Exchanger Class

Definition

[Android.Runtime.Register("java/util/concurrent/Exchanger", DoNotGenerateAcw=true)]
[Java.Interop.JavaTypeParameters(new System.String[] { "V" })]
public class Exchanger : Java.Lang.Object

[<Android.Runtime.Register("java/util/concurrent/Exchanger", DoNotGenerateAcw=true)>]
[<Java.Interop.JavaTypeParameters(new System.String[] { "V" })>]
type Exchanger = class
    inherit Object

Inheritance

Object

Object

Exchanger

Attributes

RegisterAttribute JavaTypeParametersAttribute

Remarks

A synchronization point at which threads can pair and swap elements within pairs. Each thread presents some object on entry to the #exchange exchange method, matches with a partner thread, and receives its partner's object on return. An Exchanger may be viewed as a bidirectional form of a SynchronousQueue. Exchangers may be useful in applications such as genetic algorithms and pipeline designs.

<b>Sample Usage:</b> Here are the highlights of a class that uses an Exchanger to swap buffers between threads so that the thread filling the buffer gets a freshly emptied one when it needs it, handing off the filled one to the thread emptying the buffer.

{@code
            class FillAndEmpty {
              Exchanger<DataBuffer> exchanger = new Exchanger<>();
              DataBuffer initialEmptyBuffer = ...; // a made-up type
              DataBuffer initialFullBuffer = ...;

              class FillingLoop implements Runnable {
                public void run() {
                  DataBuffer currentBuffer = initialEmptyBuffer;
                  try {
                    while (currentBuffer != null) {
                      addToBuffer(currentBuffer);
                      if (currentBuffer.isFull())
                        currentBuffer = exchanger.exchange(currentBuffer);
                    }
                  } catch (InterruptedException ex) { ... handle ...}
                }
              }

              class EmptyingLoop implements Runnable {
                public void run() {
                  DataBuffer currentBuffer = initialFullBuffer;
                  try {
                    while (currentBuffer != null) {
                      takeFromBuffer(currentBuffer);
                      if (currentBuffer.isEmpty())
                        currentBuffer = exchanger.exchange(currentBuffer);
                    }
                  } catch (InterruptedException ex) { ... handle ...}
                }
              }

              void start() {
                new Thread(new FillingLoop()).start();
                new Thread(new EmptyingLoop()).start();
              }
            }}

Memory consistency effects: For each pair of threads that successfully exchange objects via an Exchanger, actions prior to the exchange() in each thread <i>happen-before</i> those subsequent to a return from the corresponding exchange() in the other thread.

Added in 1.5.

Java documentation for java.util.concurrent.Exchanger.

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

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to