JP2002108688A - Gateway for mutually connecting xml environment to distributed object environment, and system using the gateway - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gateway capable of mutually connecting an Internet environment based on XML to a distributed object environment based on CORBA. SOLUTION: This system is provided with an HTTP server means for communicating with an XML server by suing an XML instance, a converting means for mutually converting the XML instance and CORBA client operation request and response, and a CORBA server means for communicating with the CORBA client by using the operation request and response. Also, this system is provided with a CORBA client means for communicating with the CORBA server by using the operation request and response, and it is more desired that the HTTP server means communicates with a XML client.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an XML (eXtensib)
le Markup Language)
CORBA (Common Object Request Broker Architect
ure) -based distributed object environment.

[0002]

2. Description of the Related Art In recent years, CORB has been used as a platform for integrating distributed applications or data.
A is spreading. On the other hand, XML attracts attention as a document description language used when communicating documents or data on the Internet.

[0003] A CORBA application is composed of a client and a server. The server has objects, and the clients use services provided by the objects on the server. For an interface of a service provided by an object, an operation and an attribute of the object, a data type, and the like are defined using IDL (Interface Definition Language). When a client calls an operation and an attribute, a target object is specified by an object reference. A pair of an object name and an object reference is managed by a naming service.

On the other hand, XML is composed of a document as a unit called an element, and is expressed using a tag including a pair of start and end. The structure of a document is expressed by layering elements. This tagged document is called an XML instance. X
An ML document is composed of an XML instance that declares an XML version or a character code, and a DTD (document type definition) that indicates a document type, in addition to an XML instance.
The DTD defines elements, attributes and entities that appear in tagged documents. In the definition of the element, the name, the order of appearance, and the number of appearances are defined.

[0005]

SUMMARY OF THE INVENTION However, XML
It was not possible to communicate with each other between the Internet environment based on CORBA and the distributed object environment based on CORBA. FIG. 1 is a configuration diagram of a conventional system.

In order to solve this problem, the present applicant has filed Japanese Patent Application No.
No. 00-68535, "Gateway for Accessing Distributed Objects Using XML"
A gateway for accessing a CORBA server from a client has been disclosed. However, the document does not disclose a method of accessing the XML server from the CORBA client, and cannot communicate with each other between the XML environment and the CORBA environment.

[0007] FIG. 2 is a diagram showing CORB via the Internet.
1 is a conventional system configuration diagram in which an A server and a client communicate. According to FIG. 2, CORBA is applied to the back end of the WWW server. A PC terminal, which is a personal computer, first downloads an applet and operates a CORBA client and server on a browser. Then, the PC terminal returns to the backend C
Access the ORBA application directly or
Alternatively, the service has been provided by starting a program from the back end side or the like.

However, in many cases, a firewall often opens an HTTP port but does not open an IIOP port, and in the system shown in FIG. 2, it may be difficult to pass data. Also, CORB
A execution program includes ORB or AWT (Abstract Wi
(ndow Toolkit) and the like, and the required memory capacity increases, so that it may be difficult to execute the process on a mobile terminal or a terminal having a low processing capability such as a PDA. Furthermore, when the program of the applet to be downloaded is relatively large and the access line is narrow, the download time increases.

Accordingly, the present invention solves the above-mentioned problems, and provides an Internet environment based on XML and CORB.
It is an object of the present invention to provide a gateway which enables mutual communication with a distributed object environment based on A.

[0010]

According to the present invention, there is provided a gateway comprising: an HTTP processing unit for communicating with an XML server using an XML instance; and a conversion unit for converting the XML instance and a CORBA operation request and response between each other. , CORB using the CORBA operation request and response
CORBA server means for communicating with the A client.

According to another embodiment of the present invention, CORB
A further comprising CORBA client means for communicating with the CORBA server using the A operation request and response,
More preferably, the TP processing means further communicates with the XML client. This enables interconnection between an XML-based Internet environment and a CORBA-based distributed object environment.

