net.sf.asyncobjects
Class Using<S extends ACloseable,T>

java.lang.Object
  net.sf.asyncobjects.Using<S,T>

Type Parameters:

S - Service type

T - Result type

All Implemented Interfaces:

ExplicitSharing

public abstract class Using<S extends ACloseable,T>
extends Object
implements ExplicitSharing

This is an utility class that executes some action and than closes resource that implements the interface ACloseable after activity in the body finishes.

The sample below gets output stream of the socket, writes 1,2,3 to it and closes it. The promise returned from method resolves only after output is closed.

 
      private Promise<Void> write123(ASocket socket) {
        return new Using<AByteOutput,Void>(socket.getOutput()) {
                protected Promise<Void> run(AByteOutput out) {
             // send data, result promise will resolve when data finish writing.
             // The close method on output will be called only after it rather
             // then right after return of the method.
             return out.write(BinaryData.fromBytes(new byte[]{(byte)1,byte)2,byte)3})); 
           }
        }.promise();
      }
 
 

Constructor Summary

Using(Promise<S> servicePromise)
A constructor

Using(S service)
A constructor

Method Summary

protected Promise<? extends T>	openFailed(Throwable problem) This method is called in separate turn in case when open operation failed.
Promise<T>	promise()
protected abstract Promise<? extends T>	run(S service) This method should be implemented by subclasses.

Methods inherited from class java.lang.Object

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

Constructor Detail

Using

public Using(Promise<S> servicePromise)

A constructor

Parameters:

servicePromise - a promise for service

Using

public Using(S service)

A constructor

Parameters:

service - a service proxy

Method Detail

run

protected abstract Promise<? extends T> run(S service)

This method should be implemented by subclasses.

Parameters:

service - a service that was argument of constructor

Returns:

a promise for OutType or result of OutType.

openFailed

protected Promise<? extends T> openFailed(Throwable problem)
                                   throws Throwable

This method is called in separate turn in case when open operation failed.

Parameters:

problem - a problem

Returns:

a result value will be used as result of using operation.

Throws:

Throwable - a problem

promise

public final Promise<T> promise()

Returns:

a result promise. it resolves after the body is finished and after close operation is complete. Note that if close() operation is smashed, the result promise will be smashed with problem of close operation independently of what was the result of run(ACloseable).