/*
 * Copyright (C) 2007 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 com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import java.util.Spliterator;
import java.util.Spliterators;
import org.checkerframework.checker.nullness.qual.Nullable;

Implementation of ImmutableSet with two or more elements.
Author:Kevin Bourrillion
/** * Implementation of {@link ImmutableSet} with two or more elements. * * @author Kevin Bourrillion */
@GwtCompatible(serializable = true, emulated = true) @SuppressWarnings("serial") // uses writeReplace(), not default serialization final class RegularImmutableSet<E> extends ImmutableSet<E> { static final RegularImmutableSet<Object> EMPTY = new RegularImmutableSet<>(new Object[0], 0, null, 0); private final transient Object[] elements; // the same elements in hashed positions (plus nulls) @VisibleForTesting final transient Object[] table; // 'and' with an int to get a valid table index. private final transient int mask; private final transient int hashCode; RegularImmutableSet(Object[] elements, int hashCode, Object[] table, int mask) { this.elements = elements; this.table = table; this.mask = mask; this.hashCode = hashCode; } @Override public boolean contains(@Nullable Object target) { Object[] table = this.table; if (target == null || table == null) { return false; } for (int i = Hashing.smearedHash(target); ; i++) { i &= mask; Object candidate = table[i]; if (candidate == null) { return false; } else if (candidate.equals(target)) { return true; } } } @Override public int size() { return elements.length; } @Override public UnmodifiableIterator<E> iterator() { return (UnmodifiableIterator<E>) Iterators.forArray(elements); } @Override public Spliterator<E> spliterator() { return Spliterators.spliterator(elements, SPLITERATOR_CHARACTERISTICS); } @Override int copyIntoArray(Object[] dst, int offset) { System.arraycopy(elements, 0, dst, offset, elements.length); return offset + elements.length; } @Override ImmutableList<E> createAsList() { return (table == null) ? ImmutableList.<E>of() : new RegularImmutableAsList<E>(this, elements); } @Override boolean isPartialView() { return false; } @Override public int hashCode() { return hashCode; } @Override boolean isHashCodeFast() { return true; } }