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8215995: Add specialized toArray methods to immutable collections

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Reviewed-by: martin, smarks
This commit is contained in:
Claes Redestad 2019-01-09 01:06:19 +01:00
parent ffb08ea636
commit 68884330e1
2 changed files with 389 additions and 4 deletions
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136
src/java.base/share/classes/java/util/ImmutableCollections.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -31,6 +31,7 @@ import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.function.Predicate;
@ -357,6 +358,30 @@ class ImmutableCollections {
throw outOfBounds(index);
}
}
@Override
public Object[] toArray() {
Object[] array = new Object[size];
for (int i = 0; i < size; i++) {
array[i] = get(i);
}
return array;
}
@Override
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
T[] array = a.length >= size ? a :
(T[])java.lang.reflect.Array
.newInstance(a.getClass().getComponentType(), size);
for (int i = 0; i < size; i++) {
array[i] = (T)get(i);
}
if (array.length > size) {
array[size] = null; // null-terminate
}
return array;
}
}
static final class List12<E> extends AbstractImmutableList<E>
@ -405,6 +430,30 @@ class ImmutableCollections {
}
}
@Override
public Object[] toArray() {
if (e1 == null) {
return new Object[] { e0 };
} else {
return new Object[] { e0, e1 };
}
}
@Override
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
int size = e1 == null ? 1 : 2;
T[] array = a.length >= size ? a :
(T[])Array.newInstance(a.getClass().getComponentType(), size);
array[0] = (T)e0;
if (size == 2) {
array[1] = (T)e1;
}
if (array.length > size) {
array[size] = null; // null-terminate
}
return array;
}
}
static final class ListN<E> extends AbstractImmutableList<E>
@ -456,6 +505,26 @@ class ImmutableCollections {
private Object writeReplace() {
return new CollSer(CollSer.IMM_LIST, elements);
}
@Override
public Object[] toArray() {
return Arrays.copyOf(elements, elements.length);
}
@Override
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
int size = elements.length;
if (a.length < size) {
// Make a new array of a's runtime type, but my contents:
return (T[]) Arrays.copyOf(elements, size, a.getClass());
}
System.arraycopy(elements, 0, a, 0, size);
if (a.length > size) {
a[size] = null; // null-terminate
}
return a;
}
}
// ---------- Set Implementations ----------
@ -565,8 +634,41 @@ class ImmutableCollections {
return new CollSer(CollSer.IMM_SET, e0, e1);
}
}
@Override
public Object[] toArray() {
if (e1 == null) {
return new Object[] { e0 };
} else if (SALT >= 0) {
return new Object[] { e1, e0 };
} else {
return new Object[] { e0, e1 };
}
}
@Override
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
int size = e1 == null ? 1 : 2;
T[] array = a.length >= size ? a :
(T[])Array.newInstance(a.getClass().getComponentType(), size);
if (size == 1) {
array[0] = (T)e0;
} else if (SALT >= 0) {
array[0] = (T)e1;
array[1] = (T)e0;
} else {
array[0] = (T)e0;
array[1] = (T)e1;
}
if (array.length > size) {
array[size] = null; // null-terminate
}
return array;
}
}
/**
* An array-based Set implementation. The element array must be strictly
* larger than the size (the number of contained elements) so that at
@ -653,7 +755,7 @@ class ImmutableCollections {
@Override
public E next() {
if (hasNext()) {
if (remaining > 0) {
E element;
// skip null elements
while ((element = elements[nextIndex()]) == null) {}
@ -713,6 +815,31 @@ class ImmutableCollections {
}
return new CollSer(CollSer.IMM_SET, array);
}
@Override
public Object[] toArray() {
Object[] array = new Object[size];
Iterator<E> it = iterator();
for (int i = 0; i < size; i++) {
array[i] = it.next();
}
return array;
}
@Override
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
T[] array = a.length >= size ? a :
(T[])Array.newInstance(a.getClass().getComponentType(), size);
Iterator<E> it = iterator();
for (int i = 0; i < size; i++) {
array[i] = (T)it.next();
}
if (array.length > size) {
array[size] = null; // null-terminate
}
return array;
}
}
// ---------- Map Implementations ----------
@ -915,8 +1042,9 @@ class ImmutableCollections {
@Override
public Map.Entry<K,V> next() {
if (hasNext()) {
while (table[nextIndex()] == null) {}
if (remaining > 0) {
int idx;
while (table[idx = nextIndex()] == null) {}
@SuppressWarnings("unchecked")
Map.Entry<K,V> e =
new KeyValueHolder<>((K)table[idx], (V)table[idx+1]);