Abstract:
The present invention refers to the field of networked computer telecommunication, and in particular to a method and system for processing services associated with a contract between a service requester (SC) and a service provider (SP) wherein said services are to be provided via a network, wherein at least one service contract is defined between said service requester and said service provider. In order to improve the processing of web services, license management facilities ( 75 A) are included into the prior art method cooperating closely with a Contract Management component ( 74 A) and a Service Metering Component ( 76 A). Preferably, a plurality of different license types are provided for selection to be used, which may further be combined also, in order to match best the needs of a customer.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to the field of networked computer telecommunication, and in particular to a method and system for processing services associated with a contract between a service requester (SC) and a service provider (SP) wherein said services are to be provided via a network, wherein at least one service contract is defined between said service requester and said service provider.  
         [0003]     2. Description and Disadvantages of Prior Art  
         [0004]     Web services define a technique for describing software components to be accessed, methods for accessing these components, and discovery methods that enable the identification of relevant service providers. Web services are programming language-, programming model-, and system software neutral.  
         [0005]     In this regard, two prior art Web services standards are relevant. They are shortly sketched out and commented as follows in order to introduce into the problems concerned in prior art:  
         [0006]     First, the Simple Object Access Protocol (SOAP) provides a means of messaging between a service provider and a service requester. SOAP is independent of the underlying transport protocol, SOAP payloads can be carried on HTTP, FTP, JMS and other protocols.  
         [0007]      FIG. 1  gives a SOAP example carried by the HTTP POST request.  
         [0008]     HTTP messages consist of requests from client to server and responses from server to client. Both types of message (Request and Response messages) consist of a start-line, zero or more header fields (also known as “headers”), an empty line indicating the end of the header fields, and possibly a message-body.  
         [0009]     The structure of a HTTP request message is depicted in  FIG. 2 : the first line of that message specifies the method to be applied to the resource, the identifier of the resource, and the HTTP protocol version in use. The HTTP protocol defines multiple request methods like GET, HEAD, POST, PUT, DELETE, TRACE, CONNECT, OPTIONS. The method indicates the operation to be performed on the resource.  
         [0010]     The resource upon which to apply the request is identified by a Request-URI, which is a Uniform Resource Identifier. Uniform Resource Identifiers are simply formatted strings, which identify—via name, location, address or any other characteristic—a resource. For example: The well-known HTTP URL scheme used to locate network resources via the HTTP protocol contains resource-URIs. The scheme specific syntax and semantics for http URLs are 
        http_URL=“http:”“//”host[“:”port][request-uri]       
 
         [0012]     If the port is empty or not given, port  80  is assumed. The semantics are that the identified resource is located at the server listening for TCP connections on that port of that host, and the Request-URI identifies the resource. The syntax and semantics for Request-URI are 
        Request-uri=abs-_path[“?”query-string]
 
 where the abs_path is an identifier of the resource and the query string is any kind of information which can be used for processing the request. 
       
 
         [0015]     The header fields carry meta-information associated with the request or response.  
         [0016]     The message-body of an HTTP message is used to carry the entity-body associated with the request or response. The message body depicted in  FIG. 2  contains the actual SOAP message, which has a structure as given in  FIG. 3 : Inside An envelope section a number of header fields 1, . . . n are defined, which construct the so called SOAP header, which is followed by by the actual SOAP body, which comprises a second number of so called “Body fields 1, . . . n.  
         [0017]     Thus, the overall structure of a SOAP message carried over a network e.g. by a transport protocol like HTTP is depicted as a conglomeration of FIGS.  1  to  3  in  FIG. 4 .  
         [0018]      FIG. 1  gives a SOAP example carried by the HTTP POST command. The HTTP request method is POST, the resource-URI is “/StockQuote”, which is an absolute path identifying the resource for which the request is intended. The resource-URI does not contain a query string.  
