528 lines
17 KiB
Java
528 lines
17 KiB
Java
/*
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* Copyright (C) 2009 The Guava Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.common.collect;
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import static com.google.common.base.Objects.firstNonNull;
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import static com.google.common.base.Preconditions.checkNotNull;
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import static java.util.Arrays.asList;
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import java.io.IOException;
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import java.io.InvalidObjectException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.Comparator;
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import java.util.LinkedHashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Map.Entry;
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import javax.annotation.Nullable;
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import com.google.common.annotations.GwtCompatible;
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import com.google.common.annotations.GwtIncompatible;
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/**
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* An immutable {@link SetMultimap} with reliable user-specified key and value
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* iteration order. Does not permit null keys or values.
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*
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* <p>
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* Unlike {@link Multimaps#unmodifiableSetMultimap(SetMultimap)}, which is a
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* <i>view</i> of a separate multimap which can still change, an instance of
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* {@code ImmutableSetMultimap} contains its own data and will <i>never</i>
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* change. {@code ImmutableSetMultimap} is convenient for
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* {@code public static final} multimaps ("constant multimaps") and also lets
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* you easily make a "defensive copy" of a multimap provided to your class by a
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* caller.
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*
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* <p>
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* <b>Note:</b> Although this class is not final, it cannot be subclassed as it
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* has no public or protected constructors. Thus, instances of this class are
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* guaranteed to be immutable.
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*
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* <p>
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* See the Guava User Guide article on <a href=
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* "http://code.google.com/p/guava-libraries/wiki/ImmutableCollectionsExplained">
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* immutable collections</a>.
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*
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* @author Mike Ward
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* @since 2.0 (imported from Google Collections Library)
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*/
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@GwtCompatible(serializable = true, emulated = true)
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public class ImmutableSetMultimap<K, V> extends ImmutableMultimap<K, V> implements SetMultimap<K, V> {
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/** Returns the empty multimap. */
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// Casting is safe because the multimap will never hold any elements.
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@SuppressWarnings("unchecked")
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public static <K, V> ImmutableSetMultimap<K, V> of() {
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return (ImmutableSetMultimap<K, V>) EmptyImmutableSetMultimap.INSTANCE;
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}
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/**
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* Returns an immutable multimap containing a single entry.
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*/
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public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1) {
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ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
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builder.put(k1, v1);
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return builder.build();
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}
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/**
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* Returns an immutable multimap containing the given entries, in order.
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* Repeated occurrences of an entry (according to {@link Object#equals}) after
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* the first are ignored.
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*/
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public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2) {
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ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
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builder.put(k1, v1);
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builder.put(k2, v2);
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return builder.build();
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}
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/**
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* Returns an immutable multimap containing the given entries, in order.
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* Repeated occurrences of an entry (according to {@link Object#equals}) after
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* the first are ignored.
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*/
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public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
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ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
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builder.put(k1, v1);
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builder.put(k2, v2);
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builder.put(k3, v3);
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return builder.build();
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}
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/**
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* Returns an immutable multimap containing the given entries, in order.
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* Repeated occurrences of an entry (according to {@link Object#equals}) after
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* the first are ignored.
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*/
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public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
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ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
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builder.put(k1, v1);
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builder.put(k2, v2);
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builder.put(k3, v3);
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builder.put(k4, v4);
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return builder.build();
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}
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/**
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* Returns an immutable multimap containing the given entries, in order.
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* Repeated occurrences of an entry (according to {@link Object#equals}) after
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* the first are ignored.
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*/
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public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
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ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
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builder.put(k1, v1);
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builder.put(k2, v2);
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builder.put(k3, v3);
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builder.put(k4, v4);
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builder.put(k5, v5);
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return builder.build();
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}
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// looking for of() with > 5 entries? Use the builder instead.
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/**
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* Returns a new {@link Builder}.
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*/
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public static <K, V> Builder<K, V> builder() {
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return new Builder<K, V>();
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}
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/**
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* Multimap for {@link ImmutableSetMultimap.Builder} that maintains key and
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* value orderings and performs better than {@link LinkedHashMultimap}.
