Prepared for JSR-224 F2F meeting Proposed...

Copyright © 2004 NTT DATA Corporation

Prepared for JSR-224 F2F meeting

Proposed Architecture for Asynchronous Web Services

in JAX-RPC 2.0

March 11th, 2004

Toshiyuki KIMURAR&D Headquarters

NTT DATA Corporation

2

What's the need for Async Web Services ?

ＷｅｂＷｅｂ ServiceServiceClient impl.Client impl.

Blocks future Blocks future processingprocessing

ＷｅｂＷｅｂ Service Service impl.impl.

ClientClient SOAP ServerSOAP Server

■ Synchronous Web Services by using HTTP

Just 1 HTTP Just 1 HTTP connectionconnection

RequestRequest

ResponseResponse

Unsuitable for long-term processon server-side

Unsuitable for Unsuitable for longlong--term processterm processon serveron server--side

○ Easy to build a service end-point and client.

× Blocking stuff gives us unwelcome eventson both client-side and server-side. side

3

What's the Async Web Services ?

■ Types of Async Web Services

■ Callback type （Push)

■ Polling type (Pull)• “Request” and “Response” are transferred

by over two different HTTP connections.

• The result is picked up by the client with

several times of polling.

• “Request” and “Response” are transferred

by two different HTTP connections.

• The result is pushed back by server-sidewhen the request has been completed.

4

How to implement Async Web Services ?

Polling type of Async Web Services

J2EE PlatformJ2EE Platform

Web containerWeb container


JMSJMS EJB containerEJB container

DBMS／EIS


※※ MDB (MessageMDB (Message--Driven Bean)Driven Bean)

※※ JMS (Java Message Service)JMS (Java Message Service)

※※ SLSB (Stateless Session Bean) SLSB (Stateless Session Bean)

MDBMDB

SLSBSLSB

Queue/

Topic

Queue/

Topic

ＷｅｂＷｅｂ serviceserviceClient impl.Client impl.

JAX-RPCJAXJAX--RPCRPCJAX-RPCJAXJAX--RPCRPC

EndEnd--pointpoint

InvokeInvokeInvoke

Receive IDReceive IDReceive ID

Get resultGet resultGet result

Issue 1: Server load-up

Issue 2: Difficulty of client impl.

Order requestOrder request

Get resultGet result

5


ＷｅｂＷｅｂ Service impl.Service impl.ＷｅｂＷｅｂ Service client impl.Service client impl.

　　　　

Web ServiceWeb ServiceWeb Service

Control info DB

AA

BBCC



<<asyncWorkflow> asyncWorkflow> 　　<asyncStaticParam><asyncStaticParam>

　　<firstInteval><firstInteval>36003600</firstInterval></firstInterval>　　<iterateInterval><iterateInterval>360360</iterateInterval></iterateInterval>

<timeoutInterval><timeoutInterval>100000100000</timeoutInterval></timeoutInterval><maxRetryCount>50</maxRetryCount><maxRetryCount>50</maxRetryCount>

</asyncStaticParam></asyncStaticParam><asyncWorkflow><asyncWorkflow>

Measure of issue-1, Server load-upServer sends control info for poll-timing to clients

Server gets the initiative to control its QoS.Server gets the initiative to control its QoS.Server gets the initiative to control its QoS.

6

Measure for issue-2, difficulty of client impl.Create a utility layer for Async Web Services

ClientClient


ＷｅｂＷｅｂ ServiceServiceClient impl.Client impl.

JAX-RPCJAXJAX--RPCRPC

SOAP ServerSOAP Server


JAX-RPCJAXJAX--RPCRPC

ＷｅｂＷｅｂ Service impl.Service impl.

Utility layerUtility layer

InvokeInvokeInvoke

Get resultGet resultGet result

AP

Is (Syn

c/A

sync)

AP

Is (Syn

c/A

sync)

Main controllerMain controller

TimerTimermangermanger

Control infoControl infomanagermanager

Status mangerStatus manger

7

Feasibility Study of Async Web Services

Ｊ２ＥＥＪ２ＥＥ PlatformPlatform

Com. layerCom. layer

Sync APISync API

Client impl.Client impl.

