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*/ |
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package jsr166e; |
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import java.io.IOException; |
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import java.io.Serializable; |
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import java.io.ObjectInputStream; |
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import java.io.ObjectOutputStream; |
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/** |
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* One or more variables that together maintain a running {@code double} |
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* current maximum across the variables maintaining updates. |
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* |
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* <p>This class extends {@link Number}, but does <em>not</em> define |
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* methods such as {@code hashCode} and {@code compareTo} because |
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* instances are expected to be mutated, and so are not useful as |
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* collection keys. |
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* methods such as {@code equals}, {@code hashCode} and {@code |
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* compareTo} because instances are expected to be mutated, and so are |
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* not useful as collection keys. |
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* |
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* <p><em>jsr166e note: This class is targeted to be placed in |
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* java.util.concurrent.atomic.</em> |
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*/ |
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public void update(double x) { |
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long lx = Double.doubleToRawLongBits(x); |
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Cell[] as; long b, v; HashCode hc; Cell a; int n; |
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Cell[] as; long b, v; int[] hc; Cell a; int n; |
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if ((as = cells) != null || |
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(Double.longBitsToDouble(b = base) < x && !casBase(b, lx))) { |
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boolean uncontended = true; |
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int h = (hc = threadHashCode.get()).code; |
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if (as == null || (n = as.length) < 1 || |
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(a = as[(n - 1) & h]) == null || |
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if ((hc = threadHashCode.get()) == null || |
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as == null || (n = as.length) < 1 || |
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(a = as[(n - 1) & hc[0]]) == null || |
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(Double.longBitsToDouble(v = a.value) < x && |
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!(uncontended = a.cas(v, lx)))) |
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retryUpdate(lx, hc, uncontended); |
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/** |
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* Returns the current maximum. The returned value is |
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* <em>NOT</em> an atomic snapshot: Invocation in the absence of |
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* <em>NOT</em> an atomic snapshot; invocation in the absence of |
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* concurrent updates returns an accurate result, but concurrent |
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* updates that occur while the value is being calculated might |
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* not be incorporated. |
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s.writeDouble(max()); |
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} |
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private void readObject(ObjectInputStream s) |
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throws IOException, ClassNotFoundException { |
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private void readObject(java.io.ObjectInputStream s) |
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throws java.io.IOException, ClassNotFoundException { |
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s.defaultReadObject(); |
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busy = 0; |
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cells = null; |