Scheduling a BPEL Process is always a requirement which many projects have. SOA11G still doesn't provide Out-of-Box, ready to use functionality for that. So we are left we a choice to use an external scheduler and from that call the SOA Process. One approach is using Quartz API, which has included lot many new features now. Another approach is to use Database based scheduler.
I personally carry this thought that - One product which Oracle has released to IT world, which is efficient, easily manageable and yet reliable is - Oracle DB. So i'll prefer Database based JOBs to try scheduling a SOA BPEL.
Here in 3 simple steps, we will create a DB JOB to schedule a BPEL which takes a STRING as input.
The input is qualified with namespace - 'http://xmlns.oracle.com/Application1/Project1/BPELProcess1', in this example.
1) Create a PLSQL procedure which will inturn call a BPEL
process using SOAP request.
CREATE OR REPLACE PROCEDURE ScheduleBPELProcess
(p_Payload IN VARCHAR2)
IS
soap_request VARCHAR2(30000);
soap_respond VARCHAR2(30000);
http_req
UTL_HTTP.REQ;
http_resp
UTL_HTTP.RESP;
resp XMLTYPE;
response VARCHAR2(30000) := '';
endpoint VARCHAR2(128) := 'http://usmtnz-dinfap19.dev.emrsn.org:8120/soa-infra/services/ETH_Temp/Project1/bpelprocess1_client_ep';
-- Service Endpoint URL of the BPEL process
BEGIN
--Create a SOAP request to invoke the BPEL process
soap_request:= ' <soap:Envelope
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">'
||'<soap:Body xmlns:ns1="http://xmlns.oracle.com/Application1/Project1/BPELProcess1">'
||' <ns1:process><ns1:input>inderpal
singh</ns1:input></ns1:process>'
||'</soap:Body>'
||'</soap:Envelope>';
http_req:= utl_http.begin_request
(
endpoint,
'POST',
'HTTP/1.1'
);
utl_http.set_header
(
http_req ,
'Content-Type' ,
'text/xml'
); -- dealing with plain text in
XML documents
utl_http.set_header(http_req ,
'Content-Length' ,
lengthb(soap_request));
utl_http.set_header(http_req ,
'SOAPAction' ,
'process'); -- required to specify a SOAP
communication
utl_http.write_text(http_req, soap_request);--
http_resp := utl_http.get_response(http_req);
utl_http.read_text(http_resp, soap_respond);
utl_http.end_response(http_resp);--
resp := XMLType.createXML(soap_respond);
IF (instr(resp.getStringVal(), 'ERROR:') > 0)
THEN
raise_application_error ( -20999, 'ScheduleBPELProcess: Failed! '||p_Payload);
END IF;
resp := resp.extract( '/soap:Envelope/soap:Body/child::node()' ,
'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"' );
END;
2) Next Step is to create a job in Oracle DB using
DBMS_SCHEDULER package.
BEGIN
-- Job defined entirely by
the CREATE JOB procedure.
DBMS_SCHEDULER.create_job
(
job_name => 'schedule_bpel_process',--Name the job
job_type => 'PLSQL_BLOCK',
job_action => 'BEGIN
ScheduleBPELProcess(''ABC''); END;',--Enclose ---the procedure name here which will be
calling the webservice
start_date => SYSTIMESTAMP,
repeat_interval => 'freq=minutely; interval=5',--The repeat interval
--attribute
value can be set according to the scheduled time.These are some --predefined
values which can be set.
end_date => NULL,
enabled => TRUE,
comments => 'Job defined entirely by the
CREATE JOB procedure.');
END;
3)We can use DBMS_SCHEDULER.setAttribute procedure to set the values of the attributes
of the job created in step 2.
For ex: Here we
can change the interval time from 5 mins to 2 mins.
BEGIN
DBMS_SCHEDULER.set_attribute (
name => 'schedule_bpel_process',
attribute => 'repeat_interval',
value => 'freq=minutely;
interval=2');
END;
TO disable the job
BEGIN
DBMS_SCHEDULER.set_attribute (
name => 'schedule_bpel_process',
attribute => ’enabled’,
value => ‘FALSE’);
END;
To drop the Job
BEGIN
DBMS_SCHEDULER.drop_job (job_name => 'schedule_bpel_process');
END;
