FeaturesMain goals The component SE Mapping provides a way to implement services using the design pattern Facade as following:
Concurrency Several instances of the component can be deployed concurrently on Petals ESB. So, you are able to deploy each service 'Facade' on several component instances to get high availability. |
Table of contents
Contributors
No contributors found for: authors on selected page(s)
|
Introduction
The version 1.0.x of the component provides the following transformation engines:
- XSL transformation based on Saxon HE 9.7.0-11.
Creating a service-unit
A service-unit associated to a service 'Facade' contains:
- the WSDL of your service, the one implemented by the service 'Facade',
- WSDL annotations defining:
- the transformations to apply,
- the operation of the 3PP service provider to invoke,
- the 3PP service provider to invoke, defined in the service-unit JBI descriptor as consumer section.
Creating the service contract
Write your WSDL according to your needs. No requirement about the WSDL is expected.
A best practice is to explode your WSDL in two parts:
- an abstract part containing data definition (XSD) and the service interface (port type),
- a concrete part containing the binding of the port type, and the service definition.
Annotating the WSDL
Annotations take place in each operation of the binding definition:
<binding name="FactureServicePortBinding" type="tns:FactureService"> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document" /> <operation name="stocker"> <soap:operation soapAction="" /> <mapping:service-provider-operation>ged:stocker</mapping:service-provider-operation> <mapping:input-transformation xsl="input-stocker.xsl" /> <mapping:output-transformation xsl="output-stocker.xsl"> <mapping:should-return-fault as-xpath-expr="true">false()</mapping:should-return-fault> </mapping:output-transformation> <input> <soap:body use="literal" /> </input> <output> <soap:body use="literal" /> </output> </operation> </binding>
All annotations are member of the namespace "http://petals.ow2.org/se/mapping/annotations/1.0":
- service-provider-operation defines the qualified name of the 3PP service provider operation to invoke when the current operation is invoked,
- input-transformation defines the transformation to apply on incoming requests on the current operation,
- output-transformation defines the transformation to apply on response for the current operation,
Defining input transformations
The input transformation is defined by the annotation 'input-transformation'.
Now, only XSL transformations are available.
Defining an XSL input transformation
To define an input transformation as an XSL transformation, just define the XSL style-sheet to use by the attribute 'xsl' of the annotation 'input-transformation'. The XSL style-sheet is provided as a file located in the root directory of the service unit.
<binding name="FactureServicePortBinding" type="tns:FactureService"> ... <operation name="stocker"> ... <mapping:input-transformation xsl="input-stocker.xsl" /> ... </operation> </binding>
A property defined at component level (through the component configuration parameter 'properties-file' can be accessed into the XSL through a global XSL parameter defined by the qualified name: '<property-name>' of namespace 'http://petals.ow2.org/se/mapping/xsl/param/1.0'.
For a unit test purpose, an extension of JUnit is available to test your XSL. See chapter "Unit testing". |
Defining output transformations
The output transformation is defined by the annotation 'output-transformation'.
The result of the transformation can be returned to the service consumer as a normal response or as a fault according to the result of the expression defined by the sub-annotation 'should-return-fault'. If the expression returns 'true', a fault will be returned to the service consumer, otherwise a normal response will be returned:
<binding name="FactureServicePortBinding" type="tns:FactureService"> ... <operation name="stocker"> ... <mapping:output-transformation xsl="output-stocker.xsl"> <mapping:should-return-fault as-xpath-expr="true">false()</mapping:should-return-fault> </mapping:output-transformation> ... </operation> </binding>
Now, only XSL transformations and XPath expression are available.
Defining an XSL output transformation
To define an output transformation as an XSL transformation, just define the XSL style-sheet to use by the attribute 'xsl' of the annotation 'output-transformation'. The XSL style-sheet is provided as a file located in the root directory of the service unit.
<binding name="FactureServicePortBinding" type="tns:FactureService"> ... <operation name="stocker"> ... <mapping:output-transformation xsl="output-stocker.xsl"> ... </mapping:output-transformation> ... </operation> </binding>
The incoming request can be accessed into the XSL through a global XSL parameter defined by the qualified name: 'incoming-request' of namespace 'http://petals.ow2.org/se/mapping/xsl/param/output/1.0'.
