Difference between revisions of "Adding State"
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== Delving into the implementation == | == Delving into the implementation == | ||
+ | The implementation of the stateful part of the SampleService is a bit more complex than the stateless one. The new classes will be placed in the new ''org.acme.sample.stateful''. | ||
+ | Then, the implementation has | ||
+ | |||
+ | Stateful Context | ||
+ | |||
+ | Resource | ||
+ | |||
+ | ResourceHome | ||
+ | |||
+ | Service instance port-type | ||
+ | |||
+ | Factory port-type | ||
== Configuring JNDIs & Descriptors == | == Configuring JNDIs & Descriptors == |
Revision as of 17:33, 26 March 2008
Contents
Adding State
In the first part of this tutorial we have created a stateless service for simplicity. However, the most common patterns used when developing gCube services are the ones that allow to create stateful service. In this part of the tutorial we see how to add a state to the SampleService.
Towards a multi port-type service
To add a state we need firstly to add two new port-types to the SampleService:
- one is dedicated to create a new stateful resource, the so-called Factory service port-type
- the other one is dedicated to access and manage the state, the so-called Service instance port-type
For both, we need to perform the same steps done for the Stateless port-type:
- add the port-types to the profile file
- define the WSDL interface for each port-type
- provide the Java implementation of the two port-types
plus other specific steps that allow to manage stateful services.
Profiling for the infrastructure
The following is the new SERVICE/etc/profile.xml that declares the new two port-types.
<Resource xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <ID></ID> <Type>Service</Type> <Profile> <Description>A very simple gCube Service</Description> <Class>Samples</Class> <Name>SampleService</Name> <Packages> <Main> <Description>Describes port-types</Description> <Name>Main</Name> <Dependencies> <Dependency> <Service> <Class>Samples</Class> <Name>SampleService</Name> </Service> <Package>Stubs</Package> <Version>1.0</Version> <Scope level="GHN"/> <Optional>false</Optional> </Dependency> </Dependencies> <GARArchive>org.acme.sample.gar</GARArchive> <PortType> <Name>acme/sample/stateless</Name> <WSDL/> </PortType> <PortType> <Name>acme/sample/stateful</Name> <WSDL/> </PortType> <PortType> <Name>acme/sample/factory</Name> <WSDL/> </PortType> </Main> <Software> <Description>Describes port-type stubs</Description> <Name>Stubs</Name> <Files><File>org.acme.sample.stubs.jar</File></Files> </Software> </Packages> </Profile> </Resource>
Defining the port-type interfaces
WSDL interface for the factory service
Create a new WSDL file, name it Factory.wsdl and place the file in the SERVICE/etc folder.
<definitions name="Factory" targetNamespace="http://acme.org/sample" xmlns:tns="http://acme.org/sample" xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:corefaults="http://gcube-system.org/namespaces/common/core/faults" xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/03/addressing" > <import namespace="http://gcube-system.org/namespaces/common/core/faults" location="../gcube/common/core/faults/GCUBEFaults.wsdl"/> <types> <xsd:schema targetNamespace="http://acme.org/sample"> <xsd:import namespace="http://schemas.xmlsoap.org/ws/2004/03/addressing" schemaLocation="../ws/addressing/WS-Addressing.xsd" /> <xsd:element name="logon" type="xsd:string" /> <xsd:element name="logonResponse" type="wsa:EndpointReferenceType"/> </xsd:schema> </types> <message name="logonInputMessage"> <part name="request" element="tns:logon"/> </message> <message name="logonOutputMessage"> <part name="response" element="tns:logonResponse"/> </message> <portType name="FactoryPortType"> <operation name="logon"> <input message="tns:logonInputMessage"/> <output message="tns:logonOutputMessage"/> <fault name="fault" message="corefaults:GCUBEFaultMessage"></fault> <fault name="fault" message="corefaults:GCUBEUnrecoverableFaultMessage"></fault> <fault name="fault" message="corefaults:GCUBERetrySameFaultMessage"></fault> <fault name="fault" message="corefaults:GCUBERetryEquivalentFaultMessage"></fault> </operation> </portType> </definitions>
Notes:
- the interface imports the WS-Addressing.xsd to make use of the WS-Adressing types' definitions
- the interface exposes one single operation allowing to create a new stateful resource, the logon operation
- the operation takes a string as input parameter
- the operation returns an EndpointReferenceType that points to the stateful resource
WSDL interface for the service instance
Create a new WSDL file, name it Stateful.wsdl and place the file in the SERVICE/etc folder.
<definitions name="Stateful" targetNamespace="http://acme.org/sample" xmlns:tns="http://acme.org/sample" xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:coretypes="http://gcube-system.org/namespaces/common/core/types" xmlns:corefaults="http://gcube-system.org/namespaces/common/core/faults"> <import namespace="http://gcube-system.org/namespaces/common/core/faults" location="../gcube/common/core/faults/GCUBEFaults.wsdl"/> <types> <xsd:schema targetNamespace="http://acme.org/sample"> <xsd:import namespace="http://gcube-system.org/namespaces/common/core/types" schemaLocation="../gcube/common/core/types/GCUBETypes.xsd"/> <xsd:element name="aboutSF" type="coretypes:VOID" /> <xsd:element name="aboutSFResponse" type="xsd:string" /> </xsd:schema> </types> <message name="aboutSFInputMessage"> <part name="request" element="tns:aboutSF"/> </message> <message name="aboutSFOutputMessage"> <part name="response" element="tns:aboutSFResponse"/> </message> <portType name="StatefulPortType"> <operation name="aboutSF"> <input message="tns:aboutSFInputMessage"/> <output message="tns:aboutSFOutputMessage"/> <fault name="fault" message="corefaults:GCUBEFaultMessage"></fault> </operation> </portType> </definitions>
Notes:
- the port-type exposes a single operation, the aboutSF operation
- the operation does not take any input, in these cases it must be passed an element coretypes:VOID to avoid SOAP issues
- the operation returns a string
Delving into the implementation
The implementation of the stateful part of the SampleService is a bit more complex than the stateless one. The new classes will be placed in the new org.acme.sample.stateful. Then, the implementation has
Stateful Context
Resource
ResourceHome
Service instance port-type
Factory port-type
Configuring JNDIs & Descriptors
Building & Deploying
A Test Client
--Manuele.simi 03:21, 26 March 2008 (EET)