Com. layerCom. layer

Web ServiceWeb Service

AXISAXISAXISAXIS


Async APIAsync API

WorkflowWorkflowcontrolcontrol

EnhancedEnhanced[Legend] ExistingExisting

8

The result of the Feasibility Study (1/4)Benefit #1

//処理要求用の設定

Servcie service = new Service(serviceName);

Call call = service.createCall();

call.setOperationName(startOperationName);

call.addParameter("in0", XMLType.XSD_STRING,ParameterMode.IN);

call.addParameter("in1", XMLType.XSD_LONG,ParameterMode.IN);

call.setReturnType(XSD_ANY);

call.setTargetEndpointAddress(endpointURL);

call.setMaintainSession(true);

call.invoke(new Object[]{"HELLO", new Integer(10)});//処理要求呼び出し

//パーサの準備

try{

DocumentBuilderFactory d = DocumentBuilderFactory.newInstance();

DocumentBuilderFactory factory = new org.apache.xerces.jaxp.DocumentBuilderFactoryImpl();

boolean isValidate = true;

factory.setValidating(isValidate);

factory.setNamespaceAware(true);

factory.setAttribute("http://apache.org/xml/features/validation/schema" ,new Boolean(true));

builder = factory.newDocumentBuilder();

builder.setErrorHandler(new ValidationErrorHandler());

}catch(ParserConfigurationException e){

throw new InternalException(e);

}

//ヘッダ要素の抽出開始

MessageContext msgContext = call.getMessageContext();

Message msg = (Message)msgContext.getMessage();

SOAPEnvelope envelope = msg.getSOAPEnvelope();

SOAPHeaderElement asyncSOAPHeader = envelope.getHeaderByName(Constants.ASYNCSOAP_NS,Constants.ASYNCSOAPHEADER_LOCAL);

MessageElement asyncSOAPElement = (MessageElement)asyncSOAPHeader.getChildren().get(0);

Document headerDoc = asyncSOAPElement.getAsDocument();

String headerString = new XMLUtils().DocumentToString(headerDoc);

ByteArrayInputStream headerStream = new ByteArrayInputStream(headerString.getBytes());

builder.parse(headerStream);//パース

headerStream.close();

//ステータスを取得

Element asyncServerStatusElement = (Element)headerDoc.getElementsByTagNameNS(Constants.ASYNCSOAP_NS, Constants.ASYNCSERVERSTATUS_LOCAL).item(0);

Element asyncWorkflowElement =(Element)headerDoc.getElementsByTagNameNS(Constants.ASYNCSOAP_NS, Constants.ASYNCWORKFLOW_LOCAL).item(0);

String statusCode = asyncServerStatusElement.getElementsByTagName(Constants.STATUSCODE_LOCAL).item(0).getFirstChild().getNodeValue();

String statusString = asyncServerStatusElement.getElementsByTagName(Constants.STATUSSTRING_LOCAL).item(0).getFirstChild().getNodeValue();

Element detail = (Element)asyncServerStatusElement.getElementsByTagName(Constants.DETAIL_LOCAL).item(0);

NodeList asyncStaticParamNodeList = headerDoc.getElementsByTagName(Constants.ASYNCSTATICPARAM_LOCAL);

//静的パラメータを取得

Element asyncStaticParamElement = (Element)asyncStaticParamNodeList.item(0);

Text firstIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.FIRSTINTERVAL_LOCAL).item(0).getFirstChild();

long firstInterval = Long.parseLong(firstIntervalText.getNodeValue());

Text iterateIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.ITERATEINTERVAL_LOCAL).item(0).getFirstChild();

long iterateInterval = Long.parseLong(iterateIntervalText.getNodeValue());

Text timeoutIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.TIMEOUTINTERVAL_LOCAL).item(0).getFirstChild();

long timeoutInterval = Long.parseLong(timeoutIntervalText.getNodeValue());

Text maxRetryCountText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.MAXRETRYCOUNT_LOCAL).item(0).getFirstChild();

int maxRetryCount = Integer.parseInt(maxRetryCountText.getNodeValue());

//ポーリング用の準備

Call pollingCall = service.createCall();

pollingCall.setOperationName(endOperationName);

pollingCall.setReturnType(XSD_STRING);

