/*
* 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.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import javax.annotation.Nullable;
/**
* An immutable implementation of {@code RangeMap}, supporting all query operations efficiently.
*
* <p>Like all {@code RangeMap} implementations, this supports neither null keys nor null values.
*
* @author Louis Wasserman
* @since 14.0
*/
@Beta
@GwtIncompatible("NavigableMap")
public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K, V> {
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 ImmutableList<Range<K>> ranges;
private final 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 RegularImmutableSortedMap<Range<K>, V>(rangeSet, values);
}
@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();
}
}