Scala example source code file (AtomicInteger.java)

This example Scala source code file (AtomicInteger.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

actor, atomicinteger, number, string, thread, threadpool

The AtomicInteger.java Scala example source code

/*
 * 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/licenses/publicdomain
 */

package scala.actors.threadpool;

/**
 * An {@code int} value that may be updated atomically.  See the
 * {@link edu.emory.mathcs.backport.java.util.concurrent.atomic} package specification for
 * description of the properties of atomic variables. 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;

    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() {
    }

    /**
     * Gets the current value.
     *
     * @return the current value
     */
    public final int get() {
        return value;
    }

    /**
     * Sets to the given value.
     *
     * @param newValue the new value
     */
    public final synchronized void set(int newValue) {
        value = newValue;
    }

    /**
     * Eventually sets to the given value.
     *
     * @param newValue the new value
     * @since 1.6
     */
    public final synchronized void lazySet(int newValue) {
        value = newValue;
    }

    /**
     * Atomically sets to the given value and returns the old value.
     *
     * @param newValue the new value
     * @return the previous value
     */
    public final synchronized int getAndSet(int newValue) {
        int old = value;
        value = newValue;
        return old;
    }

    /**
     * Atomically sets the value to the given updated value
     * if the current value {@code ==} the expected value.
     *
     * @param expect the expected value
     * @param update the new value
     * @return true if successful. False return indicates that
     * the actual value was not equal to the expected value.
     */
    public final synchronized boolean compareAndSet(int expect, int update) {
        if (value == expect) {
            value = update;
            return true;
        }
        else {
            return false;
        }
    }

    /**
     * Atomically sets the value to the given updated value
     * if the current value {@code ==} the expected value.
     *
     * <p>May <a href="package-summary.html#Spurious">fail spuriously</a>
     * and does not provide ordering guarantees, so is only rarely an
     * appropriate alternative to {@code compareAndSet}.
     *
     * @param expect the expected value
     * @param update the new value
     * @return true if successful.
     */
    public final synchronized boolean weakCompareAndSet(int expect, int update) {
        if (value == expect) {
            value = update;
            return true;
        }
        else {
            return false;
        }
    }


    /**
     * Atomically increments by one the current value.
     *
     * @return the previous value
     */
    public final synchronized int getAndIncrement() {
        return value++;
    }


    /**
     * Atomically decrements by one the current value.
     *
     * @return the previous value
     */
    public final synchronized int getAndDecrement() {
        return value--;
    }


    /**
     * Atomically adds the given value to the current value.
     *
     * @param delta the value to add
     * @return the previous value
     */
    public final synchronized int getAndAdd(int delta) {
        int old = value;
        value += delta;
        return old;
    }

    /**
     * Atomically increments by one the current value.
     *
     * @return the updated value
     */
    public final synchronized int incrementAndGet() {
        return ++value;
    }

    /**
     * Atomically decrements by one the current value.
     *
     * @return the updated value
     */
    public final synchronized int decrementAndGet() {
        return --value;
    }


    /**
     * Atomically adds the given value to the current value.
     *
     * @param delta the value to add
     * @return the updated value
     */
    public final synchronized int addAndGet(int delta) {
        return value += delta;
    }

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


    public int intValue() {
        return get();
    }

    public long longValue() {
        return (long)get();
    }

    public float floatValue() {
        return (float)get();
    }

    public double doubleValue() {
        return (double)get();
    }

}