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*/
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private static class BuilderMultimap<K, V> extends AbstractMapBasedMultimap<K, V> {
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BuilderMultimap() {
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super(new LinkedHashMap<K, Collection<V>>());
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}
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@Override
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Collection<V> createCollection() {
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return Sets.newLinkedHashSet();
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}
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private static final long serialVersionUID = 0;
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}
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/**
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* A builder for creating immutable {@code SetMultimap} instances, especially
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* {@code public static final} multimaps ("constant multimaps"). Example:
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*
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* <pre>
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* {
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* @code
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*
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* static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP = new ImmutableSetMultimap.Builder<String, Integer>()
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* .put("one", 1).putAll("several", 1, 2, 3).putAll("many", 1, 2, 3, 4, 5).build();
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* }
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* </pre>
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*
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* <p>
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* Builder instances can be reused; it is safe to call {@link #build} multiple
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* times to build multiple multimaps in series. Each multimap contains the
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* key-value mappings in the previously created multimaps.
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*
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* @since 2.0 (imported from Google Collections Library)
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*/
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public static final class Builder<K, V> extends ImmutableMultimap.Builder<K, V> {
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/**
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* Creates a new builder. The returned builder is equivalent to the builder
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* generated by {@link ImmutableSetMultimap#builder}.
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*/
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public Builder() {
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builderMultimap = new BuilderMultimap<K, V>();
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}
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/**
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* Adds a key-value mapping to the built multimap if it is not already present.
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*/
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@Override
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public Builder<K, V> put(K key, V value) {
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builderMultimap.put(checkNotNull(key), checkNotNull(value));
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return this;
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}
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/**
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* Adds an entry to the built multimap if it is not already present.
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*
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* @since 11.0
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*/
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@Override
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public Builder<K, V> put(Entry<? extends K, ? extends V> entry) {
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builderMultimap.put(checkNotNull(entry.getKey()), checkNotNull(entry.getValue()));
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return this;
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}
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@Override
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public Builder<K, V> putAll(K key, Iterable<? extends V> values) {
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Collection<V> collection = builderMultimap.get(checkNotNull(key));
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for (V value : values) {
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collection.add(checkNotNull(value));
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}
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return this;
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}
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@Override
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public Builder<K, V> putAll(K key, V... values) {
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return putAll(key, Arrays.asList(values));
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}
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@Override
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public Builder<K, V> putAll(Multimap<? extends K, ? extends V> multimap) {
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for (Entry<? extends K, ? extends Collection<? extends V>> entry : multimap.asMap().entrySet()) {
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putAll(entry.getKey(), entry.getValue());
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}
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return this;
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}
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/**
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* {@inheritDoc}
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*
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* @since 8.0
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*/
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@Override
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public Builder<K, V> orderKeysBy(Comparator<? super K> keyComparator) {
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this.keyComparator = checkNotNull(keyComparator);
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return this;
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}
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/**
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* Specifies the ordering of the generated multimap's values for each key.
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*
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* <p>
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* If this method is called, the sets returned by the {@code get()} method of
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* the generated multimap and its {@link Multimap#asMap()} view are
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* {@link ImmutableSortedSet} instances. However, serialization does not
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* preserve that property, though it does maintain the key and value ordering.
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*
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* @since 8.0
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*/
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// TODO: Make serialization behavior consistent.
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@Override
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public Builder<K, V> orderValuesBy(Comparator<? super V> valueComparator) {
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super.orderValuesBy(valueComparator);
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return this;
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}
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/**
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* Returns a newly-created immutable set multimap.
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*/
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@Override
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public ImmutableSetMultimap<K, V> build() {
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if (keyComparator != null) {
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Multimap<K, V> sortedCopy = new BuilderMultimap<K, V>();
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List<Map.Entry<K, Collection<V>>> entries = Lists.newArrayList(builderMultimap.asMap().entrySet());
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Collections.sort(entries, Ordering.from(keyComparator).<K>onKeys());
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for (Map.Entry<K, Collection<V>> entry : entries) {
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sortedCopy.putAll(entry.getKey(), entry.getValue());
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}
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builderMultimap = sortedCopy;
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}
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return copyOf(builderMultimap, valueComparator);
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}
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}
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/**
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* Returns an immutable set multimap containing the same mappings as
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* {@code multimap}. The generated multimap's key and value orderings correspond
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* to the iteration ordering of the {@code multimap.asMap()} view. Repeated
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* occurrences of an entry in the multimap after the first are ignored.
