com.google.common.collect.CollectCollectors Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* Copyright (C) 2016 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.checkNotNull;
import static java.util.Collections.singletonMap;
import static java.util.stream.Collectors.collectingAndThen;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Preconditions;
import java.util.Collection;
import java.util.Comparator;
import java.util.EnumMap;
import java.util.EnumSet;
import java.util.LinkedHashMap;
import java.util.TreeMap;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.function.ToIntFunction;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/** Collectors utilities for {@code common.collect} internals. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class CollectCollectors {
private static final Collector> TO_IMMUTABLE_LIST =
Collector.of(
ImmutableList::builder,
ImmutableList.Builder::add,
ImmutableList.Builder::combine,
ImmutableList.Builder::build);
private static final Collector> TO_IMMUTABLE_SET =
Collector.of(
ImmutableSet::builder,
ImmutableSet.Builder::add,
ImmutableSet.Builder::combine,
ImmutableSet.Builder::build);
@GwtIncompatible
private static final Collector>, ?, ImmutableRangeSet>>
TO_IMMUTABLE_RANGE_SET =
Collector.of(
ImmutableRangeSet::builder,
ImmutableRangeSet.Builder::add,
ImmutableRangeSet.Builder::combine,
ImmutableRangeSet.Builder::build);
// Lists
@SuppressWarnings({"rawtypes", "unchecked"})
static Collector> toImmutableList() {
return (Collector) TO_IMMUTABLE_LIST;
}
// Sets
@SuppressWarnings({"rawtypes", "unchecked"})
static Collector> toImmutableSet() {
return (Collector) TO_IMMUTABLE_SET;
}
static Collector> toImmutableSortedSet(
Comparator comparator) {
checkNotNull(comparator);
return Collector.of(
() -> new ImmutableSortedSet.Builder(comparator),
ImmutableSortedSet.Builder::add,
ImmutableSortedSet.Builder::combine,
ImmutableSortedSet.Builder::build);
}
@SuppressWarnings({"rawtypes", "unchecked"})
static > Collector> toImmutableEnumSet() {
return (Collector) EnumSetAccumulator.TO_IMMUTABLE_ENUM_SET;
}
private static >
Collector, ImmutableSet> toImmutableEnumSetGeneric() {
return Collector.of(
EnumSetAccumulator::new,
EnumSetAccumulator::add,
EnumSetAccumulator::combine,
EnumSetAccumulator::toImmutableSet,
Collector.Characteristics.UNORDERED);
}
private static final class EnumSetAccumulator> {
@SuppressWarnings({"rawtypes", "unchecked"})
static final Collector, ?, ImmutableSet>> TO_IMMUTABLE_ENUM_SET =
(Collector) toImmutableEnumSetGeneric();
@CheckForNull private EnumSet set;
void add(E e) {
if (set == null) {
set = EnumSet.of(e);
} else {
set.add(e);
}
}
EnumSetAccumulator combine(EnumSetAccumulator other) {
if (this.set == null) {
return other;
} else if (other.set == null) {
return this;
} else {
this.set.addAll(other.set);
return this;
}
}
ImmutableSet toImmutableSet() {
if (set == null) {
return ImmutableSet.of();
}
ImmutableSet ret = ImmutableEnumSet.asImmutable(set);
set = null; // subsequent manual manipulation of the accumulator mustn't affect ret
return ret;
}
}
@GwtIncompatible
@SuppressWarnings({"rawtypes", "unchecked"})
static >
Collector, ?, ImmutableRangeSet> toImmutableRangeSet() {
return (Collector) TO_IMMUTABLE_RANGE_SET;
}
// Multisets
static Collector> toImmutableMultiset(
Function elementFunction, ToIntFunction countFunction) {
checkNotNull(elementFunction);
checkNotNull(countFunction);
return Collector.of(
LinkedHashMultiset::create,
(multiset, t) ->
multiset.add(checkNotNull(elementFunction.apply(t)), countFunction.applyAsInt(t)),
(multiset1, multiset2) -> {
multiset1.addAll(multiset2);
return multiset1;
},
