001/*
002 * Copyright (C) 2012 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect;
018
019import static com.google.common.base.Preconditions.checkArgument;
020import static com.google.common.base.Preconditions.checkNotNull;
021import static com.google.common.base.Predicates.compose;
022import static com.google.common.base.Predicates.in;
023import static com.google.common.base.Predicates.not;
024
025import com.google.common.annotations.Beta;
026import com.google.common.annotations.GwtIncompatible;
027import com.google.common.base.Objects;
028import com.google.common.base.Predicate;
029
030import java.util.AbstractMap;
031import java.util.AbstractSet;
032import java.util.Collection;
033import java.util.Collections;
034import java.util.Iterator;
035import java.util.List;
036import java.util.Map;
037import java.util.Map.Entry;
038import java.util.NavigableMap;
039import java.util.NoSuchElementException;
040import java.util.Set;
041
042import javax.annotation.Nullable;
043
044/**
045 * An implementation of {@code RangeMap} based on a {@code TreeMap}, supporting
046 * all optional operations.
047 *
048 * <p>Like all {@code RangeMap} implementations, this supports neither null
049 * keys nor null values.
050 *
051 * @author Louis Wasserman
052 * @since 14.0
053 */
054@Beta
055@GwtIncompatible("NavigableMap")
056public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K, V> {
057
058  private final NavigableMap<Cut<K>, RangeMapEntry<K, V>> entriesByLowerBound;
059
060  public static <K extends Comparable, V> TreeRangeMap<K, V> create() {
061    return new TreeRangeMap<K, V>();
062  }
063
064  private TreeRangeMap() {
065    this.entriesByLowerBound = Maps.newTreeMap();
066  }
067
068  private static final class RangeMapEntry<K extends Comparable, V>
069      extends AbstractMapEntry<Range<K>, V> {
070    private final Range<K> range;
071    private final V value;
072
073    RangeMapEntry(Cut<K> lowerBound, Cut<K> upperBound, V value) {
074      this(Range.create(lowerBound, upperBound), value);
075    }
076
077    RangeMapEntry(Range<K> range, V value) {
078      this.range = range;
079      this.value = value;
080    }
081
082    @Override
083    public Range<K> getKey() {
084      return range;
085    }
086
087    @Override
088    public V getValue() {
089      return value;
090    }
091
092    public boolean contains(K value) {
093      return range.contains(value);
094    }
095
096    Cut<K> getLowerBound() {
097      return range.lowerBound;
098    }
099
100    Cut<K> getUpperBound() {
101      return range.upperBound;
102    }
103  }
104
105  @Override
106  @Nullable
107  public V get(K key) {
108    Entry<Range<K>, V> entry = getEntry(key);
109    return (entry == null) ? null : entry.getValue();
110  }
111
112  @Override
113  @Nullable
114  public Entry<Range<K>, V> getEntry(K key) {
115    Map.Entry<Cut<K>, RangeMapEntry<K, V>> mapEntry =
116        entriesByLowerBound.floorEntry(Cut.belowValue(key));
117    if (mapEntry != null && mapEntry.getValue().contains(key)) {
118      return mapEntry.getValue();
119    } else {
120      return null;
121    }
122  }
123
124  @Override
125  public void put(Range<K> range, V value) {
126    if (!range.isEmpty()) {
127      checkNotNull(value);
128      remove(range);
129      entriesByLowerBound.put(range.lowerBound, new RangeMapEntry<K, V>(range, value));
130    }
131  }
132
133  @Override
134  public void putAll(RangeMap<K, V> rangeMap) {
135    for (Map.Entry<Range<K>, V> entry : rangeMap.asMapOfRanges().entrySet()) {
136      put(entry.getKey(), entry.getValue());
137    }
138  }
139
140  @Override
141  public void clear() {
142    entriesByLowerBound.clear();
143  }
144
145  @Override
146  public Range<K> span() {
147    Entry<Cut<K>, RangeMapEntry<K, V>> firstEntry = entriesByLowerBound.firstEntry();
148    Entry<Cut<K>, RangeMapEntry<K, V>> lastEntry = entriesByLowerBound.lastEntry();
149    if (firstEntry == null) {
150      throw new NoSuchElementException();
151    }
152    return Range.create(
153        firstEntry.getValue().getKey().lowerBound,
154        lastEntry.getValue().getKey().upperBound);
155  }
156
157  private void putRangeMapEntry(Cut<K> lowerBound, Cut<K> upperBound, V value) {
158    entriesByLowerBound.put(lowerBound, new RangeMapEntry<K, V>(lowerBound, upperBound, value));
159  }
160
161  @Override
162  public void remove(Range<K> rangeToRemove) {
163    if (rangeToRemove.isEmpty()) {
164      return;
165    }
166
167    /*
168     * The comments for this method will use [ ] to indicate the bounds of rangeToRemove and ( ) to
169     * indicate the bounds of ranges in the range map.