A property defined at component level (through the component configuration parameter 'properties-file' can be accessed into the XSL through a global XSL parameter defined by the qualified name: '<property-name>' of namespace 'http://petals.ow2.org/se/mapping/xsl/param/1.0'.
For a unit test purpose, an extension of JUnit is available to test your XSL. See chapter "Unit testing". |
Selecting response nature through XPath
The expression to select the response nature to return (fault or normal response) can be expressed as an XPath expression using the attribute 'as-xpath-expr' set to 'true', and giving the XPath expression as value of the annotation 'should-return-fault':
<mapping:output-transformation xsl="output-stocker.xsl"> <mapping:should-return-fault as-xpath-expr="true">false()</mapping:should-return-fault> </mapping:output-transformation>
For a unit test purpose, an extension of JUnit is available to verify your XPath expression syntax when checking your WSDL. See chapter "Unit testing". |
Defining the 3PP service provider
The 3PP service provider is defined in the service unit JBI descriptor as a service consumer:
<!-- The service invoked --> <jbi:consumes interface-name="ged:GedService" service-name="ged:GedService"> <petalsCDK:timeout>15000</petalsCDK:timeout> <petalsCDK:mep>InOut</petalsCDK:mep> </jbi:consumes>
Supported parameters of the section 'consumes' are:
- timeout, to set on the message exchange used for the service provider invocation,
- mep, is not used because we reuse the one of the incoming exchange,
- operation, is not used. As we can have a service 'Facade' providing several operations, it was needed to define the annotation 'service-provider-operation'. A warning will appear in log traces if this field is set.
- exchange-properties, the properties to set on the message exchange used to invoke the service provider,
- message-properties, the properties to set on the message of message exchange used to invoke the service provider.
Parameter | Description |
Default |
Required |
---|---|---|---|
provides | Describe the JBI service that will be exposed into the JBI bus. Interface (QName), Service (QName) and Endpoint (String) attributes are required. | - | Yes |
No specific configuration exists
Configuring the component
The component can be configured through the parameters of its JBI descriptor file. These parameters are divided in following groups:
- JBI parameters that have not to be changed otherwise the component will not work,
- CDK parameters that are parameters driving the processing of the CDK layer.
CDK parameters
The component configuration includes the configuration of the CDK. The following parameters correspond to the CDK configuration.
Parameter | Description | Default | Scope |
---|---|---|---|
acceptor-pool-size | The size of the thread pool used to accept Message Exchanges from the NMR. Once a message is accepted, its processing is delegated to the processor pool thread. | 1 |
Runtime |
acceptor-retry-number | Number of tries to submit a message exchange to a processor for processing before to declare that it cannot be processed. | 40 |
Installation |
acceptor-retry-wait | Base duration, in milliseconds, to wait between two processing submission tries. At each try, the new duration is the previous one plus this base duration. | 250 |
Installation |
acceptor-stop-max-wait | The max duration (in milliseconds) before, on component stop, each acceptor is stopped by force. | 500 |
Runtime |
processor-pool-size | The size of the thread pool used to process Message Exchanges. Once a message is accepted, its processing is delegated to one of the thread of this pool. | 10 | Runtime |
processor-max-pool-size | The maximum size of the thread pool used to process Message Exchanges. The difference between this size and the processor-pool-size represents the dynamic threads that can be created and destroyed during overhead processing time. |
50 |
Runtime |
processor-keep-alive-time | When the number of processors is greater than the core, this is the maximum time that excess idle processors will wait for new tasks before terminating, in seconds. |
300 |
Runtime |
processor-stop-max-wait | The max duration (in milliseconds) of message exchange processing on stop phase (for all processors). |
15000 |
Runtime |
time-beetween-async-cleaner-runs | The time (in milliseconds) between two runs of the asynchronous message exchange cleaner. |
2000 |
Installation |
properties-file | Name of the file containing properties used as reference by other parameters. Parameters reference the property name using a placeholder in the following pattern ${myPropertyName}. At runtime, the expression is replaced by the value of the property. The properties file can be reloaded using the JMX API of the component. The runtime configuration MBean provides an operation to reload these place holders. Check the service unit parameters that support this reloading. The value of this parameter is :
|
- | Installation |
monitoring-sampling-period | Period, in seconds, of a sample used by response time probes of the monitoring feature. |
300 |
Installation |
Definition of CDK parameter scope :
- Installation: The parameter can be set during the installation of the component, by using the installation MBean (see JBI specifications for details about the installation sequence). If the parameter is optional and has not been defined during the development of the component, it is not available at installation time.
