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0N/A */
0N/A
0N/Apackage java.lang.invoke;
0N/A
0N/A/**
0N/A * A {@code VolatileCallSite} is a {@link CallSite} whose target acts like a volatile variable.
0N/A * An {@code invokedynamic} instruction linked to a {@code VolatileCallSite} sees updates
0N/A * to its call site target immediately, even if the update occurs in another thread.
0N/A * There may be a performance penalty for such tight coupling between threads.
0N/A * <p>
0N/A * Unlike {@code MutableCallSite}, there is no
0N/A * {@linkplain MutableCallSite#syncAll syncAll operation} on volatile
0N/A * call sites, since every write to a volatile variable is implicitly
0N/A * synchronized with reader threads.
0N/A * <p>
0N/A * In other respects, a {@code VolatileCallSite} is interchangeable
0N/A * with {@code MutableCallSite}.
0N/A * @see MutableCallSite
0N/A * @author John Rose, JSR 292 EG
0N/A */
0N/Apublic class VolatileCallSite extends CallSite {
0N/A /**
0N/A * Creates a call site with a volatile binding to its target.
0N/A * The initial target is set to a method handle
0N/A * of the given type which will throw an {@code IllegalStateException} if called.
0N/A * @param type the method type that this call site will have
0N/A * @throws NullPointerException if the proposed type is null
0N/A */
0N/A public VolatileCallSite(MethodType type) {
0N/A super(type);
0N/A }
0N/A
0N/A /**
0N/A * Creates a call site with a volatile binding to its target.
0N/A * The target is set to the given value.
0N/A * @param target the method handle that will be the initial target of the call site
0N/A * @throws NullPointerException if the proposed target is null
0N/A */
0N/A public VolatileCallSite(MethodHandle target) {
0N/A super(target);
0N/A }
0N/A
0N/A /**
0N/A * Returns the target method of the call site, which behaves
0N/A * like a {@code volatile} field of the {@code VolatileCallSite}.
0N/A * <p>
0N/A * The interactions of {@code getTarget} with memory are the same
0N/A * as of a read from a {@code volatile} field.
0N/A * <p>
0N/A * In particular, the current thread is required to issue a fresh
0N/A * read of the target from memory, and must not fail to see
0N/A * a recent update to the target by another thread.
0N/A *
0N/A * @return the linkage state of this call site, a method handle which can change over time
0N/A * @see #setTarget
0N/A */
0N/A @Override public final MethodHandle getTarget() {
0N/A return getTargetVolatile();
0N/A }
0N/A
0N/A /**
0N/A * Updates the target method of this call site, as a volatile variable.
0N/A * The type of the new target must agree with the type of the old target.
0N/A * <p>
0N/A * The interactions with memory are the same as of a write to a volatile field.
0N/A * In particular, any threads is guaranteed to see the updated target
0N/A * the next time it calls {@code getTarget}.
0N/A * @param newTarget the new target
0N/A * @throws NullPointerException if the proposed new target is null
0N/A * @throws WrongMethodTypeException if the proposed new target
0N/A * has a method type that differs from the previous target
0N/A * @see #getTarget
0N/A */
0N/A @Override public void setTarget(MethodHandle newTarget) {
0N/A checkTargetChange(getTargetVolatile(), newTarget);
0N/A setTargetVolatile(newTarget);
0N/A }
0N/A
0N/A /**
0N/A * {@inheritDoc}
0N/A */
0N/A @Override
0N/A public final MethodHandle dynamicInvoker() {
0N/A return makeDynamicInvoker();
0N/A }
0N/A}
0N/A