(Multiset multiset) -> ImmutableMultiset.copyFromEntries(multiset.entrySet()));
}
static >
Collector toMultiset(
Function elementFunction,
ToIntFunction countFunction,
Supplier multisetSupplier) {
checkNotNull(elementFunction);
checkNotNull(countFunction);
checkNotNull(multisetSupplier);
return Collector.of(
multisetSupplier,
(ms, t) -> ms.add(elementFunction.apply(t), countFunction.applyAsInt(t)),
(ms1, ms2) -> {
ms1.addAll(ms2);
return ms1;
});
}
// Maps
static Collector> toImmutableMap(
Function keyFunction,
Function valueFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
return Collector.of(
ImmutableMap.Builder::new,
(builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
ImmutableMap.Builder::combine,
ImmutableMap.Builder::buildOrThrow);
}
static Collector> toImmutableMap(
Function keyFunction,
Function valueFunction,
BinaryOperator mergeFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
checkNotNull(mergeFunction);
return collectingAndThen(
Collectors.toMap(keyFunction, valueFunction, mergeFunction, LinkedHashMap::new),
ImmutableMap::copyOf);
}
static
Collector> toImmutableSortedMap(
Comparator comparator,
Function keyFunction,
Function valueFunction) {
checkNotNull(comparator);
checkNotNull(keyFunction);
checkNotNull(valueFunction);
/*
* We will always fail if there are duplicate keys, and the keys are always sorted by
* the Comparator, so the entries can come in an arbitrary order -- so we report UNORDERED.
*/
return Collector.of(
() -> new ImmutableSortedMap.Builder(comparator),
(builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
ImmutableSortedMap.Builder::combine,
ImmutableSortedMap.Builder::buildOrThrow,
Collector.Characteristics.UNORDERED);
}
static
Collector> toImmutableSortedMap(
Comparator comparator,
Function keyFunction,
Function valueFunction,
BinaryOperator mergeFunction) {
checkNotNull(comparator);
checkNotNull(keyFunction);
checkNotNull(valueFunction);
checkNotNull(mergeFunction);
return collectingAndThen(
Collectors.toMap(
keyFunction, valueFunction, mergeFunction, () -> new TreeMap(comparator)),
ImmutableSortedMap::copyOfSorted);
}
static Collector> toImmutableBiMap(
Function keyFunction,
Function valueFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
return Collector.of(
ImmutableBiMap.Builder::new,
(builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
ImmutableBiMap.Builder::combine,
ImmutableBiMap.Builder::buildOrThrow,
new Collector.Characteristics[0]);
}
@J2ktIncompatible
static , V>
Collector> toImmutableEnumMap(
Function keyFunction,
Function valueFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
return Collector.of(
() ->
new EnumMapAccumulator(
(v1, v2) -> {
throw new IllegalArgumentException("Multiple values for key: " + v1 + ", " + v2);
}),
(accum, t) -> {
/*
* We assign these to variables before calling checkNotNull to work around a bug in our
* nullness checker.
*/
K key = keyFunction.apply(t);
V newValue = valueFunction.apply(t);
accum.put(
checkNotNull(key, "Null key for input %s", t),
checkNotNull(newValue, "Null value for input %s", t));
},
EnumMapAccumulator::combine,
EnumMapAccumulator::toImmutableMap,
Collector.Characteristics.UNORDERED);
}
@J2ktIncompatible
static , V>
Collector> toImmutableEnumMap(
Function keyFunction,
Function valueFunction,
BinaryOperator mergeFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
checkNotNull(mergeFunction);
// not UNORDERED because we don't know if mergeFunction is commutative
return Collector.of(
() -> new EnumMapAccumulator(mergeFunction),
(accum, t) -> {
/*
* We assign these to variables before calling checkNotNull to work around a bug in our
* nullness checker.