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*
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* <p>
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* Despite the method name, this method attempts to avoid actually copying the
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* data when it is safe to do so. The exact circumstances under which a copy
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* will or will not be performed are undocumented and subject to change.
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*
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* @throws NullPointerException if any key or value in {@code multimap} is null
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*/
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public static <K, V> ImmutableSetMultimap<K, V> copyOf(Multimap<? extends K, ? extends V> multimap) {
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return copyOf(multimap, null);
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}
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private static <K, V> ImmutableSetMultimap<K, V> copyOf(Multimap<? extends K, ? extends V> multimap,
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Comparator<? super V> valueComparator) {
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checkNotNull(multimap); // eager for GWT
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if (multimap.isEmpty() && valueComparator == null) {
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return of();
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}
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if (multimap instanceof ImmutableSetMultimap) {
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@SuppressWarnings("unchecked") // safe since multimap is not writable
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ImmutableSetMultimap<K, V> kvMultimap = (ImmutableSetMultimap<K, V>) multimap;
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if (!kvMultimap.isPartialView()) {
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return kvMultimap;
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}
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}
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ImmutableMap.Builder<K, ImmutableSet<V>> builder = ImmutableMap.builder();
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int size = 0;
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for (Entry<? extends K, ? extends Collection<? extends V>> entry : multimap.asMap().entrySet()) {
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K key = entry.getKey();
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Collection<? extends V> values = entry.getValue();
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ImmutableSet<V> set = valueSet(valueComparator, values);
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if (!set.isEmpty()) {
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builder.put(key, set);
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size += set.size();
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}
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}
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return new ImmutableSetMultimap<K, V>(builder.build(), size, valueComparator);
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}
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/**
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* Returned by get() when a missing key is provided. Also holds the comparator,
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* if any, used for values.
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*/
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private final transient ImmutableSet<V> emptySet;
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ImmutableSetMultimap(ImmutableMap<K, ImmutableSet<V>> map, int size,
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@Nullable Comparator<? super V> valueComparator) {
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super(map, size);
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this.emptySet = emptySet(valueComparator);
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}
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// views
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/**
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* Returns an immutable set of the values for the given key. If no mappings in
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* the multimap have the provided key, an empty immutable set is returned. The
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* values are in the same order as the parameters used to build this multimap.
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*/
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@Override
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public ImmutableSet<V> get(@Nullable K key) {
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// This cast is safe as its type is known in constructor.
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ImmutableSet<V> set = (ImmutableSet<V>) map.get(key);
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return firstNonNull(set, emptySet);
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}
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private transient ImmutableSetMultimap<V, K> inverse;
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/**
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* {@inheritDoc}
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*
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* <p>
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* Because an inverse of a set multimap cannot contain multiple pairs with the
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* same key and value, this method returns an {@code ImmutableSetMultimap}
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* rather than the {@code ImmutableMultimap} specified in the {@code
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* ImmutableMultimap} class.
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*
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* @since 11.0
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*/
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public ImmutableSetMultimap<V, K> inverse() {
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ImmutableSetMultimap<V, K> result = inverse;
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return (result == null) ? (inverse = invert()) : result;
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}
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private ImmutableSetMultimap<V, K> invert() {
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Builder<V, K> builder = builder();
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for (Entry<K, V> entry : entries()) {
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builder.put(entry.getValue(), entry.getKey());
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}
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ImmutableSetMultimap<V, K> invertedMultimap = builder.build();
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invertedMultimap.inverse = this;
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return invertedMultimap;
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}
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/**
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* Guaranteed to throw an exception and leave the multimap unmodified.
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*
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* @throws UnsupportedOperationException always
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* @deprecated Unsupported operation.
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*/
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@Deprecated
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@Override
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public ImmutableSet<V> removeAll(Object key) {
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throw new UnsupportedOperationException();
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}
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/**
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* Guaranteed to throw an exception and leave the multimap unmodified.
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*
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* @throws UnsupportedOperationException always
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* @deprecated Unsupported operation.
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*/
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@Deprecated
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@Override
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public ImmutableSet<V> replaceValues(K key, Iterable<? extends V> values) {
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throw new UnsupportedOperationException();
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}
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private transient ImmutableSet<Entry<K, V>> entries;
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/**
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* Returns an immutable collection of all key-value pairs in the multimap. Its
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* iterator traverses the values for the first key, the values for the second
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* key, and so on.
