1.1 jbpm WSDL extension implementation

1.1.1 Implementation Structure of WSDL Extension

We know that in the standard namespace (xmlns = http://schemas.xmlsoap.org/wsdl/) of WSDL, there are labels such as types, message, and porttype. However, there is also an important label in the WSDL part of the BPEL standard, that is, partnerlinktype. Partnerlinktype is an extension not included in WSDL. How does one implement these extensions in jbpm BPEL? Let's take a look at the following WSDL implementation hierarchy of jbpm BPEL: (this content is a small draft of a workflow book written by hongsoft itself. The figure cannot be sent here, sorry. It is not easy to understand here, and it is easier to understand other parts)

Javax. WSDL .* (Sun-led standard interface)

Com. IBM. WSDL .* (Implementation of the ibm wsdl Standard)

Org. jbpm. BPEL. WSDL .* (Jbpm extends WSDL)

The top layer is javax. WSDL. *, which is the interface expression of the WSDL specification formulated in JSR. It corresponds to wsdl4j. jar in jbpm's BPEL code. The second layer is com. IBM. WSDL. * is an implementation of the WSDL standard by IBM. Basically, no extensions are added. The jbpm BPEL Code corresponds to wsdl4j. jar. The bottom layer is the implementation of the jbpm extension to the WSDL part in BPEL. It uses wsdl4j. jar and then adds the parsing of the special part.

1.1.2 Extended point register

Extensionregistry is the concept of WSDL, which is used by WSDL to register a new extended vertex. In wsdl4j. jar wsdlfactoryimpl. in Java, the extensionregistry function is implemented, and jbpm adds three extension points by using the registration tool of IBM, wsdl4j. the implementation structure of jar is as follows: (this content is a small draft in a workflow book written by hongsoft itself. The figure cannot be sent here, sorry. It is not easy to understand here, and it is easier to understand other parts)

1.1.3 Extension point

One extension point registrar can register multiple extension points. A scale-out point is a new label that is not specified in the newly added WSDL standard. For example, the "BPEL erlinktype" of the BPEL is an extension point.

Three aspects need to be determined for each registered extension point:

1) in this process, you need to be able to serialize A partnerlinktype object into a corresponding XML file, which is used for transmission in the network and then deserialization in the Process of the other party. For example, the implementation of the partnerlinktype extension point is registry. registerserializer (definition. Class, wsdlconstants. Protocol, plinktypeserializer). Here plinktypeserializer is a class that extends the extensionserializer interface. The extensionserializer interface must implement the Marshall () method.

2) as described above, the other party's process needs to be able to deserialize the XML file into a partnerlinktype object. For example, the implementation of the partnerlinktype extension point is registry. registerdeserializer (definition. Class, wsdlconstants. Protocol, plinktypeserializer). Here plinktypeserializer is a class that extends the extensiondeserializer API. The extensiondeserializer interface must implement the unmarshall () method.

3) In the serialization and deserialization methods, you only need to provide the corresponding partnerlinktype object interface, and the actual use requires a specific class. The WSDL extension of BPEL implements the ing between QNAME and specific classes as follows: Registry. mapextensiontypes (definition. class, wsdlconstants. q_partner_link_type, partnerlinktypeimpl. class); partnerlinktypeimpl is a specific class that implements the partnerlinktype interface. The partnerlinktype interface is required in the Marshall () method and unmarshall () method.

1.1.4 WSDL extension points of BPEL

Jbpm adds three extensions to WSDL to implement the partnerlinktype function, property function, and propertyalias function. As shown in the table:

QNAME	Serialization	Deserialization	Ing Class
Wsdlconstants. Q_partner_link_type	Partnerlinktype Serializer	Partnerlinktype Serializer	Partnerlinktypeimpl
Wsdlconstants. Q_property	Property Serializer	Property Serializer	Propertyimpl
Wsdlconstants. Q_property_alias	Propertyalias Serializer	Propertyalias Serializer	Propertyaliasimpl

QNAME indicates "qualified name", which consists of two parts: 1) Name Space where name is located; 2) Name of the element in XML. A qname corresponds to an extension point, and the extended point Registry uses QNAME as the map of the key value to save all the extension points.

The serialization and deserialization components in jbpm both implement the extensiondeserializer, extensionserializer, and serializable interfaces at the same time, which can be implemented separately.

Ing classes are used to separate interfaces from implementations. Each ing Class corresponds to an interface, which is widely used by other parts of jbpm.