Managing State

How to publish the state

GCUBEProvider

Import GCUBEProvider WSDL inside the Stateful WSDL:

<definitions name="Stateful" targetNamespace="http://acme.org/sample" ....
xmlns:wsdlpp="http://www.globus.org/namespaces/2004/10/WSDLPreprocessor"
xmlns:wsrp="http://docs.oasis-open.org/wsrf/2004/06/wsrf-WS-ResourceProperties-1.2-draft-01.xsd"
xmlns:provider="http://gcube-system.org/namespaces/common/core/porttypes/GCUBEProvider" />

<import namespace=http://gcube-system.org/namespaces/common/core/porttypes/GCUBEProvider   
location="../gcube/common/core/providers/GCUBEProvider.wsdl"/>

...

</definition>

Include the GCUBEProvider in the list of providers on service WSDD:

 
<parameter name="providers" value="GCUBEProvider"/>

WS-Resource Property document

Declare the WS-Resource Property document in the Stateful WSDL:

<definitions name="Stateful"
    targetNamespace="http://acme.org/sample" ...>

   <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:element name="Name" type="xsd:string"/>
                <xsd:element name="Visits" type="xsd:int"/>
        
            <xsd:element name="StatefulResourceProperties">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element ref="tns:Name" minOccurs="1" maxOccurs="1"/>
                        <xsd:element ref="tns:Visits" minOccurs="1" maxOccurs="1"/>
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element> 	
            
	</xsd:schema>
    </types>

Port-Type definitions

Extend the Stateful port-type with the GCUBEProvider and declare in the port-type definition the Resource Property document:

<portType name="StatefulPortType"
    wsrp:ResourceProperties="tns:StatefulResourceProperties"
        wsdlpp:extends="provider:GCUBEProvider">
 ...
 </portType>

Publication Profile

Provide a Publication Profile:

<ServiceGroupRegistrationParameters
    xmlns:sgc="http://mds.globus.org/servicegroup/client"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/03/addressing"
    xmlns:agg="http://mds.globus.org/aggregator/types"
    xmlns="http://mds.globus.org/servicegroup/client">


    <!-- Specifies that the registration will be renewed every 30  seconds -->
    <RefreshIntervalSecs>60</RefreshIntervalSecs>


    <!-- <Content> specifies registration specific information -->
    <Content xsi:type="agg:AggregatorContent">

        <agg:AggregatorConfig>
            <agg:GetMultipleResourcePropertiesPollType xmlns:tutorial="http://acme.org/sample">
                <agg:PollIntervalMillis>60000</agg:PollIntervalMillis>
                <agg:ResourcePropertyNames>tutorial:Name</agg:ResourcePropertyNames>
                <agg:ResourcePropertyNames>tutorial:Visits</agg:ResourcePropertyNames>
            </agg:GetMultipleResourcePropertiesPollType>
        </agg:AggregatorConfig>

        <agg:AggregatorData/>

    </Content>

</ServiceGroupRegistrationParameters>

Save the profile as registration.xml and place it in the etc folder under the service location:

|-SampleService
|--etc
|---profile.xml
|---deploy-jndi-config.xml
|---deploy-server.wsdd
|---build.properties
|---registration.xml
|
|--src
|---<omissis>
|
|--schema
|---Stateless.wsdl
|---Factory.wsdl
|---Stateful.wsdl
|
|
|--build.xml
|
|-Dependencies
|--SampleService

Include the Publication Profile resource and the RPDName (Resource Property document name) in the stateful JNDI configuration:

<jndiConfig>

    <omissis>
  <service name="acme/sample/stateful">
 	
	 <environment 
            name="RPDName"
            value="StatefulResourceProperties"
            type="java.lang.String"
            override="false"/>	
        
	<resource name="publicationProfile" type="org.gcube.common.core.state.GCUBEPublicationProfile">	
            <resourceParams>
                <parameter>
                    <name>factory</name>
                    <value>org.globus.wsrf.jndi.BeanFactory</value>
                </parameter>
                <parameter>
                    <name>mode</name>
                    <value>pull</value>
                </parameter>
                <parameter>
                    <name>fileName</name>
                    <value>registration.xml</value>
                </parameter>
            </resourceParams>
        </resource>
                 
