# Print output for @column tags ?> VolatileCallSite - Android SDK | Android Developers

Most visited

Recently visited

VolatileCallSite

public class VolatileCallSite
extends CallSite

java.lang.Object
   ↳ java.lang.invoke.CallSite
     ↳ java.lang.invoke.VolatileCallSite


A VolatileCallSite is a CallSite whose target acts like a volatile variable. An invokedynamic instruction linked to a VolatileCallSite sees updates to its call site target immediately, even if the update occurs in another thread. There may be a performance penalty for such tight coupling between threads.

In other respects, a VolatileCallSite is interchangeable with MutableCallSite.

See also:

Summary

Public constructors

VolatileCallSite(MethodType type)

Creates a call site with a volatile binding to its target.

VolatileCallSite(MethodHandle target)

Creates a call site with a volatile binding to its target.

Public methods

final MethodHandle dynamicInvoker()

Produces a method handle equivalent to an invokedynamic instruction which has been linked to this call site.

final MethodHandle getTarget()

Returns the target method of the call site, which behaves like a volatile field of the VolatileCallSite.

void setTarget(MethodHandle newTarget)

Updates the target method of this call site, as a volatile variable.

Inherited methods

Public constructors

VolatileCallSite

public VolatileCallSite (MethodType type)

Creates a call site with a volatile binding to its target. The initial target is set to a method handle of the given type which will throw an IllegalStateException if called.

Parameters
type MethodType: the method type that this call site will have

Throws
NullPointerException if the proposed type is null

VolatileCallSite

public VolatileCallSite (MethodHandle target)

Creates a call site with a volatile binding to its target. The target is set to the given value.

Parameters
target MethodHandle: the method handle that will be the initial target of the call site

Throws
NullPointerException if the proposed target is null

Public methods

dynamicInvoker

public final MethodHandle dynamicInvoker ()

Produces a method handle equivalent to an invokedynamic instruction which has been linked to this call site.

This method is equivalent to the following code:

MethodHandle getTarget, invoker, result;
 getTarget = MethodHandles.publicLookup().bind(this, "getTarget", MethodType.methodType(MethodHandle.class));
 invoker = MethodHandles.exactInvoker(this.type());
 result = MethodHandles.foldArguments(invoker, getTarget)
 

Returns
MethodHandle a method handle which always invokes this call site's current target

getTarget

public final MethodHandle getTarget ()

Returns the target method of the call site, which behaves like a volatile field of the VolatileCallSite.

The interactions of getTarget with memory are the same as of a read from a volatile field.

In particular, the current thread is required to issue a fresh read of the target from memory, and must not fail to see a recent update to the target by another thread.

Returns
MethodHandle the linkage state of this call site, a method handle which can change over time

See also:

setTarget

public void setTarget (MethodHandle newTarget)

Updates the target method of this call site, as a volatile variable. The type of the new target must agree with the type of the old target.

The interactions with memory are the same as of a write to a volatile field. In particular, any threads is guaranteed to see the updated target the next time it calls getTarget.

Parameters
newTarget MethodHandle: the new target

Throws
NullPointerException if the proposed new target is null
WrongMethodTypeException if the proposed new target has a method type that differs from the previous target

See also: