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Datatype Channel

This page explains how you can implement a sample scenario of Datatype Channel EIP using WSO2 Micro Integrator.

Introduction to Datatype Channel

This EIP creates a separate channel for each type of data so that all messages on a given channel contain the same data type. The sender, knowing the data type, selects the appropriate channel to send the message. The receiver identifies the data type of a message based on the channel it is received on.

Info

For more information, go to Data Type Channel.

Data type solution

Sample scenario

The example scenario depicts a Stock Quote service deployed in an Axis2 server. It offers several service operations to the user. WSO2 MI uses the switch mediator to identify each action specified by the sender and diverts the request into the appropriate sequence. Each sequence acts as a separate channel. The sender experiences the decomposition of channels through a log message indicated by the system. There will be a different log message for each operation the sender requests.

The diagram below shows how to simulate the example scenario using the WSO2 MI.

Data type channel

Before digging into implementation details, let's take a look at the relationship between the example scenario and the Datatype Channel EIP by comparing their core components.

Datatype Channel EIP (Figure 1) Datatype Channel Example Scenario (Figure 2)
Sender Client
Datatype Channel Switch and Sequence mediators specify which datatype channel to use. The Switch Mediator determines the appropriate datatype channel, and each datatype channel is defined as a Sequence Mediator.
Receiver Stock Quote Server Instance

Synapse configuration of the artifacts

Note

When you unzip the ZIP file you downloaded below in step 7 when simulating the sample scenario, you can find the below configurations in the <UNZIPPED_FILE>/src/main/wso2mi/artifacts directory. For more information about these artifacts, go to Develop Integration Solutions.

<?xml version="1.0" encoding="UTF-8"?>
<proxy name="datatype-channel-proxy" startOnLoad="true" transports="http https" xmlns="http://ws.apache.org/ns/synapse">
    <target>
        <inSequence>
            <switch source="get-property('Action')">
                <case regex="/*urn:getQuote/*">
                    <sequence key="StockQuote"/>
                </case>
                <case regex="/*urn:getFullQuote/*">
                    <sequence key="FullQuote"/>
                </case>
                <case regex="/*urn:getMarketActivity/*">
                    <sequence key="MarketActivity"/>
                </case>
                <default>
                </default>
            </switch>
            <respond/>
        </inSequence>
    </target>
</proxy>

<?xml version="1.0" encoding="UTF-8"?>
<sequence name="FullQuote" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
    <log level="custom">
        <property name="Messaging_Channel" value="FULL_QUOTE"/>
    </log>
    <call>
        <endpoint key="StockQuoteReceiver"/>
    </call>
</sequence>

<?xml version="1.0" encoding="UTF-8"?>
<sequence name="MarketActivity" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
    <log level="custom">
        <property name="Messaging_Channel" value="MARKET_ACTIVITY"/>
    </log>
    <call>
        <endpoint key="StockQuoteReceiver"/>
    </call>
</sequence>

<?xml version="1.0" encoding="UTF-8"?>
<sequence name="StockQuote" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
    <log level="custom">
        <property name="Messaging_Channel" value="STOCK_QUOTE"/>
    </log>
    <call>
        <endpoint key="StockQuoteReceiver"/>
    </call>
</sequence>

<?xml version="1.0" encoding="UTF-8"?>
<endpoint name="StockQuoteReceiver" xmlns="http://ws.apache.org/ns/synapse">
    <address uri="http://localhost:9000/services/SimpleStockQuoteService"/>
</endpoint>

How the implementation works

Let's investigate the elements of the configuration in detail.

  • Endpoint: Defines an endpoint referenced by a name that contains an <address> element with the endpoint address of a particular service.
  • Sequence: The Sequence Mediator defines a sequence block, callable by its key (defined in the name attribute). Each sequence block has its own <in> and <out> blocks.
  • Switch: A Switch mediator that uses the get-property XPath expression to find the Action field from the SOAP header. The regular expression defined in the Regex attribute tries to match the value in the Action field. If successfully matched, it calls the relevant sequence by its key. If get-property('Action') returns urn:getQuote, the StockQuote sequence is called.

Set up the sample scenario

Follow the below instructions to simulate this sample scenario.

  1. Install WSO2 Micro Integrator.

    Info

    Follow the Install the Micro Integrator Runtime documentation for more information.

  2. Launch Visual Studio Code with the Micro Integrator for VS Code extension (MI for VS Code) installed.

    Info

    Follow the Install Micro Integrator for VS Code documentation for a complete installation guide.

  3. Download the backend service.

  4. Extract the downloaded zip file.

  5. Open a terminal, and navigate to the axis2Server/bin/ directory inside the extracted folder.

  6. Execute the following command to start the axis2server with the SimpleStockQuote backend service:

    sh axis2server.sh

    axis2server.bat

  7. Download the artifacts of the sample.

    Download ZIP

  8. Import the artifacts to WSO2 MI.

    Click File -> Open Folder -> Select the extracted ZIP file to import the downloaded ZIP file.

