/*
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 *
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 *
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

package java.util.concurrent.atomic;

import java.lang.invoke.VarHandle;
import java.util.function.IntBinaryOperator;
import java.util.function.IntUnaryOperator;

/**
 * An {@code int} value that may be updated atomically. See the
 * {@link VarHandle} specification for descriptions of the properties
 * of atomic accesses. An {@code AtomicInteger} is used in
 * applications such as atomically incremented counters, and cannot be
 * used as a replacement for an {@link java.lang.Integer}. However,
 * this class does extend {@code Number} to allow uniform access by
 * tools and utilities that deal with numerically-based classes.
 *
 * @since 1.5
 * @author Doug Lea
 */
public class AtomicInteger extends Number implements java.io.Serializable {
 private static final long serialVersionUID = 6214790243416807050L;

 /*
 * This class intended to be implemented using VarHandles, but there
 * are unresolved cyclic startup dependencies.
 */
 private static final jdk.internal.misc.Unsafe U = jdk.internal.misc.Unsafe.getUnsafe();
 private static final long VALUE = U.objectFieldOffset(AtomicInteger.class, "value");

 private volatile int value;

 /**
 * Creates a new AtomicInteger with the given initial value.
 *
 * @param initialValue the initial value
 */
 public AtomicInteger(int initialValue) {
 value = initialValue;
 }

 /**
 * Creates a new AtomicInteger with initial value {@code 0}.
 */
 public AtomicInteger() {
 }

 /**
 * Returns the current value,
 * with memory effects as specified by {@link VarHandle#getVolatile}.
 *
 * @return the current value
 */
 public final int get() {
 return value;
 }

 /**
 * Sets the value to {@code newValue},
 * with memory effects as specified by {@link VarHandle#setVolatile}.
 *
 * @param newValue the new value
 */
 public final void set(int newValue) {
 value = newValue;
 }

 /**
 * Sets the value to {@code newValue},
 * with memory effects as specified by {@link VarHandle#setRelease}.
 *
 * @param newValue the new value
 * @since 1.6
 */
 public final void lazySet(int newValue) {
 U.putIntRelease(this, VALUE, newValue);
 }

 /**
 * Atomically sets the value to {@code newValue} and returns the old value,
 * with memory effects as specified by {@link VarHandle#getAndSet}.
 *
 * @param newValue the new value
 * @return the previous value
 */
 public final int getAndSet(int newValue) {
 return U.getAndSetInt(this, VALUE, newValue);
 }

 /**
 * Atomically sets the value to {@code newValue}
 * if the current value {@code == expectedValue},
 * with memory effects as specified by {@link VarHandle#compareAndSet}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful. False return indicates that
 * the actual value was not equal to the expected value.
 */
 public final boolean compareAndSet(int expectedValue, int newValue) {
 return U.compareAndSetInt(this, VALUE, expectedValue, newValue);
 }

 /**
 * Possibly atomically sets the value to {@code newValue}
 * if the current value {@code == expectedValue},
 * with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
 *
 * @deprecated This method has plain memory effects but the method
 * name implies volatile memory effects (see methods such as
 * {@link #compareAndExchange} and {@link #compareAndSet}). To avoid
 * confusion over plain or volatile memory effects it is recommended that
 * the method {@link #weakCompareAndSetPlain} be used instead.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful
 * @see #weakCompareAndSetPlain
 */
 @Deprecated(since="9")
 public final boolean weakCompareAndSet(int expectedValue, int newValue) {
 return U.weakCompareAndSetIntPlain(this, VALUE, expectedValue, newValue);
 }

 /**
 * Possibly atomically sets the value to {@code newValue}
 * if the current value {@code == expectedValue},
 * with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful
 * @since 9
 */
 public final boolean weakCompareAndSetPlain(int expectedValue, int newValue) {
 return U.weakCompareAndSetIntPlain(this, VALUE, expectedValue, newValue);
 }

 /**
 * Atomically increments the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * <p>Equivalent to {@code getAndAdd(1)}.
 *
 * @return the previous value
 */
 public final int getAndIncrement() {
 return U.getAndAddInt(this, VALUE, 1);
 }

 /**
 * Atomically decrements the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * <p>Equivalent to {@code getAndAdd(-1)}.
 *
 * @return the previous value
 */
 public final int getAndDecrement() {
 return U.getAndAddInt(this, VALUE, -1);
 }

 /**
 * Atomically adds the given value to the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * @param delta the value to add
 * @return the previous value
 */
 public final int getAndAdd(int delta) {
 return U.getAndAddInt(this, VALUE, delta);
 }