*/
K key = keyFunction.apply(t);
V newValue = valueFunction.apply(t);
accum.put(
checkNotNull(key, "Null key for input %s", t),
checkNotNull(newValue, "Null value for input %s", t));
},
EnumMapAccumulator::combine,
EnumMapAccumulator::toImmutableMap);
}
@J2ktIncompatible
private static class EnumMapAccumulator, V> {
private final BinaryOperator mergeFunction;
@CheckForNull private EnumMap map = null;
EnumMapAccumulator(BinaryOperator mergeFunction) {
this.mergeFunction = mergeFunction;
}
void put(K key, V value) {
if (map == null) {
map = new EnumMap<>(singletonMap(key, value));
} else {
map.merge(key, value, mergeFunction);
}
}
EnumMapAccumulator combine(EnumMapAccumulator other) {
if (this.map == null) {
return other;
} else if (other.map == null) {
return this;
} else {
other.map.forEach(this::put);
return this;
}
}
ImmutableMap toImmutableMap() {
return (map == null) ? ImmutableMap.of() : ImmutableEnumMap.asImmutable(map);
}
}
@GwtIncompatible
static , V>
Collector> toImmutableRangeMap(
Function> keyFunction,
Function valueFunction) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
return Collector.of(
ImmutableRangeMap::builder,
(builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
ImmutableRangeMap.Builder::combine,
ImmutableRangeMap.Builder::build);
}
// Multimaps
static
Collector> toImmutableListMultimap(
Function keyFunction,
Function valueFunction) {
checkNotNull(keyFunction, "keyFunction");
checkNotNull(valueFunction, "valueFunction");
return Collector.of(
ImmutableListMultimap::builder,
(builder, t) -> builder.put(keyFunction.apply(t), valueFunction.apply(t)),
ImmutableListMultimap.Builder::combine,
ImmutableListMultimap.Builder::build);
}
static
Collector> flatteningToImmutableListMultimap(
Function keyFunction,
Function> valuesFunction) {
checkNotNull(keyFunction);
checkNotNull(valuesFunction);
return collectingAndThen(
flatteningToMultimap(
input -> checkNotNull(keyFunction.apply(input)),
input -> valuesFunction.apply(input).peek(Preconditions::checkNotNull),
MultimapBuilder.linkedHashKeys().arrayListValues()::build),
ImmutableListMultimap::copyOf);
}
static
Collector> toImmutableSetMultimap(
Function keyFunction,
Function valueFunction) {
checkNotNull(keyFunction, "keyFunction");
checkNotNull(valueFunction, "valueFunction");
return Collector.of(
ImmutableSetMultimap::builder,
(builder, t) -> builder.put(keyFunction.apply(t), valueFunction.apply(t)),
ImmutableSetMultimap.Builder::combine,
ImmutableSetMultimap.Builder::build);
}
static
Collector> flatteningToImmutableSetMultimap(
Function keyFunction,
Function> valuesFunction) {
checkNotNull(keyFunction);
checkNotNull(valuesFunction);
return collectingAndThen(
flatteningToMultimap(
input -> checkNotNull(keyFunction.apply(input)),
input -> valuesFunction.apply(input).peek(Preconditions::checkNotNull),
MultimapBuilder.linkedHashKeys().linkedHashSetValues()::build),
ImmutableSetMultimap::copyOf);
}
static <
T extends @Nullable Object,
K extends @Nullable Object,
V extends @Nullable Object,
M extends Multimap>
Collector toMultimap(
Function keyFunction,
Function valueFunction,
Supplier multimapSupplier) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
checkNotNull(multimapSupplier);
return Collector.of(
multimapSupplier,
(multimap, input) -> multimap.put(keyFunction.apply(input), valueFunction.apply(input)),
(multimap1, multimap2) -> {
multimap1.putAll(multimap2);
return multimap1;
});
}
static <
T extends @Nullable Object,
K extends @Nullable Object,
V extends @Nullable Object,
M extends Multimap>
Collector flatteningToMultimap(
Function keyFunction,
Function> valueFunction,
Supplier multimapSupplier) {
checkNotNull(keyFunction);
checkNotNull(valueFunction);
checkNotNull(multimapSupplier);
return Collector.of(
multimapSupplier,
(multimap, input) -> {
K key = keyFunction.apply(input);
Collection valuesForKey = multimap.get(key);
valueFunction.apply(input).forEachOrdered(valuesForKey::add);
},
(multimap1, multimap2) -> {
multimap1.putAll(multimap2);
return multimap1;
});
}
private CollectCollectors() {}
}