation.
231   */
232  @Deprecated
233  @Override
234  @DoNotCall("Always throws UnsupportedOperationException")
235  public final void put(Range<K> range, V value) {
236    throw new UnsupportedOperationException();
237  }
238
239  /**
240   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
241   *
242   * @throws UnsupportedOperationException always
243   * @deprecated Unsupported operation.
244   */
245  @Deprecated
246  @Override
247  @DoNotCall("Always throws UnsupportedOperationException")
248  public final void putCoalescing(Range<K> range, V value) {
249    throw new UnsupportedOperationException();
250  }
251
252  /**
253   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
254   *
255   * @throws UnsupportedOperationException always
256   * @deprecated Unsupported operation.
257   */
258  @Deprecated
259  @Override
260  @DoNotCall("Always throws UnsupportedOperationException")
261  public final void putAll(RangeMap<K, V> rangeMap) {
262    throw new UnsupportedOperationException();
263  }
264
265  /**
266   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
267   *
268   * @throws UnsupportedOperationException always
269   * @deprecated Unsupported operation.
270   */
271  @Deprecated
272  @Override
273  @DoNotCall("Always throws UnsupportedOperationException")
274  public final void clear() {
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  @DoNotCall("Always throws UnsupportedOperationException")
287  public final void remove(Range<K> range) {
288    throw new UnsupportedOperationException();
289  }
290
291  /**
292   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
293   *
294   * @throws UnsupportedOperationException always
295   * @deprecated Unsupported operation.
296   */
297  @Deprecated
298  @Override
299  @DoNotCall("Always throws UnsupportedOperationException")
300  public final void merge(
301      Range<K> range,
302      @CheckForNull V value,
303      BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> remappingFunction) {
304    throw new UnsupportedOperationException();
305  }
306
307  @Override
308  public ImmutableMap<Range<K>, V> asMapOfRanges() {
309    if (ranges.isEmpty()) {
310      return ImmutableMap.of();
311    }
312    RegularImmutableSortedSet<Range<K>> rangeSet =
313        new RegularImmutableSortedSet<>(ranges, Range.<K>rangeLexOrdering());
314    return new ImmutableSortedMap<>(rangeSet, values);
315  }
316
317  @Override
318  public ImmutableMap<Range<K>, V> asDescendingMapOfRanges() {
319    if (ranges.isEmpty()) {
320      return ImmutableMap.of();
321    }
322    RegularImmutableSortedSet<Range<K>> rangeSet =
323        new RegularImmutableSortedSet<>(ranges.reverse(), Range.<K>rangeLexOrdering().reverse());
324    return new ImmutableSortedMap<>(rangeSet, values.reverse());
325  }
326
327  @Override
328  public ImmutableRangeMap<K, V> subRangeMap(final Range<K> range) {
329    if (checkNotNull(range).isEmpty()) {
330      return ImmutableRangeMap.of();
331    } else if (ranges.isEmpty() || range.encloses(span())) {
332      return this;
333    }
334    int lowerIndex =
335        SortedLists.binarySearch(
336            ranges,
337            Range.<K>upperBoundFn(),
338            range.lowerBound,
339            KeyPresentBehavior.FIRST_AFTER,
340            KeyAbsentBehavior.NEXT_HIGHER);
341    int upperIndex =
342        SortedLists.binarySearch(
343            ranges,
344            Range.<K>lowerBoundFn(),
345            range.upperBound,
346            KeyPresentBehavior.ANY_PRESENT,
347            KeyAbsentBehavior.NEXT_HIGHER);
348    if (lowerIndex >= upperIndex) {
349      return ImmutableRangeMap.of();
350    }
351    final int off = lowerIndex;
352    final int len = upperIndex - lowerIndex;
353    ImmutableList<Range<K>> subRanges =
354        new ImmutableList<Range<K>>() {
355          @Override
356          public int size() {
357            return len;
358          }
359
360          @Override
361          public Range<K> get(int index) {
362            checkElementIndex(index, len);
363            if (index == 0 || index == len - 1) {
364              return ranges.get(index + off).intersection(range);
365            } else {
366              return ranges.get(index + off);
367            }
368          }
369
370          @Override
371          boolean isPartialView() {
372            return true;
373          }
374        };
375    final ImmutableRangeMap<K, V> outer = this;
376    return new ImmutableRangeMap<K, V>(subRanges, values.subList(lowerIndex, upperIndex)) {
377      @Override
378      public ImmutableRangeMap<K, V> subRangeMap(Range<K> subRange) {
379        if (range.isConnected(subRange)) {
380          return outer.subRangeMap(subRange.intersection(range));
381        } else {
382          return ImmutableRangeMap.of();
383        }
384      }
385    };
386  }
387
388  @Override
389  public int hashCode() {
390    return asMapOfRanges().hashCode();
391  }
392
393  @Override
394  public boolean equals(@CheckForNull Object o) {
395    if (o instanceof RangeMap) {
396      RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o;
397      return asMapOfRanges().equals(rangeMap.asMapOfRanges());
398    }
399    return false;
400  }
401
402  @Override
403  public String toString() {
404    return asMapOfRanges().toString();
405  }
406
407  /**
408   * This class is used to serialize ImmutableRangeMap instances. Serializes the {@link
409   * #asMapOfRanges()} form.
410   */
411  private static class SerializedForm<K extends Comparable<?>, V> implements Serializable {
412
413    private final ImmutableMap<Range<K>, V> mapOfRanges;
414
415    SerializedForm(ImmutableMap<Range<K>, V> mapOfRanges) {
416      this.mapOfRanges = mapOfRanges;
417    }
418
419    Object readResolve() {
420      if (mapOfRanges.isEmpty()) {
421        return of();
422      } else {
423        return createRangeMap();
424      }
425    }
426
427    Object createRangeMap() {
428      Builder<K, V> builder = new Builder<>();
429      for (Entry<Range<K>, V> entry : mapOfRanges.entrySet()) {
430        builder.put(entry.getKey(), entry.getValue());
431      }
432      return builder.build();
433    }
434
435    private static final long serialVersionUID = 0;
436  }
437
438  Object writeReplace() {
439    return new SerializedForm<>(asMapOfRanges());
440  }
441
442  private static final long serialVersionUID = 0;
443}