- Runtime: The paramater can be set during the installation of the component and during runtime. The runtime configuration can be changed using the CDK custom MBean named RuntimeConfiguration. If the parameter is optional and has not been defined during the development of the component, it is not available at installation and runtime times.
Interceptor
Interceptors can be defined to inject some post or pre processing in the component during service processing.
Using interceptor is very sensitive and must be manipulate only by power users. An non properly coded interceptor engaged in a component can lead to uncontrolled behaviors, out of the standard process.
Example of an interceptor configuration:
<?xml version="1.0" encoding="UTF-8"?> <!--...--> <petalsCDK:component-interceptors> <petalsCDK:interceptor active="true" class="org.ow2.petals.myInterceptor" name="myInterceptorName"> <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param> <petalsCDK:param name="myParamName2">myParamValue2</petalsCDK:param> </petalsCDK:interceptor> </petalsCDK:component-interceptors> <!--...-->
Interceptors configuration for Component (CDK)
Parameter | Description | Default | Required |
---|---|---|---|
interceptor - class | Name of the interceptor class to implement. This class must extend the abstract class org.ow2.petals.component.common.interceptor.Interceptor. This class must be loadable from the component classloader, or in a dependent Shared Library classloader. | - | Yes |
interceptor - name | Logical name of the interceptor instance. It can be referenced to add extended parameters by a SU Interceptor configuration. | - | Yes |
interceptor - active | If true, the Interceptor instance is activated for every SU deployed on the component. If false, the Interceptor can be activated: -by the InterceptorManager Mbean at runtime, to activate the interceptor for every deployed SU. -by a SU configuration |
- | Yes |
param[] - name | The name of the parameter to use for the interceptor. | - | No |
param[] | The value of the parameter to use for the interceptor. | - | No |
Monitoring the component
Using metrics
Several probes providing metrics are included in the component, and are available through the JMX MBean 'org.ow2.petals:type=custom,name=monitoring_<component-id>', where <component-id> is the unique JBI identifier of the component.
Common metrics
The following metrics are provided through the Petals CDK, and are common to all components:
Metrics, as MBean attribute | Description | Detail of the value | Configurable |
---|---|---|---|
MessageExchangeAcceptorThreadPoolMaxSize | The maximum number of threads of the message exchange acceptor thread pool | integer value, since the last startup of the component | yes, through acceptor-pool-size |
MessageExchangeAcceptorThreadPoolCurrentSize | The current number of threads of the message exchange acceptor thread pool. Should be always equals to MessageExchangeAcceptorThreadPoolMaxSize. | instant integer value | no |
MessageExchangeAcceptorCurrentWorking | The current number of working message exchange acceptors. | instant long value | no |
MessageExchangeAcceptorMaxWorking | The max number of working message exchange acceptors. | long value, since the last startup of the component | no |
MessageExchangeAcceptorAbsoluteDurations | The aggregated durations of the working message exchange acceptors since the last startup of the component. | n-tuple value containing, in nanosecond:
|
no |
MessageExchangeAcceptorRelativeDurations | The aggregated durations of the working message exchange acceptors on the last sample. | n-tuple value containing, in nanosecond:
|
no |
MessageExchangeProcessorAbsoluteDurations | The aggregated durations of the working message exchange processor since the last startup of the component. | n-tuple value containing, in milliseconds:
|
no |
MessageExchangeProcessorRelativeDurations | The aggregated durations of the working message exchange processor on the last sample. | n-tuple value containing, in milliseconds:
|
no |
MessageExchangeProcessorThreadPoolActiveThreadsCurrent | The current number of active threads of the message exchange processor thread pool | instant integer value | no |
MessageExchangeProcessorThreadPoolActiveThreadsMax | The maximum number of threads of the message exchange processor thread pool that was active | integer value, since the last startup of the component | no |
MessageExchangeProcessorThreadPoolIdleThreadsCurrent | The current number of idle threads of the message exchange processor thread pool | instant integer value | no |
MessageExchangeProcessorThreadPoolIdleThreadsMax | The maximum number of threads of the message exchange processor thread pool that was idle | integer value, since the last startup of the component | no |
MessageExchangeProcessorThreadPoolMaxSize | The maximum size, in threads, of the message exchange processor thread pool | instant integer value | yes, through http-thread-pool-size-max |
MessageExchangeProcessorThreadPoolMinSize | The minimum size, in threads, of the message exchange processor thread pool | instant integer value | yes, through http-thread-pool-size-min |
MessageExchangeProcessorThreadPoolQueuedRequestsCurrent | The current number of enqueued requests waiting to be processed by the message exchange processor thread pool | instant integer value | no |
MessageExchangeProcessorThreadPoolQueuedRequestsMax | The maximum number of enqueued requests waiting to be processed by the message exchange processor thread pool since the last startup of the component | instant integer value | no |
ServiceProviderInvocations | The number of service provider invocations grouped by:
|
integer counter value since the last startup of the component | no |
ServiceProviderInvocationsResponseTimeAbs | The aggregated response times of the service provider invocations since the last startup of the component grouped by:
|
n-tuple value containing, in millisecond:
|
no |
ServiceProviderInvocationsResponseTimeRel | The aggregated response times of the service provider invocations on the last sample, grouped by:
|
n-tuple value containing, in millisecond:
|
no |
Dedicated metrics
No dedicated metric is available.