         [0019]     Beside SOAP, there is in prior art the above-mentioned second relevant Web Service standard:  
         [0020]     The Web Services Description Language (WSDL) is an XML document for describing Web Services as a set of endpoint operations on messages containing either document-oriented or Remote Procedure Call (RPC) payloads. So called service interfaces are defined abstractly in terms of message structures and sequences of simple message exchanges (or “operations” in WSDL terminology). They are then bound to a concrete network protocol and data-encoding format to define an endpoint. Related concrete endpoints are bundled to define abstract endpoints (services).  
         [0021]     WSDL supports a service interface definition that is distinct from the protocol bindings used for service invocation. WSDL allows for multiple bindings for a single service. The service interface definition and the access binding are also distinct from the implementation of the functionality of the service. Service requestors usually generate client stub code for a web service from the corresponding WSDL; the WSDL of a service is usually requested from the service provider. The client stub code implements the necessary logic to create the correct message structure and the correct data encoding to address the endpoint. Since there is a distinction between definition, binding and implementation of a service, client stub codes created for a certain definition and binding can usually address various endpoints without requiring code changes, simply by using another endpoint address.  FIG. 5A  and the continuation thereof,  FIG. 5B  is given to disclose an exemplary WSDL document with further details to a person skilled in the art.  
         [0022]     An important feature of Web Services is that they are stateless, according to a request-response scheme. A stateless server is one, which treats each request as an independent transaction, unrelated to any previous request. This simplifies the server design because it does not need to allocate storage to deal with conversations in progress or worry about freeing it if a client dies in mid-transaction. A disadvantage is that it may be necessary to include more information in each request and this extra-information will need to be interpreted by the server each time.  
         [0023]     Having now described the constraints in which electronic communication of the above-mentioned kind runs, the disadvantages of prior art will be described next below:  
         [0024]     Commercial usage of web services is based on a contract concluded between the service provider and the service requester. Such contract represents an agreement about the conditions for using and provisioning web services or web applications. The contract details may specify the conditions for billing the service, i.e. the price, service levels specifying the desired quality of service in a more detailed way, and further information which is highly critical for both the service requestor and the service provider. Basically, in prior art business, there are no limitations regarding the scope of a contract or the number of contracts: one contract may contain multiple services, or one service may be contained in multiple contracts, which are all valid at the same time.  
         [0025]     In a typical prior art scenario, either two parties, ie, the Service Requester or Service Consumer, referred to herein as SC, and the Service Provider, referred to as SP, communicate, or three parties are comprised of the Web service Communication, i.e. the Service Requester, the Service provider who manages the above contracts and the Service Supplier, referred to as SS, which actually performs the service, which is sometimes hold invisible to the requester.  
         [0026]     The only disclosure of such prior art, which is thus elaborated to address the above-mentioned web services facilities is published in “IBM Web Services Toolkit” (“Emerging Technologies Toolkit”), available in the year of 2002 for a trial period of 60 days based on IBM Alphaworks license agreements.  
         [0027]     A short review on a software component as it is disclosed there, which is called “Contract Service” and comprises the most technical features relevant for the present invention is given, as follows:  
         [0028]     The Contract Service handles the relationship between service providers and service requesters. It provides information about the type of contract between a service provider and the service hub (deployment contracts, also known as provider contracts) and between a service requestor and the service hub (usage contracts). Usage contracts can be used to subscribe to any combination of operations of any service provided through the service hub. A usage contract contains information such as how calls to service operations are to be charged for (by time, by number of uses, by amount of use etc.) and how much the subscribed service operations should cost for that client. For each usage contract the Contract Service defines the payment method and rating model to be used, the effective dates for that contract. Contracts may optionally store the digital signatures of both parties (service hub and service provider/requestor) to the contract. In the Utility Service demo that is shipped with the Web Services Toolkit, contracts are added to the Contract Service via a Utility Services Portal supplied with the demo, and a valid contract must be in place between a service hub and a service requestor before the requestor can use the service.  