170     */
171    Map.Entry<Cut<K>, RangeMapEntry<K, V>> mapEntryBelowToTruncate =
172        entriesByLowerBound.lowerEntry(rangeToRemove.lowerBound);
173    if (mapEntryBelowToTruncate != null) {
174      // we know ( [
175      RangeMapEntry<K, V> rangeMapEntry = mapEntryBelowToTruncate.getValue();
176      if (rangeMapEntry.getUpperBound().compareTo(rangeToRemove.lowerBound) > 0) {
177        // we know ( [ )
178        if (rangeMapEntry.getUpperBound().compareTo(rangeToRemove.upperBound) > 0) {
179          // we know ( [ ] ), so insert the range ] ) back into the map --
180          // it's being split apart
181          putRangeMapEntry(rangeToRemove.upperBound, rangeMapEntry.getUpperBound(),
182              mapEntryBelowToTruncate.getValue().getValue());
183        }
184        // overwrite mapEntryToTruncateBelow with a truncated range
185        putRangeMapEntry(rangeMapEntry.getLowerBound(), rangeToRemove.lowerBound,
186            mapEntryBelowToTruncate.getValue().getValue());
187      }
188    }
189
190    Map.Entry<Cut<K>, RangeMapEntry<K, V>> mapEntryAboveToTruncate =
191        entriesByLowerBound.lowerEntry(rangeToRemove.upperBound);
192    if (mapEntryAboveToTruncate != null) {
193      // we know ( ]
194      RangeMapEntry<K, V> rangeMapEntry = mapEntryAboveToTruncate.getValue();
195      if (rangeMapEntry.getUpperBound().compareTo(rangeToRemove.upperBound) > 0) {
196        // we know ( ] ), and since we dealt with truncating below already,
197        // we know [ ( ] )
198        putRangeMapEntry(rangeToRemove.upperBound, rangeMapEntry.getUpperBound(),
199            mapEntryAboveToTruncate.getValue().getValue());
200        entriesByLowerBound.remove(rangeToRemove.lowerBound);
201      }
202    }
203    entriesByLowerBound.subMap(rangeToRemove.lowerBound, rangeToRemove.upperBound).clear();
204  }
205
206  @Override
207  public Map<Range<K>, V> asMapOfRanges() {
208    return new AsMapOfRanges();
209  }
210
211  private final class AsMapOfRanges extends AbstractMap<Range<K>, V> {
212
213    @Override
214    public boolean containsKey(@Nullable Object key) {
215      return get(key) != null;
216    }
217
218    @Override
219    public V get(@Nullable Object key) {
220      if (key instanceof Range) {
221        Range<?> range = (Range<?>) key;
222        RangeMapEntry<K, V> rangeMapEntry = entriesByLowerBound.get(range.lowerBound);
223        if (rangeMapEntry != null && rangeMapEntry.getKey().equals(range)) {
224          return rangeMapEntry.getValue();
225        }
226      }
227      return null;
228    }
229
230    @Override
231    public Set<Entry<Range<K>, V>> entrySet() {
232      return new AbstractSet<Entry<Range<K>, V>>() {
233
234        @SuppressWarnings("unchecked") // it's safe to upcast iterators
235        @Override
236        public Iterator<Entry<Range<K>, V>> iterator() {
237          return (Iterator) entriesByLowerBound.values().iterator();
238        }
239
240        @Override
241        public int size() {
242          return entriesByLowerBound.size();
243        }
244      };
245    }
246  }
247  
248  @Override
249  public RangeMap<K, V> subRangeMap(Range<K> subRange) {
250    if (subRange.equals(Range.all())) {
251      return this;
252    } else {
253      return new SubRangeMap(subRange);
254    }
255  }
256  
257  @SuppressWarnings("unchecked")
258  private RangeMap<K, V> emptySubRangeMap() {
259    return EMPTY_SUB_RANGE_MAP;
260  }
261  
262  private static final RangeMap EMPTY_SUB_RANGE_MAP = 
263      new RangeMap() {
264        @Override
265        @Nullable
266        public Object get(Comparable key) {
267          return null;
268        }
269
270        @Override