Receiving alerts
Several alerts are notified by the component through notification of the JMX MBean 'org.ow2.petals:type=custom,name=monitoring_<component-id>', where <component-id> is the unique JBI identifier of the component.
To integrate these alerts with Nagios, see Receiving Petals ESB defects in Nagios. |
Common alerts
Defect | JMX Notification |
---|---|
A message exchange acceptor thread is dead |
|
No more thread is available in the message exchange acceptor thread pool |
|
No more thread is available to run a message exchange processor |
|
Dedicated alerts
No dedicated alert is available.
Unit testing
The unit testing can occur at several levels in your Mapping service unit:
- to check the annotation compliance of the WSDL with the attendees of the component,
- to unit test your XSL transformations.
A dedicated framework is available as an extension of JUnit providing facilities:
- to validate your WSDL:
- in a WSDL point of view,
- checking the compliance of the WSDL with the attendees of the component,
- checking syntax of the XPath expressions,
- to verify easily the XSL style-sheets.
This dedicated framework is provided by the Maven artifact org.ow2.petals:petals-se-mapping-junit:
<project> ... <dependencies> ... <dependency> <groupId>org.ow2.petals</groupId> <artifactId>petals-se-mapping-junit</artifactId> <version>1.0.0</version> <scope>test</scope> </dependency> ... </dependencies> ... </project>
The version 1.0.0+ of the framework is compliant with the Petals SE Mapping 1.0.0+. |
Checking the compliance of the WSDL
The unit test framework contains an assertion 'assertWsdlCompliance' to verify easily the compliance of your WSDL with the attendees of the mode 'service':
import static org.ow2.petals.se.mapping.junit.Assert.assertWsdlCompliance; import javax.xml.namespace.QName; import org.junit.Test; public class WsdlComplianceTest { private static final String TARGET_NAMESPACE = "http://facture.mapping.samples.petals.ow2.org/"; @Test public void validate() throws Exception { assertWsdlCompliance( new QName[] { new QName(TARGET_NAMESPACE, "stocker"), new QName(TARGET_NAMESPACE, "consulter") }); } }
See the Javadoc for more details on parameters.
Unit-testing your XSLs
The unit test framework contains an assertion 'assertXslTransformation' to verify easily the result of your XSL transformations:
import static org.ow2.petals.se.mapping.junit.Assert.assertXslTransformation; ... import org.junit.Test; public class XslTest { private static final String XML_DIR = "xml-to-transform/"; private static final String XML_RESULT_DIR = "xml-result/"; private static final String INPUT_CONSULTER_DIR = "input-consulter/"; private static final String INPUT_CONSULTER_XML_DIR = XML_DIR + INPUT_CONSULTER_DIR; private static final String INPUT_CONSULTER_RESULT_DIR = XML_RESULT_DIR + INPUT_CONSULTER_DIR; private static final String XSL_INPUT_CONSULTER = "input-consulter.xsl"; @Test public void inputConsulter_Nominal() throws IOException, TransformerException, SAXException { assertXslTransformation(INPUT_CONSULTER_RESULT_DIR + "nominal.xml", INPUT_CONSULTER_XML_DIR + "nominal.xml", XSL_INPUT_CONSULTER); } }
See the Javadoc for more details on parameters.