java.lang.invoke

Class ConstantCallSite

java.lang.Object

java.lang.invoke.CallSite

java.lang.invoke.ConstantCallSite

public class ConstantCallSite
extends CallSite

A ConstantCallSite is a CallSite whose target is permanent, and can never be changed. An invokedynamic instruction linked to a ConstantCallSite is permanently bound to the call site's target.

Constructor Summary

Constructors

Constructor and Description
ConstantCallSite(MethodHandle target) Creates a call site with a permanent target.

Method Summary

Methods

Modifier and Type	Method and Description
MethodHandle	dynamicInvoker() Returns this call site's permanent target.
MethodHandle	getTarget() Returns the target method of the call site, which behaves like a final field of the ConstantCallSite.
void	setTarget(MethodHandle ignore) Always throws an UnsupportedOperationException.

Methods inherited from class java.lang.invoke.CallSite

type

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConstantCallSite

public ConstantCallSite(MethodHandle target)

Creates a call site with a permanent target.

Parameters:

target - the target to be permanently associated with this call site

Throws:

NullPointerException - if the proposed target is null

Method Detail

getTarget

public final MethodHandle getTarget()

Returns the target method of the call site, which behaves like a final field of the ConstantCallSite. That is, the the target is always the original value passed to the constructor call which created this instance.

Specified by:

getTarget in class CallSite

Returns:

the immutable linkage state of this call site, a constant method handle

Throws:

UnsupportedOperationException - because this kind of call site cannot change its target

See Also:

ConstantCallSite, VolatileCallSite, CallSite.setTarget(java.lang.invoke.MethodHandle), getTarget(), MutableCallSite.getTarget(), VolatileCallSite.getTarget()

setTarget

public final void setTarget(MethodHandle ignore)

Always throws an UnsupportedOperationException. This kind of call site cannot change its target.

Specified by:

setTarget in class CallSite

Parameters:

ignore - a new target proposed for the call site, which is ignored

Throws:

UnsupportedOperationException - because this kind of call site cannot change its target

See Also:

CallSite.getTarget(), setTarget(java.lang.invoke.MethodHandle), MutableCallSite.setTarget(java.lang.invoke.MethodHandle), VolatileCallSite.setTarget(java.lang.invoke.MethodHandle)

dynamicInvoker

public final MethodHandle dynamicInvoker()

Returns this call site's permanent target. Since that target will never change, this is a correct implementation of CallSite.dynamicInvoker.

Specified by:

dynamicInvoker in class CallSite

Returns:

the immutable linkage state of this call site, a constant method handle