	 <resource name="home" type="org.acme.sample.stateful.Home">
		 	<resourceParams>		                
		         <parameter>
		              <name>factory</name>
		              <value>org.globus.wsrf.jndi.BeanFactory</value>
		          </parameter>
		          <parameter>
		                <name>resourceClass</name>
		                <value>org.acme.sample.stateful.Resource</value>
		          </parameter>
		           <parameter>
                   	 	<name>persistenceDelegateClass</name>
                    	<value>org.acme.sample.stateful.ResourcePersistenceDelegate</value>
                </parameter>
		        </resourceParams>
	 </resource>
	 	
	   <environment 
		name="frequentUserLimit" 
	 	value="3" 
	 	type="java.lang.Integer"
	 	override="false" />
	</service>
</jndiConfig>

How to persist the state

The gCore Framework comes with a persistence mini-framework implementing GCUBEStatefulResource serialization and deserialization from/to some form of long-term storage. Since the most expected exploitation of the persistence is to serialise/deserialise the state of a GCUBEWSResource, the framework provides also some ready-to-use implementations of the abstract persistence delegate for GCUBEWSResource to perform file-based persistence.

GCUBEFilePersistenceDelegate

The root file-based persistence class (GCUBEFilePersistenceDelegate) is an abstract extension of a persistence delegate to add persistence to any GCUBEStatefulResource derived class. It configures the persistence storage folder as: $HOME/.gcore/persisted/$Container.ID/$ServiceName/$Resource.class/$ResourceID.extension It implements resource de/serialization by calling the Resource-specific onLoad/onStore methods It has been specialized by the following classes:

• GCUBELocalViewFilePersistenceDelegate
• GCUBELRFilePersistenceDelegate
• GCUBEWSFilePersistenceDelegate
• GCUBEWSLiteFilePersistenceDelegate

To enable the persistence of a GCUBEWSResouce, a new class extending the GCUBEWSFilePersistenceDelegate has to be created:

package org.acme.sample.stateful;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;


import org.gcube.common.core.persistence.GCUBEWSFilePersistenceDelegate;

public class ResourcePersistenceDelegate extends GCUBEWSFilePersistenceDelegate<Resource>{

	protected void onLoad(Resource resource,ObjectInputStream ois) throws Exception {		
		super.onLoad(resource,ois);
		resource.setName((String)ois.readObject());
		resource.setVisits((Integer)ois.readObject());
	}
	
	protected void onStore(Resource resource,ObjectOutputStream oos) throws Exception {		
		super.onStore(resource,oos);
		oos.writeObject(resource.getName());
		oos.writeObject(resource.getVisits());
		
	}
}

Notes:

• the class extends the GCUBEWSFilePersistenceDelegate class by parametrising the extension with the Resource class
• the class implements the onLoad() and onStore() methods
• as first step, they MUST call their super implementation
• then, they store/load the Resource class state, i.e. the Name and Visits properties' values

How to enable persistence

As most of gCore Framework facilities, GCUBEResource Persistence can be enabled by modifying the gCube Service JNDI file by declaring in the Home resource the persistence delegate class to use:

<jndiConfig xmlns="http://wsrf.globus.org/jndi/config">

 .....

 <service name="acme/sample/stateful">
 	
	 <environment 
            name="RPDName"
            value="StatefulResourceProperties"
            type="java.lang.String"
           override="false"/>	

          <resource name="home" type="org.acme.sample.stateful.Home">
		 <resourceParams>		                
		         <parameter>
		              <name>factory</name>
		              <value>org.globus.wsrf.jndi.BeanFactory</value>
		          </parameter>
		          <parameter>
		                <name>resourceClass</name>
		                <value>org.acme.sample.stateful.Resource</value>
		          </parameter>
		           <parameter>
                   	 	<name>persistenceDelegateClass</name>
                    	        <value>org.acme.sample.stateful.ResourcePersistenceDelegate</value>
                       </parameter>
		</resourceParams>
	 </resource>
   </service>
</jndiConfig>