         [0029]     In this prior art contracting system for web services there are a number of disadvantages, introduced as follows:  
         [0030]     Web services define a technique for describing software components the execution of which may have a considerable business value for a client, they describe how such web services are accessible by the clients and they describe discovery methods that enable the identification of relevant service providers to a client. Web services are mostly programming language-, programming model-, and system software neutral. Web services as described above are of high importance for the next future because they form a key part of dynamic e-business, and in particular of e-business on demand.  
         [0031]     E-business on demand requires besides metering and accounting of services sophisticated systems to deal with the contractual relationships that have to be in place before actual on demand services can be offered to a client.  
         [0032]     There is a remarkable similarity between e-business on demand and prior art software usage: in both fields a client is ready to pay some money in order to use a piece of software the execution of which serves him to get some predefined business value. As in prior art software usage different types of licenses are known and are useful to be customised to the specific needs of a customer it would be strongly desirable also to implement a licensing facility into such prior art contract management system, which performs the web services in favour to a client. The problem is that licensing may be considered as a special case, i.e. a special way of contracting for software usage. Disadvantageously the prior art contracting systems for performing web services do not offer any licensing until now. A specific difficulty for simply implementing existing licensing business methods into electronic web service management is that the user would need a high degree of personalisation in the licences, the vendor or provider of a web service cannot implement in program form all desired individual license types which are object of face-to-face negotiations between a service provider and a service requestor. Thus, the contract and license management basically falls into two categories: 
        a) high level contracting and     b) low level contracting.        
 
         [0035]     High level contracting deals with the above-mentioned face-to-face negotiations for agreeing on given contract conditions, while low level contracting deals with the runtime implementations of contract attributes as far as they are agreed on by both contracting parties. Personalised licenses between a service provider and a service requestor of web services require a great manual afford and are usually only set up with customers requiring enough licenses to be worth the afford of negotiation.  
         [0036]     One of the disadvantageous limitations of the prior art contract management is that a one-to-one relationship exists between the consumer and the provider of a service offering exists. This represents a major problem to introduce this system to large scale environments, where for instance enterprises want to contract services for a number of consumers, for example a large number of employees using such services. If prior art contract management systems was enriched with existing software licensing know-how, the client could only choose from predefined licenses with a pre-set number of conditions, under which he can use the software or the service. If non of the offered licenses meets his requirements he will have to accept a license, which does not really fit his needs or, alternatively he cannot use the software or the service at all.  
         [0037]     In many business situations the negotiations of different license policies, as it is basically desirable for a client, requires to much interaction in the sales process to be worth the effort for the service supplier. Further, it is also not possible to use well-known and established usage models as they are used in prior art software licensing, as prior art software licensing is coupled to offline processes for situations, in which the usage of a licensed software is done offline and independently from the software provider or the software seller.  
       OBJECTIVES OF THE INVENTION  
       [0038]     It is thus an objective of the present invention to improve prior art methods of performing web services.  
       SUMMARY AND ADVANTAGES OF THE INVENTION  
       [0039]     This objective of the invention is achieved by the features stated in enclosed independent claims. Further advantageous arrangements and embodiments of the invention are set forth in the respective subclaims. Reference should now be made to the appended claims.  
         [0040]     According to the basic aspect of the present invention as defined in claim  1  a basic approach for improving prior art delivering of web services is disclosed, wherein a service consumer may issue a request for a service with using information included in the request, which comprises a kind of user-ID, which enables a service provider to select a valid contract between the service consumer and the service provider. Furthermore, at the service provider site, a customer-specific licensing model is instantiated preferably automatically during runtime by using existing license subcontracts and respective licensing software components in cooperation with a service metering component storing all necessary usage information on usage of services actually provided or provided prior to the current service request, in order to find a respective particular license model, which matches best the actual needs of the client, and which is covered by the contractual scope of the negotiated contract terms and conditions. Thus, different license policies can be followed adaptable to the specific needs of a service requester.  