According to another embodiment of the present invention, the conversion means converts the interface definition in which the service provided by the object of the CORBA server is defined by the interface definition language, and the document type definition representing the type of the XML instance. It is also preferred to have

According to the system of the present invention, the gateway described above is provided in both the CORBA server and the CORBA client, and communication between the CORBA server and the CORBA client is performed via an IP network using an XML instance. Configured to be performed. As a result, data can be passed through a firewall that does not open the IIOP port, and there is no need to download an applet on the client side.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 is a system configuration diagram using a gateway according to the present invention. According to FIG. 3, mutual communication is possible between the CORBA server and the XML client and between the XML server and the CORBA client.

FIG. 4 is an explanatory diagram of a protocol form of a system using a gateway according to the present invention. CORB
The gateway uses HTTP (Hypertext Transfer Protocol) so that the A client can access the XML server and the XML client can access the CORBA server.
l) the XML instance transferred using
The operation request and response of the IIOP (Internet Inter-ORB Protocol) of BA are mutually converted. The CORBA client transmits and receives a CORBA operation request and response corresponding to IDL, and the XML client transmits and receives an XML instance corresponding to IDL.

Table 1 shows the correspondence rules between the CORBA data type and XML. Table 2 shows an example of association with XML based on the association rules in Table 1. FIG.
Is an example of the correspondence between the IDL definition and the DTD according to the present invention. In order to access the existing CORBA server without any change, the gateway defines an XML instance used for accessing the CORBA server in correspondence with each interface provided by the CORBA server.

[0018]

[Table 1]

[0019]

[Table 2]

According to FIG. 5, a module ("Example") is defined in a document, and an interface ("Account" or the like) is defined for the element. The interface element is the name of the object
("cos_naming"), operation request / response ("operation_ind" etc.),
It consists of attribute acquisition / setting request / response ("attriute_get_ind" etc.). Further, the operation elements are composed of elements such as operation names, argument names, data type names and values. The data type of CORBA is expressed as a tag indicating the type and a text based on PCDATA indicating the value.

Such a conversion rule is based on IDL to DTD.
Is preferably used. The gateway needs to correspond to various CORBA server objects, but only generates a DTD using a translator when a new IDL definition occurs. Further, the DTD is published on the Web for each module, so that the client can use the XML when creating the XML and the gateway can use the XML when verifying the XML instance. This allows the gateway to use various C
Flexible support for ORBA servers.

FIG. 6 is a configuration diagram of a gateway according to the present invention. The gateway includes an HTTP processing unit for communicating with the client using the XML instance, an XML parser unit for analyzing a parsed result of the received XML document, and mutually converting the XML instance and a CORBA server operation request and response. Operation / attribute conversion unit to perform
It has a CORBA client unit for communicating with the CORBA server using the operation request and response, and a CORBA server unit for communicating with the CORBA client using the operation request and response.

The gateway uses the parameter values passed in the XML instance or the CORBA's DII (dynamic start interface), DSI (dynamic skeleton interface) and IFR (interface repository) to define the target IDL definition. The system is configured to be able to cope with any change without changing the program. still,
In the implementation of the gateway, Web using Java Servlet
In addition to being an application, use XML Parser for Java made by IBM as an XML parser.

In the client, the server, and the gateway, a translator for automatically converting an IDL to a DTD is prepared to facilitate creation and verification of an XML instance, and the gateway publishes the converted DTD.

The processing sequence of the gateway when accessing the CORBA server from the HTTP client is shown below. For access from HTTP client, HT
The TP processing unit notifies the received XML instance to the XML parser unit. The XML parser performs verification and parsing using DTD. The operation / attribute conversion unit is called every time an element handler (XMLParser for Java manufactured by IBM) is activated in the XML parser unit, and converts an operation or a parameter defined in the XML instance into a format for calling the CORBA server. The CORBA processing unit obtains a reference of the object to be processed by the naming service. This makes it possible to access a specific CORBA server from a client using XML. Further, referring to an IFR (interface repository) and supplementing data necessary for parameter setting, etc., the DI
Call I to send an operation request to the CORBA server. The CORBA processing unit receives the operation response from the CORBA server, and the operation / attribute conversion unit converts and receives the DOM (Doc).
After setting the value of the "umet Object Model", the XML parser converts the DOM into an XML instance. The HTTP processing unit transmits the XML instance created above to the HTTP server.