  9. Start the project in the WSO2 MI server.

    For instructions, go to Build and Run Documentation.

  10. Start SoapUI.

    For instructions on downloading and starting, go to SoapUI Getting Started Documentation.

Execute the sample

Send the following request using SoapUI (or any other Soap client).

POST http://localhost:8290/services/datatype-channel-proxy

Accept-Encoding: gzip,deflate
Content-Type: text/xml;charset=UTF-8
SOAPAction: "urn:getQuote"
Connection: Keep-Alive

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ser="http://services.samples" xmlns:xsd="http://services.samples/xsd">
   <soapenv:Body>
      <ser:getQuote>
         <ser:request>
            <xsd:symbol>IBM</xsd:symbol>
         </ser:request>
      </ser:getQuote>
   </soapenv:Body>
</soapenv:Envelope>

Analyze the output

Client Console output :

<?xml version='1.0' encoding='UTF-8'?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Header/>
    <soapenv:Body>
        <ns:getQuoteResponse xmlns:ns="http://services.samples">
            <ns:return xmlns:ax21="http://services.samples/xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ax21:GetQuoteResponse">
                <ax21:change>4.43961367484849</ax21:change>
                <ax21:earnings>-8.635518433323004</ax21:earnings>
                <ax21:high>-166.1948849143979</ax21:high>
                <ax21:last>168.37324107248676</ax21:last>
                <ax21:lastTradeTimestamp>Wed Aug 07 16:35:17 IST 2024</ax21:lastTradeTimestamp>
                <ax21:low>-164.8905773076009</ax21:low>
                <ax21:marketCap>1.2851652039616395E7</ax21:marketCap>
                <ax21:name>IBM Company</ax21:name>
                <ax21:open>-165.59569807034666</ax21:open>
                <ax21:peRatio>25.757171461451893</ax21:peRatio>
                <ax21:percentageChange>-2.7261040463404305</ax21:percentageChange>
                <ax21:prevClose>-162.85562103942087</ax21:prevClose>
                <ax21:symbol>IBM</ax21:symbol>
                <ax21:volume>7254</ax21:volume>
            </ns:return>
        </ns:getQuoteResponse>
    </soapenv:Body>
</soapenv:Envelope>

Axis2 server console output:

samples.services.SimpleStockQuoteService :: Generating quote for : IBM

WSO2 MI logs:

INFO {LogMediator} - {proxy:datatype-channel-proxy} Messaging_Channel = STOCK_QUOTE

Also execute the below commands, and observe the WSO2 MI log of the corresponding values MARKET_ACTIVITY, and FULL_QUOTE.

POST http://localhost:8290/services/datatype-channel-proxy

Accept-Encoding: gzip,deflate
Content-Type: text/xml;charset=UTF-8
SOAPAction: "urn:getMarketActivity"
Connection: Keep-Alive

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ser="http://services.samples" xmlns:xsd="http://services.samples/xsd">
<soapenv:Header/>
<soapenv:Body>
    <ser:getMarketActivity xmlns:ser="http://services.samples" xmlns:xsd="http://services.samples/xsd">
        <ser:request>
            <xsd:symbols>IBM</xsd:symbols>
            <xsd:symbols>MSFT</xsd:symbols>
        </ser:request>
    </ser:getMarketActivity>
</soapenv:Body>
</soapenv:Envelope>

POST http://localhost:8290/services/datatype-channel-proxy

Accept-Encoding: gzip,deflate
Content-Type: text/xml;charset=UTF-8
SOAPAction: "urn:getFullQuote"
Connection: Keep-Alive

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ser="http://services.samples" xmlns:xsd="http://services.samples/xsd">
<soapenv:Header/>
<soapenv:Body>
    <ser:getQuote>
        <ser:request>
            <xsd:symbol>IBM</xsd:symbol>
        </ser:request>
    </ser:getQuote>
</soapenv:Body>
</soapenv:Envelope>

Notice the following respective output.

Client Console outputs :

