зеркало из https://github.com/mono/ikvm-fork.git
239 строки
6.6 KiB
Java
239 строки
6.6 KiB
Java
/*
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* Written by Doug Lea with assistance from members of JCP JSR-166
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* Expert Group and released to the public domain, as explained at
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* http://creativecommons.org/licenses/publicdomain
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*
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* Modified for IKVM.NET by Jeroen Frijters
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*/
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/*
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Parts Copyright (C) 2006 Jeroen Frijters
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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Jeroen Frijters
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jeroen@frijters.net
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*/
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package java.util.concurrent.atomic;
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import java.util.*;
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/**
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* A <tt>long</tt> array in which elements may be updated atomically.
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* See the {@link java.util.concurrent.atomic} package specification
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* for description of the properties of atomic variables.
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* @since 1.5
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* @author Doug Lea
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*/
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public class AtomicLongArray implements java.io.Serializable {
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private static final long serialVersionUID = -2308431214976778248L;
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private final long[] array;
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/**
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* Creates a new AtomicLongArray of given length.
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*
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* @param length the length of the array
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*/
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public AtomicLongArray(int length) {
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array = new long[length];
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}
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/**
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* Creates a new AtomicLongArray with the same length as, and
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* all elements copied from, the given array.
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*
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* @param array the array to copy elements from
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* @throws NullPointerException if array is null
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*/
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public AtomicLongArray(long[] array) {
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if (array == null)
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throw new NullPointerException();
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int length = array.length;
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this.array = new long[length];
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synchronized (this) {
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for (int i = 0; i < array.length; i++)
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this.array[i] = array[i];
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}
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}
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/**
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* Returns the length of the array.
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*
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* @return the length of the array
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*/
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public final int length() {
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return array.length;
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}
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/**
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* Gets the current value at position <tt>i</tt>.
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*
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* @param i the index
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* @return the current value
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*/
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public final synchronized long get(int i) {
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return array[i];
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}
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/**
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* Sets the element at position <tt>i</tt> to the given value.
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*
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* @param i the index
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* @param newValue the new value
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*/
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public final synchronized void set(int i, long newValue) {
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array[i] = newValue;
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}
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/**
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* Eventually sets the element at position <tt>i</tt> to the given value.
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*
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* @param i the index
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* @param newValue the new value
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* @since 1.6
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*/
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public final void lazySet(int i, long newValue) {
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set(i, newValue);
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}
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/**
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* Atomically sets the element at position <tt>i</tt> to the given value
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* and returns the old value.
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*
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* @param i the index
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* @param newValue the new value
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* @return the previous value
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*/
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public final synchronized long getAndSet(int i, long newValue) {
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long v = array[i];
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array[i] = newValue;
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return v;
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}
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/**
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* Atomically sets the value to the given updated value
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* if the current value <tt>==</tt> the expected value.
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*
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* @param i the index
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* @param expect the expected value
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* @param update the new value
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* @return true if successful. False return indicates that
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* the actual value was not equal to the expected value.
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*/
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public final synchronized boolean compareAndSet(int i, long expect, long update) {
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if (array[i] == expect) {
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array[i] = update;
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return true;
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}
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return false;
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}
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/**
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* Atomically sets the value to the given updated value
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* if the current value <tt>==</tt> the expected value.
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* May fail spuriously and does not provide ordering guarantees,
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* so is only rarely an appropriate alternative to <tt>compareAndSet</tt>.
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*
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* @param i the index
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* @param expect the expected value
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* @param update the new value
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* @return true if successful.
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*/
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public final boolean weakCompareAndSet(int i, long expect, long update) {
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return compareAndSet(i, expect, update);
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}
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/**
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* Atomically increments by one the element at index <tt>i</tt>.
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*
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* @param i the index
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* @return the previous value
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*/
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public final synchronized long getAndIncrement(int i) {
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return array[i]++;
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}
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/**
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* Atomically decrements by one the element at index <tt>i</tt>.
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*
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* @param i the index
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* @return the previous value
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*/
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public final synchronized long getAndDecrement(int i) {
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return array[i]--;
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}
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/**
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* Atomically adds the given value to the element at index <tt>i</tt>.
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*
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* @param i the index
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* @param delta the value to add
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* @return the previous value
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*/
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public final synchronized long getAndAdd(int i, long delta) {
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long v = array[i];
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array[i] += delta;
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return v;
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}
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/**
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* Atomically increments by one the element at index <tt>i</tt>.
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*
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* @param i the index
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* @return the updated value
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*/
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public final synchronized long incrementAndGet(int i) {
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return ++array[i];
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}
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/**
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* Atomically decrements by one the element at index <tt>i</tt>.
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*
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* @param i the index
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* @return the updated value
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*/
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public final synchronized long decrementAndGet(int i) {
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return --array[i];
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}
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/**
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* Atomically adds the given value to the element at index <tt>i</tt>.
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*
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* @param i the index
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* @param delta the value to add
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* @return the updated value
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*/
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public synchronized long addAndGet(int i, long delta) {
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array[i] += delta;
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return array[i];
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}
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/**
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* Returns the String representation of the current values of array.
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* @return the String representation of the current values of array.
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*/
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public String toString() {
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if (array.length > 0) // force volatile read
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get(0);
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return Arrays.toString(array);
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}
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}
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