271        @Nullable
272        public Entry<Range, Object> getEntry(Comparable key) {
273          return null;
274        }
275
276        @Override
277        public Range span() {
278          throw new NoSuchElementException();
279        }
280
281        @Override
282        public void put(Range range, Object value) {
283          checkNotNull(range);
284          throw new IllegalArgumentException(
285              "Cannot insert range " + range + " into an empty subRangeMap");
286        }
287
288        @Override
289        public void putAll(RangeMap rangeMap) {
290          if (!rangeMap.asMapOfRanges().isEmpty()) {
291            throw new IllegalArgumentException(
292                "Cannot putAll(nonEmptyRangeMap) into an empty " + "subRangeMap");
293          }
294        }
295
296        @Override
297        public void clear() {}
298
299        @Override
300        public void remove(Range range) {
301          checkNotNull(range);
302        }
303
304        @Override
305        public Map<Range, Object> asMapOfRanges() {
306          return Collections.emptyMap();
307        }
308
309        @Override
310        public RangeMap subRangeMap(Range range) {
311          checkNotNull(range);
312          return this;
313        }
314      };
315  
316  private class SubRangeMap implements RangeMap<K, V> {
317
318    private final Range<K> subRange;
319    
320    SubRangeMap(Range<K> subRange) {
321      this.subRange = subRange;
322    }
323
324    @Override
325    @Nullable
326    public V get(K key) {
327      return subRange.contains(key)
328          ? TreeRangeMap.this.get(key)
329          : null;
330    }
331
332    @Override
333    @Nullable
334    public Entry<Range<K>, V> getEntry(K key) {
335      if (subRange.contains(key)) {
336        Entry<Range<K>, V> entry = TreeRangeMap.this.getEntry(key);
337        if (entry != null) {
338          return Maps.immutableEntry(entry.getKey().intersection(subRange), entry.getValue());
339        }
340      }
341      return null;
342    }
343
344    @Override
345    public Range<K> span() {
346      Cut<K> lowerBound;
347      Entry<Cut<K>, RangeMapEntry<K, V>> lowerEntry =
348          entriesByLowerBound.floorEntry(subRange.lowerBound);
349      if (lowerEntry != null && 
350          lowerEntry.getValue().getUpperBound().compareTo(subRange.lowerBound) > 0) {
351        lowerBound = subRange.lowerBound;
352      } else {
353        lowerBound = entriesByLowerBound.ceilingKey(subRange.lowerBound);
354        if (lowerBound == null || lowerBound.compareTo(subRange.upperBound) >= 0) {
355          throw new NoSuchElementException();
356        }
357      }
358      
359      Cut<K> upperBound;
360      Entry<Cut<K>, RangeMapEntry<K, V>> upperEntry = 
361          entriesByLowerBound.lowerEntry(subRange.upperBound);
362      if (upperEntry == null) {
363        throw new NoSuchElementException();
364      } else if (upperEntry.getValue().getUpperBound().compareTo(subRange.upperBound) >= 0) {
365        upperBound = subRange.upperBound;
366      } else {
367        upperBound = upperEntry.getValue().getUpperBound();
368      }
369      return Range.create(lowerBound, upperBound);
370    }
371
372    @Override
373    public void put(Range<K> range, V value) {
374      checkArgument(subRange.encloses(range), 
375          "Cannot put range %s into a subRangeMap(%s)", range, subRange);
376      TreeRangeMap.this.put(range, value);
377    }
378
379    @Override
380    public void putAll(RangeMap<K, V> rangeMap) {
381      if (rangeMap.asMapOfRanges().isEmpty()) {
382        return;
383      }
384      Range<K> span = rangeMap.span();
385      checkArgument(subRange.encloses(span), 
