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8166365: Small immutable collections should provide optimized implementations when possible
Reviewed-by: smarks, psandoz, attila
This commit is contained in:
Claes Redestad
parent
186fec9a8a
commit
a004b7fb9e
8 changed files with 228 additions and 42 deletions
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@ -1,5 +1,5 @@
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/*
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* Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@ -35,6 +35,7 @@ import java.util.function.BiFunction;
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import java.util.function.Function;
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import java.util.function.Predicate;
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import java.util.function.UnaryOperator;
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import jdk.internal.vm.annotation.Stable;
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/**
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* Container class for immutable collections. Not part of the public API.
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@ -105,6 +106,11 @@ class ImmutableCollections {
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return null; // but the compiler doesn't know this
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}
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@Override
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public Iterator<E> iterator() {
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return Collections.emptyIterator();
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}
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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throw new InvalidObjectException("not serial proxy");
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}
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@ -112,9 +118,26 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_LIST);
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}
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@Override
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public boolean contains(Object o) {
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Objects.requireNonNull(o);
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return false;
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}
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@Override
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public boolean containsAll(Collection<?> o) {
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return o.isEmpty(); // implicit nullcheck of o
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}
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@Override
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public int hashCode() {
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return 1;
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}
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}
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static final class List1<E> extends AbstractImmutableList<E> {
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@Stable
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private final E e0;
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List1(E e0) {
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@ -129,7 +152,6 @@ class ImmutableCollections {
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@Override
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public E get(int index) {
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Objects.checkIndex(index, 1);
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// assert index == 0
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return e0;
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}
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@ -140,10 +162,22 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_LIST, e0);
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}
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@Override
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public boolean contains(Object o) {
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return o.equals(e0); // implicit nullcheck of o
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}
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@Override
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public int hashCode() {
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return 31 + e0.hashCode();
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}
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}
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static final class List2<E> extends AbstractImmutableList<E> {
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@Stable
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private final E e0;
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@Stable
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private final E e1;
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List2(E e0, E e1) {
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@ -166,6 +200,17 @@ class ImmutableCollections {
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}
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}
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@Override
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public boolean contains(Object o) {
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return o.equals(e0) || o.equals(e1); // implicit nullcheck of o
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}
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@Override
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public int hashCode() {
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int hash = 31 + e0.hashCode();
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return 31 * hash + e1.hashCode();
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}
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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throw new InvalidObjectException("not serial proxy");
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}
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@ -176,6 +221,7 @@ class ImmutableCollections {
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}
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static final class ListN<E> extends AbstractImmutableList<E> {
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@Stable
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private final E[] elements;
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@SafeVarargs
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@ -200,6 +246,25 @@ class ImmutableCollections {
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return elements[index];
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}
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@Override
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public boolean contains(Object o) {
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for (E e : elements) {
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if (o.equals(e)) { // implicit nullcheck of o
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return true;
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}
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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 hashCode() {
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int hash = 1;
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for (E e : elements) {
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hash = 31 * hash + e.hashCode();
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}
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return hash;
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}
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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throw new InvalidObjectException("not serial proxy");
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}
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@ -238,7 +303,13 @@ class ImmutableCollections {
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@Override
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public boolean contains(Object o) {
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return super.contains(Objects.requireNonNull(o));
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Objects.requireNonNull(o);
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return false;
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}
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@Override
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public boolean containsAll(Collection<?> o) {
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return o.isEmpty(); // implicit nullcheck of o
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}
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@Override
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@ -253,9 +324,15 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_SET);
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}
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@Override
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public int hashCode() {
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return 0;
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}
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}
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static final class Set1<E> extends AbstractImmutableSet<E> {
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@Stable
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private final E e0;
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Set1(E e0) {
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@ -269,7 +346,7 @@ class ImmutableCollections {
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@Override
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public boolean contains(Object o) {
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return super.contains(Objects.requireNonNull(o));
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return o.equals(e0); // implicit nullcheck of o
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}
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@Override
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@ -284,17 +361,21 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_SET, e0);
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}
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@Override
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public int hashCode() {
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return e0.hashCode();
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}
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}
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static final class Set2<E> extends AbstractImmutableSet<E> {
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private final E e0;
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private final E e1;
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@Stable
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final E e0;
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@Stable
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final E e1;
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Set2(E e0, E e1) {
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Objects.requireNonNull(e0);
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Objects.requireNonNull(e1);
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if (e0.equals(e1)) {
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if (e0.equals(Objects.requireNonNull(e1))) { // implicit nullcheck of e0
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throw new IllegalArgumentException("duplicate element: " + e0);
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}
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@ -314,7 +395,12 @@ class ImmutableCollections {
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@Override
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public boolean contains(Object o) {
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return super.contains(Objects.requireNonNull(o));
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return o.equals(e0) || o.equals(e1); // implicit nullcheck of o
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}
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@Override
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public int hashCode() {
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return e0.hashCode() + e1.hashCode();
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}
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@Override
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@ -358,8 +444,10 @@ class ImmutableCollections {
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* @param <E> the element type
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*/
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static final class SetN<E> extends AbstractImmutableSet<E> {
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private final E[] elements;
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private final int size;
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@Stable
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final E[] elements;
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@Stable
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final int size;
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@SafeVarargs
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@SuppressWarnings("unchecked")
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@ -368,8 +456,8 @@ class ImmutableCollections {
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elements = (E[])new Object[EXPAND_FACTOR * input.length];
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for (int i = 0; i < input.length; i++) {
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E e = Objects.requireNonNull(input[i]);
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int idx = probe(e);
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E e = input[i];
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int idx = probe(e); // implicit nullcheck of e
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if (idx >= 0) {
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throw new IllegalArgumentException("duplicate element: " + e);
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} else {
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@ -385,8 +473,7 @@ class ImmutableCollections {
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@Override
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public boolean contains(Object o) {
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Objects.requireNonNull(o);
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return probe(o) >= 0;
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return probe(o) >= 0; // implicit nullcheck of o
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}
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@Override
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@ -414,8 +501,21 @@ class ImmutableCollections {
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};
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}
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@Override
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public int hashCode() {
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int h = 0;
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for (E e : elements) {
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if (e != null) {
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h += e.hashCode();
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}
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}
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return h;
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}
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// returns index at which element is present; or if absent,
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// (-i - 1) where i is location where element should be inserted
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// (-i - 1) where i is location where element should be inserted.
