Package Summary  Overview Summary

class:ConstantCallSite [NONE]



  • 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:ConstantCallSite(java.lang.invoke.MethodHandle) [NONE]

  • 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

constructor:ConstantCallSite(java.lang.invoke.MethodType, java.lang.invoke.MethodHandle) [NONE]

  • ConstantCallSite

    protected ConstantCallSite(MethodType targetType,
                               MethodHandle createTargetHook)
                        throws Throwable
    
    Creates a call site with a permanent target, possibly bound to the call site itself.

    During construction of the call site, the createTargetHook is invoked to produce the actual target, as if by a call of the form (MethodHandle) createTargetHook.invoke(this) .

    Note that user code cannot perform such an action directly in a subclass constructor, since the target must be fixed before the ConstantCallSite constructor returns.

    The hook is said to bind the call site to a target method handle, and a typical action would be someTarget.bindTo(this). However, the hook is free to take any action whatever, including ignoring the call site and returning a constant target.

    The result returned by the hook must be a method handle of exactly the same type as the call site.

    While the hook is being called, the new ConstantCallSite object is in a partially constructed state. In this state, a call to getTarget, or any other attempt to use the target, will result in an IllegalStateException. It is legal at all times to obtain the call site's type using the type method.

    Parameters:
    targetType - the type of the method handle to be permanently associated with this call site
    createTargetHook - a method handle to invoke (on the call site) to produce the call site's target
    Throws:
    WrongMethodTypeException - if the hook cannot be invoked on the required arguments, or if the target returned by the hook is not of the given targetType
    NullPointerException - if the hook returns a null value
    ClassCastException - if the hook returns something other than a MethodHandle
    Throwable - anything else thrown by the hook function

method:getTarget() [NONE]

method:setTarget(java.lang.invoke.MethodHandle) [NONE]

method:dynamicInvoker() [NONE]

  • 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
    Throws:
    IllegalStateException - if the ConstantCallSite constructor has not completed