 /**
 * Atomically increments the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * <p>Equivalent to {@code addAndGet(1)}.
 *
 * @return the updated value
 */
 public final int incrementAndGet() {
 return U.getAndAddInt(this, VALUE, 1) + 1;
 }

 /**
 * Atomically decrements the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * <p>Equivalent to {@code addAndGet(-1)}.
 *
 * @return the updated value
 */
 public final int decrementAndGet() {
 return U.getAndAddInt(this, VALUE, -1) - 1;
 }

 /**
 * Atomically adds the given value to the current value,
 * with memory effects as specified by {@link VarHandle#getAndAdd}.
 *
 * @param delta the value to add
 * @return the updated value
 */
 public final int addAndGet(int delta) {
 return U.getAndAddInt(this, VALUE, delta) + delta;
 }

 /**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the current value with the results of
 * applying the given function, returning the previous value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the previous value
 * @since 1.8
 */
 public final int getAndUpdate(IntUnaryOperator updateFunction) {
 int prev = get(), next = 0;
 for (boolean haveNext = false;;) {
 if (!haveNext)
 next = updateFunction.applyAsInt(prev);
 if (weakCompareAndSetVolatile(prev, next))
 return prev;
 haveNext = (prev == (prev = get()));
 }
 }

 /**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the current value with the results of
 * applying the given function, returning the updated value. The
 * function should be side-effect-free, since it may be re-applied
 * when attempted updates fail due to contention among threads.
 *
 * @param updateFunction a side-effect-free function
 * @return the updated value
 * @since 1.8
 */
 public final int updateAndGet(IntUnaryOperator updateFunction) {
 int prev = get(), next = 0;
 for (boolean haveNext = false;;) {
 if (!haveNext)
 next = updateFunction.applyAsInt(prev);
 if (weakCompareAndSetVolatile(prev, next))
 return next;
 haveNext = (prev == (prev = get()));
 }
 }

 /**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the current value with the results of
 * applying the given function to the current and given values,
 * returning the previous value. The function should be
 * side-effect-free, since it may be re-applied when attempted
 * updates fail due to contention among threads. The function is
 * applied with the current value as its first argument, and the
 * given update as the second argument.
 *
 * @param x the update value
 * @param accumulatorFunction a side-effect-free function of two arguments
 * @return the previous value
 * @since 1.8
 */
 public final int getAndAccumulate(int x,
 IntBinaryOperator accumulatorFunction) {
 int prev = get(), next = 0;
 for (boolean haveNext = false;;) {
 if (!haveNext)
 next = accumulatorFunction.applyAsInt(prev, x);
 if (weakCompareAndSetVolatile(prev, next))
 return prev;
 haveNext = (prev == (prev = get()));
 }
 }

 /**
 * Atomically updates (with memory effects as specified by {@link
 * VarHandle#compareAndSet}) the current value with the results of
 * applying the given function to the current and given values,
 * returning the updated value. The function should be
 * side-effect-free, since it may be re-applied when attempted
 * updates fail due to contention among threads. The function is
 * applied with the current value as its first argument, and the
 * given update as the second argument.
 *
 * @param x the update value
 * @param accumulatorFunction a side-effect-free function of two arguments
 * @return the updated value
 * @since 1.8
 */
 public final int accumulateAndGet(int x,
 IntBinaryOperator accumulatorFunction) {
 int prev = get(), next = 0;
 for (boolean haveNext = false;;) {
 if (!haveNext)
 next = accumulatorFunction.applyAsInt(prev, x);
 if (weakCompareAndSetVolatile(prev, next))
 return next;
 haveNext = (prev == (prev = get()));
 }
 }

 /**
 * Returns the String representation of the current value.
 * @return the String representation of the current value
 */
 public String toString() {
 return Integer.toString(get());
 }

 /**
 * Returns the current value of this {@code AtomicInteger} as an
 * {@code int},
 * with memory effects as specified by {@link VarHandle#getVolatile}.
 *
 * Equivalent to {@link #get()}.
 */
 public int intValue() {
 return get();
 }

 /**
 * Returns the current value of this {@code AtomicInteger} as a
 * {@code long} after a widening primitive conversion,
 * with memory effects as specified by {@link VarHandle#getVolatile}.
 * @jls 5.1.2 Widening Primitive Conversions
 */
 public long longValue() {
 return (long)get();
 }

