MutableCallSite Class

Reference

Definition

Namespace:: Java.Lang.Invoke

Assembly:: Mono.Android.dll

Important

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A MutableCallSite is a CallSite whose target variable behaves like an ordinary field.

[Android.Runtime.Register("java/lang/invoke/MutableCallSite", ApiSince=26, DoNotGenerateAcw=true)]
public class MutableCallSite : Java.Lang.Invoke.CallSite

[<Android.Runtime.Register("java/lang/invoke/MutableCallSite", ApiSince=26, DoNotGenerateAcw=true)>]
type MutableCallSite = class
    inherit CallSite

Inheritance: Object

Object

CallSite
MutableCallSite

Attributes: RegisterAttribute

Remarks

A MutableCallSite is a CallSite whose target variable behaves like an ordinary field. An invokedynamic instruction linked to a MutableCallSite delegates all calls to the site's current target. The CallSite#dynamicInvoker dynamic invoker of a mutable call site also delegates each call to the site's current target.

Here is an example of a mutable call site which introduces a state variable into a method handle chain.  <blockquote>

{@code
            MutableCallSite name = new MutableCallSite(MethodType.methodType(String.class));
            MethodHandle MH_name = name.dynamicInvoker();
            MethodType MT_str1 = MethodType.methodType(String.class);
            MethodHandle MH_upcase = MethodHandles.lookup()
                .findVirtual(String.class, "toUpperCase", MT_str1);
            MethodHandle worker1 = MethodHandles.filterReturnValue(MH_name, MH_upcase);
            name.setTarget(MethodHandles.constant(String.class, "Rocky"));
            assertEquals("ROCKY", (String) worker1.invokeExact());
            name.setTarget(MethodHandles.constant(String.class, "Fred"));
            assertEquals("FRED", (String) worker1.invokeExact());
            // (mutation can be continued indefinitely)
            }

</blockquote>

The same call site may be used in several places at once. <blockquote>

{@code
            MethodType MT_str2 = MethodType.methodType(String.class, String.class);
            MethodHandle MH_cat = lookup().findVirtual(String.class,
              "concat", methodType(String.class, String.class));
            MethodHandle MH_dear = MethodHandles.insertArguments(MH_cat, 1, ", dear?");
            MethodHandle worker2 = MethodHandles.filterReturnValue(MH_name, MH_dear);
            assertEquals("Fred, dear?", (String) worker2.invokeExact());
            name.setTarget(MethodHandles.constant(String.class, "Wilma"));
            assertEquals("WILMA", (String) worker1.invokeExact());
            assertEquals("Wilma, dear?", (String) worker2.invokeExact());
            }

</blockquote>

<em>Non-synchronization of target values:</em> A write to a mutable call site's target does not force other threads to become aware of the updated value. Threads which do not perform suitable synchronization actions relative to the updated call site may cache the old target value and delay their use of the new target value indefinitely. (This is a normal consequence of the Java Memory Model as applied to object fields.)

For target values which will be frequently updated, consider using a VolatileCallSite volatile call site instead.

Java documentation for java.lang.invoke.MutableCallSite.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

MutableCallSite(IntPtr, JniHandleOwnership)
MutableCallSite(MethodHandle)	Creates a call site object with an initial target method handle.
MutableCallSite(MethodType)	Creates a blank call site object with the given method type.

Properties

Class	Returns the runtime class of this `Object`. (Inherited from Object)
Handle	The handle to the underlying Android instance. (Inherited from Object)
JniIdentityHashCode	(Inherited from Object)
JniPeerMembers
PeerReference	(Inherited from Object)
Target	Returns the target method of the call site, which behaves like a normal field of the `MutableCallSite`. -or- Updates the target method of this call site, as a normal variable.
ThresholdClass
ThresholdType

Methods

Clone()	Creates and returns a copy of this object. (Inherited from Object)
Dispose()	(Inherited from Object)
Dispose(Boolean)	(Inherited from Object)
DynamicInvoker()	To be added
Equals(Object)	Indicates whether some other object is "equal to" this one. (Inherited from Object)
GetHashCode()	Returns a hash code value for the object. (Inherited from Object)
JavaFinalize()	Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. (Inherited from Object)
Notify()	Wakes up a single thread that is waiting on this object's monitor. (Inherited from Object)
NotifyAll()	Wakes up all threads that are waiting on this object's monitor. (Inherited from Object)
SetHandle(IntPtr, JniHandleOwnership)	Sets the Handle property. (Inherited from Object)
ToArray<T>()	(Inherited from Object)
ToString()	Returns a string representation of the object. (Inherited from Object)
Type()	Returns the type of this call site's target. (Inherited from CallSite)
UnregisterFromRuntime()	(Inherited from Object)
Wait()	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>. (Inherited from Object)
Wait(Int64)	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object)
Wait(Int64, Int32)	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object)

Explicit Interface Implementations

IJavaPeerable.Disposed()	(Inherited from Object)
IJavaPeerable.DisposeUnlessReferenced()	(Inherited from Object)
IJavaPeerable.Finalized()	(Inherited from Object)
IJavaPeerable.JniManagedPeerState	(Inherited from Object)
IJavaPeerable.SetJniIdentityHashCode(Int32)	(Inherited from Object)
IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates)	(Inherited from Object)
IJavaPeerable.SetPeerReference(JniObjectReference)	(Inherited from Object)

Extension Methods

JavaCast<TResult>(IJavaObject)	Performs an Android runtime-checked type conversion.
JavaCast<TResult>(IJavaObject)
GetJniTypeName(IJavaPeerable)

Applies to