//第一回目のポーリングまで待機

Thread.sleep(firstInterval * 1000);//待機

//ポーリングのループ開始

boolean completed = false;//処理完了フラグ

int loop_count = 0;

while(completed){//処理が完了するまでループ

Object ret = pollingCall.invoke(new Object[]{"HELLO", new Integer(10)});//結果確認呼び出し

loop_count++;










builder.parse(headerStream);


//パラメータの抽出






//ステータスの確認

if(!statusCode.equals("RUNNING")){

completed = true;

}

//最大リトライ数のチェック

if(loop_count >= maxRetryCount){

throw new Exception("最大ポーリング回数を超過しました.");

}

Thread.sleep(iterateInterval * 1000);

}

//結果の表示

System.out.println("return : " + ret);

//処理要求用の設定

Servcie service = new Service(serviceName);


call.setOperationName(startOperationName);

call.addParameter("in0", XMLType.XSD_STRING,ParameterMode.IN);

call.addParameter("in1", XMLType.XSD_LONG,ParameterMode.IN);

call.setReturnType(XSD_ANY);


call.setMaintainSession(true);

call.invoke(new Object[]{"HELLO", new Integer(10)});//処理要求呼び出し

//パーサの準備

try{

DocumentBuilderFactory d = DocumentBuilderFactory.newInstance();

DocumentBuilderFactory factory = new org.apache.xerces.jaxp.DocumentBuilderFactoryImpl();

boolean isValidate = true;

factory.setValidating(isValidate);

factory.setNamespaceAware(true);

factory.setAttribute("http://apache.org/xml/features/validation/schema" ,new Boolean(true));

builder = factory.newDocumentBuilder();

builder.setErrorHandler(new ValidationErrorHandler());

}catch(ParserConfigurationException e){

throw new InternalException(e);

}










builder.parse(headerStream);//パース


//ステータスを取得






NodeList asyncStaticParamNodeList = headerDoc.getElementsByTagName(Constants.ASYNCSTATICPARAM_LOCAL);

//静的パラメータを取得

Element asyncStaticParamElement = (Element)asyncStaticParamNodeList.item(0);

Text firstIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.FIRSTINTERVAL_LOCAL).item(0).getFirstChild();

long firstInterval = Long.parseLong(firstIntervalText.getNodeValue());

Text iterateIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.ITERATEINTERVAL_LOCAL).item(0).getFirstChild();

long iterateInterval = Long.parseLong(iterateIntervalText.getNodeValue());

Text timeoutIntervalText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.TIMEOUTINTERVAL_LOCAL).item(0).getFirstChild();

long timeoutInterval = Long.parseLong(timeoutIntervalText.getNodeValue());

Text maxRetryCountText = (Text)asyncStaticParamElement.getElementsByTagName(Constants.MAXRETRYCOUNT_LOCAL).item(0).getFirstChild();

int maxRetryCount = Integer.parseInt(maxRetryCountText.getNodeValue());

//ポーリング用の準備

Call pollingCall = service.createCall();

pollingCall.setOperationName(endOperationName);

pollingCall.setReturnType(XSD_STRING);

//第一回目のポーリングまで待機

Thread.sleep(firstInterval * 1000);//待機

//ポーリングのループ開始

boolean completed = false;//処理完了フラグ

int loop_count = 0;

while(completed){//処理が完了するまでループ

Object ret = pollingCall.invoke(new Object[]{"HELLO", new Integer(10)});//結果確認呼び出し

loop_count++;










builder.parse(headerStream);


//パラメータの抽出






//ステータスの確認

if(!statusCode.equals("RUNNING")){

completed = true;

}

//最大リトライ数のチェック

if(loop_count >= maxRetryCount){

throw new Exception("最大ポーリング回数を超過しました.");

}

Thread.sleep(iterateInterval * 1000);

}

//結果の表示

System.out.println("return : " + ret);

BeforeBefore// ポーリングによる実装例

ServiceFactory factory = ServiceFactory.newInstance();

Service service = ServiceFactory.createService(serviceName);


call.setOperationName(new QName(targetNS, operationName));


call.addParameter("in0", XMLType.XSD_STRING, ParameterMode.IN);

call.addParameter("in1", XMLType.XSD_LONG, ParameterMode.IN);

call.setReturnType(XMLType.XSD_STRING);

call.setOperationModel(OperationModel.ASYNC_PULL);

call.invokeAsync(new Object[]{inputData});

long pollingInterval = 2000;