386          "Cannot putAll rangeMap with span %s into a subRangeMap(%s)", span, subRange);
387      TreeRangeMap.this.putAll(rangeMap);
388    }
389
390    @Override
391    public void clear() {
392      TreeRangeMap.this.remove(subRange);
393    }
394
395    @Override
396    public void remove(Range<K> range) {
397      if (range.isConnected(subRange)) {
398        TreeRangeMap.this.remove(range.intersection(subRange));
399      }
400    }
401
402    @Override
403    public RangeMap<K, V> subRangeMap(Range<K> range) {
404      if (!range.isConnected(subRange)) {
405        return emptySubRangeMap();
406      } else {
407        return TreeRangeMap.this.subRangeMap(range.intersection(subRange));
408      }
409    }
410
411    @Override
412    public Map<Range<K>, V> asMapOfRanges() {
413      return new SubRangeMapAsMap();
414    }
415
416    @Override
417    public boolean equals(@Nullable Object o) {
418      if (o instanceof RangeMap) {
419        RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o;
420        return asMapOfRanges().equals(rangeMap.asMapOfRanges());
421      }
422      return false;
423    }
424
425    @Override
426    public int hashCode() {
427      return asMapOfRanges().hashCode();
428    }
429
430    @Override
431    public String toString() {
432      return asMapOfRanges().toString();
433    }
434    
435    class SubRangeMapAsMap extends AbstractMap<Range<K>, V> {
436      
437      @Override
438      public boolean containsKey(Object key) {
439        return get(key) != null;
440      }
441
442      @Override
443      public V get(Object key) {
444        try {
445          if (key instanceof Range) {
446            @SuppressWarnings("unchecked") // we catch ClassCastExceptions
447            Range<K> r = (Range<K>) key;
448            if (!subRange.encloses(r) || r.isEmpty()) {
449              return null;
450            }
451            RangeMapEntry<K, V> candidate = null;
452            if (r.lowerBound.compareTo(subRange.lowerBound) == 0) {
453              // r could be truncated on the left
454              Entry<Cut<K>, RangeMapEntry<K, V>> entry = 
455                  entriesByLowerBound.floorEntry(r.lowerBound);
456              if (entry != null) {
457                candidate = entry.getValue();
458              }
459            } else {
460              candidate = entriesByLowerBound.get(r.lowerBound);
461            }
462            
463            if (candidate != null && candidate.getKey().isConnected(subRange)
464                && candidate.getKey().intersection(subRange).equals(r)) {
465              return candidate.getValue();
466            }
467          }
468        } catch (ClassCastException e) {
469          return null;
470        }
471        return null;
472      }
473
474      @Override
475      public V remove(Object key) {
476        V value = get(key);
477        if (value != null) {
478          @SuppressWarnings("unchecked") // it's definitely in the map, so safe
479          Range<K> range = (Range<K>) key;
480          TreeRangeMap.this.remove(range);
481          return value;
482        }
483        return null;
484      }
485
486      @Override
487      public void clear() {
488        SubRangeMap.this.clear();
489      }
490      
491      private boolean removeEntryIf(Predicate<? super Entry<Range<K>, V>> predicate) {
492        List<Range<K>> toRemove = Lists.newArrayList();
493        for (Entry<Range<K>, V> entry : entrySet()) {
494          if (predicate.apply(entry)) {
495            toRemove.add(entry.getKey());
496          }
497        }
498        for (Range<K> range : toRemove) {
499          TreeRangeMap.this.remove(range);