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// Callers are relying on this method to perform an implicit nullcheck
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// of pe
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private int probe(Object pe) {
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int idx = Math.floorMod(pe.hashCode() ^ SALT, elements.length);
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while (true) {
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@ -481,12 +581,14 @@ class ImmutableCollections {
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@Override
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public boolean containsKey(Object o) {
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return super.containsKey(Objects.requireNonNull(o));
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Objects.requireNonNull(o);
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return false;
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}
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@Override
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public boolean containsValue(Object o) {
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return super.containsValue(Objects.requireNonNull(o));
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Objects.requireNonNull(o);
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return false;
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}
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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@ -496,10 +598,17 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_MAP);
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}
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@Override
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public int hashCode() {
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return 0;
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}
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}
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static final class Map1<K,V> extends AbstractImmutableMap<K,V> {
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@Stable
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private final K k0;
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@Stable
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private final V v0;
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Map1(K k0, V v0) {
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@ -514,12 +623,12 @@ class ImmutableCollections {
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@Override
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public boolean containsKey(Object o) {
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return super.containsKey(Objects.requireNonNull(o));
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return o.equals(k0); // implicit nullcheck of o
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}
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@Override
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public boolean containsValue(Object o) {
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return super.containsValue(Objects.requireNonNull(o));
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return o.equals(v0); // implicit nullcheck of o
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}
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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@ -529,6 +638,11 @@ class ImmutableCollections {
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private Object writeReplace() {
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return new CollSer(CollSer.IMM_MAP, k0, v0);
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}
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@Override
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public int hashCode() {
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return k0.hashCode() ^ v0.hashCode();
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}
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}
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/**
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@ -541,12 +655,13 @@ class ImmutableCollections {
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* @param <V> the value type
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*/
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static final class MapN<K,V> extends AbstractImmutableMap<K,V> {
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private final Object[] table; // pairs of key, value
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private final int size; // number of pairs
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@Stable
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final Object[] table; // pairs of key, value
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@Stable
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final int size; // number of pairs
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MapN(Object... input) {
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Objects.requireNonNull(input);
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if ((input.length & 1) != 0) {
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if ((input.length & 1) != 0) { // implicit nullcheck of input
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throw new InternalError("length is odd");
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}
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size = input.length >> 1;
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@ -573,12 +688,30 @@ class ImmutableCollections {
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@Override
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public boolean containsKey(Object o) {
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return probe(Objects.requireNonNull(o)) >= 0;
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return probe(o) >= 0; // implicit nullcheck of o
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}
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@Override
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public boolean containsValue(Object o) {
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return super.containsValue(Objects.requireNonNull(o));
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for (int i = 1; i < table.length; i += 2) {
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Object v = table[i];
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if (v != null && o.equals(v)) { // implicit nullcheck of o
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return true;
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}
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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 hashCode() {
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int hash = 0;
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for (int i = 0; i < table.length; i += 2) {
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Object k = table[i];
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if (k != null) {
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hash += k.hashCode() ^ table[i + 1].hashCode();
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}
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}
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return hash;
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}
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@Override
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@ -638,7 +771,9 @@ class ImmutableCollections {
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}
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// returns index at which the probe key is present; or if absent,
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// (-i - 1) where i is location where element should be inserted
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// (-i - 1) where i is location where element should be inserted.
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// Callers are relying on this method to perform an implicit nullcheck
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// of pk.
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private int probe(Object pk) {
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int idx = Math.floorMod(pk.hashCode() ^ SALT, table.length >> 1) << 1;
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while (true) {
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