AsyncStatus status = call.getAsyncStatus();

while(status.isRunnging()){

Thread.sleep(pollingInterval);

status = call.getAsyncStatus();

}

String ret = (String)call.getAsyncReturnValue();

System.out.println(ret);

// ポーリングによる実装例

ServiceFactory factory = ServiceFactory.newInstance();

Service service = ServiceFactory.createService(serviceName);


call.setOperationName(new QName(targetNS, operationName));


call.addParameter("in0", XMLType.XSD_STRING, ParameterMode.IN);

call.addParameter("in1", XMLType.XSD_LONG, ParameterMode.IN);

call.setReturnType(XMLType.XSD_STRING);

call.setOperationModel(OperationModel.ASYNC_PULL);

call.invokeAsync(new Object[]{inputData});

long pollingInterval = 2000;

AsyncStatus status = call.getAsyncStatus();

while(status.isRunnging()){

Thread.sleep(pollingInterval);

status = call.getAsyncStatus();

}

String ret = (String)call.getAsyncReturnValue();

System.out.println(ret);

AfterAfter

75 lines75 lines Just 17 linesJust 17 lines

Reduces user implementationabout 4.5 times.

Reduces user implementationReduces user implementationabout 4.5 times.about 4.5 times.

9


Syn

c/A

sync In

terfac

eSyn

c/A

sync In

terfac

e

ClientClient

ＷｅｂＷｅｂ ServiceServiceClient impl.Client impl. JAXJAX--RPC 1.0, 1.1RPC 1.0, 1.1

Call . Invoke ()Call . Invoke ()Call . Invoke ()

Call . invokeOneWay ()Call . invokeOneWay ()Call . invokeOneWay ()

{ Call . invokeAsync () } ?{ { Call . invokeAsync () Call . invokeAsync () } ?} ?

JAXJAX--RPC 2.0RPC 2.0

SyncSyncSync

One-wayOneOne--wayway

AsyncAsyncAsync

An asynchronous invocation will be possible at the usage according to the existing synchronous type API.

An asynchronous invocation will be possible at the usage An asynchronous invocation will be possible at the usage according to the existing synchronous type API.according to the existing synchronous type API.

10


ＷｅｂＷｅｂ service impl.service impl.ＷｅｂＷｅｂ Service client impl.Service client impl.

Syn

c/A

sync In

terfac

eSyn

c/A

sync In

terfac

e

Async APIAsync APIAsync API

Callback APICallback APICallback API

Polling APIPolling APIPolling API

Sync WSSync WSSync WS

Polling WSPolling WSPolling WS


The access model of API layer and transport layeris separated, completely.

The access model of API layer and transport layerThe access model of API layer and transport layeris separated, completely.is separated, completely.

11

The result of the Feasibility Study (4/4)

Server gets the initiative to control its QoS.Server gets the initiative to control its QoS.Server gets the initiative to control its QoS.


ＷｅｂＷｅｂ Service impl.Service impl.ＷｅｂＷｅｂ Service client impl.Service client impl.

　　　　

Web ServiceWeb ServiceWeb Service

Control info DB

AA

BBCC



<<asyncWorkflow> asyncWorkflow> 　　<asyncStaticParam><asyncStaticParam>

　　<firstInteval><firstInteval>36003600</firstInterval></firstInterval>　　<iterateInterval><iterateInterval>360360</iterateInterval></iterateInterval>

<timeoutInterval><timeoutInterval>100000100000</timeoutInterval></timeoutInterval><maxRetryCount>50</maxRetryCount><maxRetryCount>50</maxRetryCount>

</asyncStaticParam></asyncStaticParam><asyncWorkflow><asyncWorkflow>

Benefit #4

12

Conclusion

■ Three levels to support asynchronous Web Services

■ Level1: Client-side only(Microsoft has already supported it as “Delegate”.)

■ Level2: Both Client-side and Server-sideexcept the poll timing control(Some of vendors has tried to support it in their ownproducts by the original way.)

■ Level3: Both Client-side and Server-sidewith the poll timing control(This is my proposal.)

13

ー　The　End　－

Thank you for your attention.

Prepared for JSR-224 F2F meeting Proposed...

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