500        }
501        return !toRemove.isEmpty();
502      }
503
504      @Override
505      public Set<Range<K>> keySet() {
506        return new Maps.KeySet<Range<K>, V>(SubRangeMapAsMap.this) {
507          @Override
508          public boolean remove(@Nullable Object o) {
509            return SubRangeMapAsMap.this.remove(o) != null;
510          }
511          
512          @Override
513          public boolean retainAll(Collection<?> c) {
514            return removeEntryIf(compose(not(in(c)), Maps.<Range<K>>keyFunction()));
515          }
516        };
517      }
518
519      @Override
520      public Set<Entry<Range<K>, V>> entrySet() {
521        return new Maps.EntrySet<Range<K>, V>() {
522          @Override
523          Map<Range<K>, V> map() {
524            return SubRangeMapAsMap.this;
525          }
526
527          @Override
528          public Iterator<Entry<Range<K>, V>> iterator() {
529            if (subRange.isEmpty()) {
530              return Iterators.emptyIterator();
531            }
532            Cut<K> cutToStart = Objects.firstNonNull(
533                entriesByLowerBound.floorKey(subRange.lowerBound),
534                subRange.lowerBound);
535            final Iterator<RangeMapEntry<K, V>> backingItr = 
536                entriesByLowerBound.tailMap(cutToStart, true).values().iterator();
537            return new AbstractIterator<Entry<Range<K>, V>>() {
538
539              @Override
540              protected Entry<Range<K>, V> computeNext() {
541                while (backingItr.hasNext()) {
542                  RangeMapEntry<K, V> entry = backingItr.next();
543                  if (entry.getLowerBound().compareTo(subRange.upperBound) >= 0) {
544                    break;
545                  } else if (entry.getUpperBound().compareTo(subRange.lowerBound) > 0) {
546                    // this might not be true e.g. at the start of the iteration
547                    return Maps.immutableEntry(
548                        entry.getKey().intersection(subRange), entry.getValue());
549                  }
550                }
551                return endOfData();
552              }
553            };
554          }
555          
556          @Override
557          public boolean retainAll(Collection<?> c) {
558            return removeEntryIf(not(in(c)));
559          }
560          
561          @Override
562          public int size() {
563            return Iterators.size(iterator());
564          }
565          
566          @Override
567          public boolean isEmpty() {
568            return !iterator().hasNext();
569          }
570        };
571      }
572      
573      @Override
574      public Collection<V> values() {
575        return new Maps.Values<Range<K>, V>(this) {          
576          @Override
577          public boolean removeAll(Collection<?> c) {
578            return removeEntryIf(compose(in(c), Maps.<V>valueFunction()));            
579          }
580          
581          @Override
582          public boolean retainAll(Collection<?> c) {
583            return removeEntryIf(compose(not(in(c)), Maps.<V>valueFunction()));
584          }
585        };
586      }
587    }
588  }
589
590  @Override
591  public boolean equals(@Nullable Object o) {
592    if (o instanceof RangeMap) {
593      RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o;
594      return asMapOfRanges().equals(rangeMap.asMapOfRanges());
595    }
596    return false;
597  }
598
599  @Override
600  public int hashCode() {
601    return asMapOfRanges().hashCode();
602  }
603
604  @Override
605  public String toString() {
606    return entriesByLowerBound.values().toString();
607  }
608}