Sequence for access token generation

simple-token-gen.xml

<?xml version="1.0" encoding="UTF-8"?>
<sequence name="simple-token-gen" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
    <property description="access_token" expression="get-property('registry', 'gov:/pizzaOrderingAPI/access_Token')" name="access_token" scope="default" type="STRING"/>
    <property description="generated_time" expression="get-property('registry','gov:/pizzaOrderingAPI/generated_Time')" name="generated-time" scope="default" type="LONG"/>
    <property description="client_credentials" name="app-client-auth" scope="default" type="STRING" value="eDU1YVdaWV9iVUJtTXY4U3IzOXJMbWdTSmZBYTpOcGNKdUdFM1JQcldlY3NQQ0wwQ2htd2xucmNh"/>
    <property expression="json-eval($)" name="message-body" scope="default" type="STRING"/>
    <property expression="get-property('axis2','REST_URL_POSTFIX')" name="resource" scope="default" type="STRING"/>
    <filter description="" xpath="get-property('SYSTEM_TIME') - get-property('generated-time') > 3600000 or get-property('access_token') = ''">
        <then>
            <payloadFactory media-type="xml">
                <format>
                    <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
                        <soapenv:Body>
                            <root xmlns="">
                                <grant_type>client_credentials</grant_type>
                            </root>
                        </soapenv:Body>
                    </soapenv:Envelope>
                </format>
                <args/>
            </payloadFactory>
            <header expression="fn:concat('Basic ', get-property('app-client-auth'))" name="Authorization" scope="transport"/>
            <header name="Content-Type" scope="transport" value="application/x-www-form-urlencoded"/>
            <property description="messageType" name="messageType" scope="axis2" type="STRING" value="application/x-www-form-urlencoded"/>
            <property description="REST_URL_POSTFIx" name="REST_URL_POSTFIX" scope="axis2" type="STRING" value=""/>
            <call blocking="true">
                <endpoint name="token">
                    <http method="post" uri-template="https://localhost:8243/token"/>
                </endpoint>
            </call>
            <property expression="get-property('resource')" name="REST_URL_POSTFIX" scope="axis2" type="STRING"/>
            <property description="generated Time Setter" expression="get-property('SYSTEM_TIME')" name="gov:/pizzaOrderingAPI/generated_Time" scope="registry" type="LONG"/>
            <property description="generated_token" expression="json-eval($.access_token)" name="generated-access-token" scope="default" type="STRING"/>
            <property description="new Token setter" expression="get-property('generated-access-token')" name="gov:/pizzaOrderingAPI/access_Token" scope="registry" type="STRING"/>
            <header expression="fn:concat('Bearer ', get-property('generated-access-token'))" name="Authorization" scope="transport"/>
            <payloadFactory media-type="json">
                <format>
					$1
	            </format>
                <args>
                    <arg evaluator="xml" expression="get-property('message-body')"/>
                </args>
            </payloadFactory>
        </then>
        <else>
            <header expression="fn:concat('Bearer ', get-property('access_token'))" name="Authorization" scope="transport"/>
        </else>
    </filter>
</sequence>