The processing of the gateway when accessing the XML server from the CORBA client is basically the reverse of the sequence described above. That is, the CORBA processing unit receives the CORBA operation request via the DSI (dynamic skeleton interface),
After setting the value in OM, an XML instance is created in the XML parser section, and the HTTP instance is used to create the XML instance.
Perform processing to send to client.

The unilateral notification from the CORBA server can be sent to the HTTP client by the HTTP server means via the CORBA client means and the conversion means.

FIG. 7 shows an application example of the gateway described in claim 4. FIG. 8 is a system configuration diagram of the present invention that solves the problem of the system of FIG. According to FIG. 8, a gateway is applied to a back-end CORBA client and a server, and an XML over HTTP is used as an interconnecting procedure on the Internet. For the PC terminal, not only is the download of the applet unnecessary, but also because of the text processing based on XML,
There is an effect that the processing load is reduced at high speed. Furthermore, the use of HTTP facilitates the passage through a firewall.

With respect to the above-described various embodiments of the present invention, those skilled in the art can easily make various changes, modifications, and omissions of the scope of the technical idea and viewpoint of the present invention. The foregoing description is merely an example, and is not intended to be limiting. The invention is limited only as defined by the following claims and equivalents thereof.

[0030]

As described above in detail, according to the gateway of the present invention, interconnection is possible between the Internet environment based on XML and the distributed object environment based on CORBA. IDL definition and DTD
Since the association with the object is defined, it has versatility that can correspond to various objects.

Further, the gateway according to the present invention is
By providing the server and the CORBA client and communicating via the Internet using XML, the II
It can pass through a firewall that does not open the OP port, and there is no need to download an applet on the client side.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a conventional system.

FIG. 2 shows a CORBA server and C via the Internet
FIG. 2 is a conventional system configuration diagram for performing communication with an ORBA client.

FIG. 3 is a system configuration diagram using a gateway according to the present invention.

FIG. 4 is an explanatory diagram of a protocol form of a system using a gateway according to the present invention.

FIG. 5 is an example of a conversion rule between an IDL definition and XML according to the present invention.

FIG. 6 is a configuration diagram of a gateway according to the present invention.

FIG. 7 is an application diagram of the gateway shown in claim 4;

FIG. 8 is a system configuration diagram of the present invention that solves the problem of the system of FIG. 2;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Oda 2-1-1-15 Ohara, Kamifukuoka-shi, Saitama F-term in Kaididi Laboratory Co., Ltd. (Reference) 5B082 GA02 GA06 5B089 GA11 GA31 GB03 HB05 JB01 KF04

Claims (4)

[Claims] 1. An HTTP processing means for communicating with an XML server using an XML instance, a conversion means for mutually converting the XML instance and a CORBA operation request and response, and using the CORBA operation request and response. CORBA for communicating with CORBA clients
A gateway interconnecting an XML environment and a distributed object environment, comprising a server means. 2. The communication apparatus according to claim 1, further comprising a CORBA client means for communicating with a CORBA server using said CORBA operation request and response, wherein said HTTP processing means further comprises X
2. The communication device according to claim 1, wherein the communication device communicates with an ML client.
The gateway described in. 3. The conversion means includes: an interface definition that defines a service provided by an object of the CORBA server by an interface definition language;
3. The gateway according to claim 1, further comprising a conversion rule with a document type definition representing a type of the ML instance. 4. The CORBA server according to claim 1, further comprising:
A, provided between the CORBA server and the CORBA client.
A system configured to occur over an IP network using an instance.