<?xml version='1.0' encoding='UTF-8'?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Header/>
    <soapenv:Body>
        <ns:getMarketActivityResponse xmlns:ns="http://services.samples">
            <ns:return xmlns:ax21="http://services.samples/xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ax21:GetMarketActivityResponse">
                <ax21:quotes xsi:type="ax21:GetQuoteResponse">
                    <ax21:change>4.40336660358583</ax21:change>
                    <ax21:earnings>12.319295187078</ax21:earnings>
                    <ax21:high>94.03619304836798</ax21:high>
                    <ax21:last>90.82348202396865</ax21:last>
                    <ax21:lastTradeTimestamp>Wed Aug 07 15:38:17 IST 2024</ax21:lastTradeTimestamp>
                    <ax21:low>93.44940381561476</ax21:low>
                    <ax21:marketCap>4.549622323611886E7</ax21:marketCap>
                    <ax21:name>IBM Company</ax21:name>
                    <ax21:open>94.6327891666243</ax21:open>
                    <ax21:peRatio>25.629335846088587</ax21:peRatio>
                    <ax21:percentageChange>-5.134415494508379</ax21:percentageChange>
                    <ax21:prevClose>-85.76178940515318</ax21:prevClose>
                    <ax21:symbol>IBM</ax21:symbol>
                    <ax21:volume>9964</ax21:volume>
                </ax21:quotes>
                <ax21:quotes xsi:type="ax21:GetQuoteResponse">
                    <ax21:change>-2.324984024729231</ax21:change>
                    <ax21:earnings>12.689150281270935</ax21:earnings>
                    <ax21:high>-76.06437403824907</ax21:high>
                    <ax21:last>78.01271422949337</ax21:last>
                    <ax21:lastTradeTimestamp>Wed Aug 07 15:38:17 IST 2024</ax21:lastTradeTimestamp>
                    <ax21:low>81.53477214299937</ax21:low>
                    <ax21:marketCap>-558317.9771472402</ax21:marketCap>
                    <ax21:name>MSFT Company</ax21:name>
                    <ax21:open>-77.27340122935652</ax21:open>
                    <ax21:peRatio>23.654158218769233</ax21:peRatio>
                    <ax21:percentageChange>3.0488952179783175</ax21:percentageChange>
                    <ax21:prevClose>-76.2566063608738</ax21:prevClose>
                    <ax21:symbol>MSFT</ax21:symbol>
                    <ax21:volume>17217</ax21:volume>
                </ax21:quotes>
            </ns:return>
        </ns:getMarketActivityResponse>
    </soapenv:Body>
</soapenv:Envelope>

<?xml version='1.0' encoding='UTF-8'?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Header/>
    <soapenv:Body>
        <ns:getFullQuoteResponse xmlns:ns="http://services.samples">
            <ns:return xmlns:ax21="http://services.samples/xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ax21:GetFullQuoteResponse">
                <ax21:tradeHistory xsi:type="ax21:TradingDay">
                    <ax21:day>0</ax21:day>
                    <ax21:quote xsi:type="ax21:GetQuoteResponse">
                        <ax21:change>-2.5198893690114956</ax21:change>
                        <ax21:earnings>13.19468975206724</ax21:earnings>
                        <ax21:high>-167.65670851883834</ax21:high>
                        <ax21:last>168.6391882596344</ax21:last>
                        <ax21:lastTradeTimestamp>Wed Aug 07 15:04:13 IST 2024</ax21:lastTradeTimestamp>
                        <ax21:low>-167.55006922799092</ax21:low>
                        <ax21:marketCap>-6712036.421688136</ax21:marketCap>
                        <ax21:name>IBM Company</ax21:name>
                        <ax21:open>175.61492125577578</ax21:open>
                        <ax21:peRatio>25.986398160281574</ax21:peRatio>
                        <ax21:percentageChange>1.52878739951175</ax21:percentageChange>
                        <ax21:prevClose>-164.82928691172327</ax21:prevClose>
                        <ax21:symbol>IBM</ax21:symbol>
                        <ax21:volume>5054</ax21:volume>
                    </ax21:quote>
                </ax21:tradeHistory>
                ........
                <ax21:tradeHistory xsi:type="ax21:TradingDay">
                    <ax21:day>364</ax21:day>
                    <ax21:quote xsi:type="ax21:GetQuoteResponse">
                        <ax21:change>4.2557370763975</ax21:change>
                        <ax21:earnings>-9.752680350379652</ax21:earnings>
                        <ax21:high>91.819438532482</ax21:high>
                        <ax21:last>87.92397844293666</ax21:last>
                        <ax21:lastTradeTimestamp>Wed Aug 07 15:04:13 IST 2024</ax21:lastTradeTimestamp>
                        <ax21:low>92.21429951895794</ax21:low>
                        <ax21:marketCap>4776036.162258254</ax21:marketCap>
                        <ax21:name>IBM Company</ax21:name>
                        <ax21:open>-86.28062478600118</ax21:open>
                        <ax21:peRatio>25.82066202297852</ax21:peRatio>
                        <ax21:percentageChange>4.353943899600255</ax21:percentageChange>
                        <ax21:prevClose>97.74441689035609</ax21:prevClose>
                        <ax21:symbol>IBM</ax21:symbol>
                        <ax21:volume>18648</ax21:volume>
                    </ax21:quote>
                </ax21:tradeHistory>
            </ns:return>
        </ns:getFullQuoteResponse>
    </soapenv:Body>
</soapenv:Envelope>

Axis2 server console outputs:

samples.services.SimpleStockQuoteService :: Generating Market activity report for : [IBM, MSFT]

samples.services.SimpleStockQuoteService :: Full quote for : IBM

WSO2 MI logs:

INFO {LogMediator} - {proxy:datatype-channel-proxy} Messaging_Channel = MARKET_ACTIVITY

INFO {LogMediator} - {proxy:datatype-channel-proxy} Messaging_Channel = FULL_QUOTE