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Diffstat (limited to 'kamon-core/src/main/java/kamon/jsr166/LongMaxUpdater.java')
-rw-r--r-- | kamon-core/src/main/java/kamon/jsr166/LongMaxUpdater.java | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/kamon-core/src/main/java/kamon/jsr166/LongMaxUpdater.java b/kamon-core/src/main/java/kamon/jsr166/LongMaxUpdater.java deleted file mode 100644 index fc9ea4e5..00000000 --- a/kamon-core/src/main/java/kamon/jsr166/LongMaxUpdater.java +++ /dev/null @@ -1,191 +0,0 @@ -/* - * 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 kamon.jsr166; -import java.io.Serializable; - -/** - * One or more variables that together maintain a running {@code long} - * maximum with initial value {@code Long.MIN_VALUE}. When updates - * (method {@link #update}) are contended across threads, the set of - * variables may grow dynamically to reduce contention. Method {@link - * #max} (or, equivalently, {@link #longValue}) returns the current - * maximum across the variables maintaining updates. - * - * <p>This class extends {@link Number}, but does <em>not</em> define - * methods such as {@code equals}, {@code hashCode} and {@code - * compareTo} because instances are expected to be mutated, and so are - * not useful as collection keys. - * - * <p><em>jsr166e note: This class is targeted to be placed in - * java.util.concurrent.atomic.</em> - * - * @since 1.8 - * @author Doug Lea - */ -public class LongMaxUpdater extends Striped64 implements Serializable { - private static final long serialVersionUID = 7249069246863182397L; - - /** - * Version of max for use in retryUpdate - */ - final long fn(long v, long x) { return v > x ? v : x; } - - /** - * Creates a new instance with initial maximum of {@code - * Long.MIN_VALUE}. - */ - public LongMaxUpdater() { - base = Long.MIN_VALUE; - } - - /** - * Creates a new instance with the given initialValue - */ - public LongMaxUpdater(long initialValue) { - base = initialValue; - } - - - /** - * Updates the maximum to be at least the given value. - * - * @param x the value to update - */ - public void update(long x) { - Cell[] as; long b, v; HashCode hc; Cell a; int n; - if ((as = cells) != null || - (b = base) < x && !casBase(b, x)) { - boolean uncontended = true; - int h = (hc = threadHashCode.get()).code; - if (as == null || (n = as.length) < 1 || - (a = as[(n - 1) & h]) == null || - ((v = a.value) < x && !(uncontended = a.cas(v, x)))) - retryUpdate(x, hc, uncontended); - } - } - - /** - * Returns the current maximum. The returned value is - * <em>NOT</em> an atomic snapshot; invocation in the absence of - * concurrent updates returns an accurate result, but concurrent - * updates that occur while the value is being calculated might - * not be incorporated. - * - * @return the maximum - */ - public long max() { - Cell[] as = cells; - long max = base; - if (as != null) { - int n = as.length; - long v; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null && (v = a.value) > max) - max = v; - } - } - return max; - } - - /** - * Resets variables maintaining updates to {@code Long.MIN_VALUE}. - * This method may be a useful alternative to creating a new - * updater, but is only effective if there are no concurrent - * updates. Because this method is intrinsically racy, it should - * only be used when it is known that no threads are concurrently - * updating. - */ - public void reset() { - internalReset(Long.MIN_VALUE); - } - - /** - * Equivalent in effect to {@link #max} followed by {@link - * #reset}. This method may apply for example during quiescent - * points between multithreaded computations. If there are - * updates concurrent with this method, the returned value is - * <em>not</em> guaranteed to be the final value occurring before - * the reset. - * - * @return the maximum - */ - public long maxThenReset(long newValue) { - Cell[] as = cells; - long max = base; - base = newValue; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) { - long v = a.value; - a.value = newValue; - if (v > max) - max = v; - } - } - } - return max; - } - - /** - * Returns the String representation of the {@link #max}. - * @return the String representation of the {@link #max} - */ - public String toString() { - return Long.toString(max()); - } - - /** - * Equivalent to {@link #max}. - * - * @return the maximum - */ - public long longValue() { - return max(); - } - - /** - * Returns the {@link #max} as an {@code int} after a narrowing - * primitive conversion. - */ - public int intValue() { - return (int)max(); - } - - /** - * Returns the {@link #max} as a {@code float} - * after a widening primitive conversion. - */ - public float floatValue() { - return (float)max(); - } - - /** - * Returns the {@link #max} as a {@code double} after a widening - * primitive conversion. - */ - public double doubleValue() { - return (double)max(); - } - - private void writeObject(java.io.ObjectOutputStream s) - throws java.io.IOException { - s.defaultWriteObject(); - s.writeLong(max()); - } - - private void readObject(java.io.ObjectInputStream s) - throws java.io.IOException, ClassNotFoundException { - s.defaultReadObject(); - busy = 0; - cells = null; - base = s.readLong(); - } - -} |