 /**
 * Returns the current value of this {@code AtomicInteger} as a
 * {@code float} after a widening primitive conversion,
 * with memory effects as specified by {@link VarHandle#getVolatile}.
 * @jls 5.1.2 Widening Primitive Conversions
 */
 public float floatValue() {
 return (float)get();
 }

 /**
 * Returns the current value of this {@code AtomicInteger} as a
 * {@code double} after a widening primitive conversion,
 * with memory effects as specified by {@link VarHandle#getVolatile}.
 * @jls 5.1.2 Widening Primitive Conversions
 */
 public double doubleValue() {
 return (double)get();
 }

 // jdk9

 /**
 * Returns the current value, with memory semantics of reading as
 * if the variable was declared non-{@code volatile}.
 *
 * @return the value
 * @since 9
 */
 public final int getPlain() {
 return U.getInt(this, VALUE);
 }

 /**
 * Sets the value to {@code newValue}, with memory semantics
 * of setting as if the variable was declared non-{@code volatile}
 * and non-{@code final}.
 *
 * @param newValue the new value
 * @since 9
 */
 public final void setPlain(int newValue) {
 U.putInt(this, VALUE, newValue);
 }

 /**
 * Returns the current value,
 * with memory effects as specified by {@link VarHandle#getOpaque}.
 *
 * @return the value
 * @since 9
 */
 public final int getOpaque() {
 return U.getIntOpaque(this, VALUE);
 }

 /**
 * Sets the value to {@code newValue},
 * with memory effects as specified by {@link VarHandle#setOpaque}.
 *
 * @param newValue the new value
 * @since 9
 */
 public final void setOpaque(int newValue) {
 U.putIntOpaque(this, VALUE, newValue);
 }

 /**
 * Returns the current value,
 * with memory effects as specified by {@link VarHandle#getAcquire}.
 *
 * @return the value
 * @since 9
 */
 public final int getAcquire() {
 return U.getIntAcquire(this, VALUE);
 }

 /**
 * Sets the value to {@code newValue},
 * with memory effects as specified by {@link VarHandle#setRelease}.
 *
 * @param newValue the new value
 * @since 9
 */
 public final void setRelease(int newValue) {
 U.putIntRelease(this, VALUE, newValue);
 }

 /**
 * Atomically sets the value to {@code newValue} if the current value,
 * referred to as the <em>witness value</em>, {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#compareAndExchange}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return the witness value, which will be the same as the
 * expected value if successful
 * @since 9
 */
 public final int compareAndExchange(int expectedValue, int newValue) {
 return U.compareAndExchangeInt(this, VALUE, expectedValue, newValue);
 }

 /**
 * Atomically sets the value to {@code newValue} if the current value,
 * referred to as the <em>witness value</em>, {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#compareAndExchangeAcquire}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return the witness value, which will be the same as the
 * expected value if successful
 * @since 9
 */
 public final int compareAndExchangeAcquire(int expectedValue, int newValue) {
 return U.compareAndExchangeIntAcquire(this, VALUE, expectedValue, newValue);
 }

 /**
 * Atomically sets the value to {@code newValue} if the current value,
 * referred to as the <em>witness value</em>, {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#compareAndExchangeRelease}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return the witness value, which will be the same as the
 * expected value if successful
 * @since 9
 */
 public final int compareAndExchangeRelease(int expectedValue, int newValue) {
 return U.compareAndExchangeIntRelease(this, VALUE, expectedValue, newValue);
 }

 /**
 * Possibly atomically sets the value to {@code newValue} if
 * the current value {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#weakCompareAndSet}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful
 * @since 9
 */
 public final boolean weakCompareAndSetVolatile(int expectedValue, int newValue) {
 return U.weakCompareAndSetInt(this, VALUE, expectedValue, newValue);
 }

 /**
 * Possibly atomically sets the value to {@code newValue} if
 * the current value {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#weakCompareAndSetAcquire}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful
 * @since 9
 */
 public final boolean weakCompareAndSetAcquire(int expectedValue, int newValue) {
 return U.weakCompareAndSetIntAcquire(this, VALUE, expectedValue, newValue);
 }

 /**
 * Possibly atomically sets the value to {@code newValue} if
 * the current value {@code == expectedValue},
 * with memory effects as specified by
 * {@link VarHandle#weakCompareAndSetRelease}.
 *
 * @param expectedValue the expected value
 * @param newValue the new value
 * @return {@code true} if successful
 * @since 9
 */
 public final boolean weakCompareAndSetRelease(int expectedValue, int newValue) {
 return U.weakCompareAndSetIntRelease(this, VALUE, expectedValue, newValue);
 }

}