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*/
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@Override
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public ImmutableSet<Entry<K, V>> entries() {
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ImmutableSet<Entry<K, V>> result = entries;
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return (result == null) ? (entries = new EntrySet<K, V>(this)) : result;
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}
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private static final class EntrySet<K, V> extends ImmutableSet<Entry<K, V>> {
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private transient final ImmutableSetMultimap<K, V> multimap;
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EntrySet(ImmutableSetMultimap<K, V> multimap) {
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this.multimap = multimap;
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}
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@Override
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public boolean contains(@Nullable Object object) {
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if (object instanceof Entry) {
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Entry<?, ?> entry = (Entry<?, ?>) object;
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return multimap.containsEntry(entry.getKey(), entry.getValue());
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}
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return false;
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}
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@Override
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public int size() {
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return multimap.size();
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}
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@Override
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public UnmodifiableIterator<Entry<K, V>> iterator() {
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return multimap.entryIterator();
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}
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@Override
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boolean isPartialView() {
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return false;
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}
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}
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private static <V> ImmutableSet<V> valueSet(@Nullable Comparator<? super V> valueComparator,
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Collection<? extends V> values) {
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return (valueComparator == null) ? ImmutableSet.copyOf(values)
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: ImmutableSortedSet.copyOf(valueComparator, values);
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}
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private static <V> ImmutableSet<V> emptySet(@Nullable Comparator<? super V> valueComparator) {
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return (valueComparator == null) ? ImmutableSet.<V>of() : ImmutableSortedSet.<V>emptySet(valueComparator);
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}
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/**
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* @serialData number of distinct keys, and then for each distinct key: the key,
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* the number of values for that key, and the key's values
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*/
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@GwtIncompatible("java.io.ObjectOutputStream")
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private void writeObject(ObjectOutputStream stream) throws IOException {
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stream.defaultWriteObject();
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stream.writeObject(valueComparator());
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Serialization.writeMultimap(this, stream);
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}
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@Nullable
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Comparator<? super V> valueComparator() {
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return emptySet instanceof ImmutableSortedSet ? ((ImmutableSortedSet<V>) emptySet).comparator() : null;
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}
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@GwtIncompatible("java.io.ObjectInputStream")
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// Serialization type safety is at the caller's mercy.
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@SuppressWarnings("unchecked")
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private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
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stream.defaultReadObject();
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Comparator<Object> valueComparator = (Comparator<Object>) stream.readObject();
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int keyCount = stream.readInt();
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if (keyCount < 0) {
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throw new InvalidObjectException("Invalid key count " + keyCount);
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}
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ImmutableMap.Builder<Object, ImmutableSet<Object>> builder = ImmutableMap.builder();
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int tmpSize = 0;
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for (int i = 0; i < keyCount; i++) {
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Object key = stream.readObject();
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int valueCount = stream.readInt();
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if (valueCount <= 0) {
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throw new InvalidObjectException("Invalid value count " + valueCount);
|
|
}
|
|
|
|
Object[] array = new Object[valueCount];
|
|
for (int j = 0; j < valueCount; j++) {
|
|
array[j] = stream.readObject();
|
|
}
|
|
ImmutableSet<Object> valueSet = valueSet(valueComparator, asList(array));
|
|
if (valueSet.size() != array.length) {
|
|
throw new InvalidObjectException("Duplicate key-value pairs exist for key " + key);
|
|
}
|
|
builder.put(key, valueSet);
|
|
tmpSize += valueCount;
|
|
}
|
|
|
|
ImmutableMap<Object, ImmutableSet<Object>> tmpMap;
|
|
try {
|
|
tmpMap = builder.build();
|
|
} catch (IllegalArgumentException e) {
|
|
throw (InvalidObjectException) new InvalidObjectException(e.getMessage()).initCause(e);
|
|
}
|
|
|
|
FieldSettersHolder.MAP_FIELD_SETTER.set(this, tmpMap);
|
|
FieldSettersHolder.SIZE_FIELD_SETTER.set(this, tmpSize);
|
|
FieldSettersHolder.EMPTY_SET_FIELD_SETTER.set(this, emptySet(valueComparator));
|
|
}
|
|
|
|
@GwtIncompatible("not needed in emulated source.")
|
|
private static final long serialVersionUID = 0;
|
|
}
|