         [0041]     A preferred way to do that is to offer a plurality of different license types, which is able to cover most of the clients needs, as experience shows. An advantageous collection of different license types comprises the following types: 
        a) a consumptive type, in which only a specific number of requests for the service are allowed optionally, this may be related to a predefined time period, in which that number of requests must be performed;     b) a “concurrent” license type, wherein only a specific number of simultaneous requests of the service are allowed;     c) a time-based license type, wherein service requests are allowed only at specific times. This can either be periodic, for instance Monday to Friday or single type, as for instance January to July 2003;     d) a name-related license type, in which only predefined principles listed in the license policy are allowed to request the service. By that, for example a group of 4 persons can use a service;     e) a “base” type license, wherein no access regulations or usage conditions must be kept, meaning that a service request will be always allowed independently of time, historic consumption and the number of concurrent accesses, which may be preferably granted to a limited number of persons only;     f) a usage condition license type, in which a license policy specifies any predefined usage condition, for example the condition that any reselling of the provided service is not allowed of cause other conditions may exist, which depend clearly from the particular situation and field of use.        
 
         [0048]     The above-mentioned different license types are referred to be “atomic” license types because each individual license type addresses one single and complete separate aspect of usage conditions. Further advantageously said atomic license types can be combined in order to be able to offer a large number of different license models to the customer, a preferred feature, which is not known yet in the world for web services. A combined license type can be obtained by associating an individual, predetermined fraction, for instance percentage of each atomic license type to the combined one, which preferably also may be used for billing purposes.  
         [0049]     Further advantageously the definition of a license or the definition of multiple license types according to the present invention is part of an electronic document specifying the contract underlying to said licenses. By that the advantage results that contract information and license type information is stored close to each other, which increases the ease of use when maintaining those data.  
         [0050]     Further, when the contracting system implementing the different license types according to the present invention further includes a metering software component designed and defined for metering the technical details of the requested services, in particular those details, which may be used to form part of the billing process postponed to the service itself, and when said metering data associated with a current contract ID is read and used for a checking step in order to make a decision if or if not to allow a service provision, then one and the same contract management system comprises all technical software components in one single system, which is needed for efficiently operating the requested services as well as generating the billing procedure associated with the service.  
         [0051]     When further a license verification program module is used having a modular structure for each license type, and if those modules are sequentially operated on when processing an incoming request, then the additional advantage results that the inventional concept is easily to be extended for more license types without being constrained to append much meta-logic around such new module. Further, the inventional concept can be integrated in a contract management system that comprises a profile handler, a contract handler and a metering request handler, wherein such handler components cooperate with respective remotely operated services, i.e. a profile service for checking and validating the personal identity of the requesting person, a contract service for checking the usage of the contract and a metering service for metering any service-relevant entities such as time of usage, amount of data transferred via network, etc., then respective parts of processing can be performed at locations best suited for collecting and processing the respective type of data. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0052]     The present invention is illustrated by way of example and is not limited by the shape of the figures of the drawings in which:  
         [0053]      FIG. 1  is a code section representation showing a prior art SOAP request message contained in a HTTP POST request message;  
         [0054]      FIG. 2  is a code section representation showing the structure of a prior art HTTP request;  
         [0055]      FIG. 3  is a code section representation showing a detail structure of a prior art SOAP message;  
         [0056]      FIG. 4  is a code section representation showing the overall structure of a prior art SOAP message contained in a HTTP POST request message;  
         [0057]      FIG. 5A  is a code section representation showing a section of a prior art exemplary WSDL document used for describing web services;  
         [0058]      FIG. 5B  is the continuation of  FIG. 5A ;  
         [0059]      FIG. 6  is a schematic representation of the relationships between Service Consumer, Service Supplier and Service provider according to a preferred embodiment of the inventional method;  
         [0060]      FIG. 7  is a schematic representation of the main structural elements being used in the scenario given in  FIG. 6 ;  
         [0061]      FIG. 8  is a schematic representation of the relationships between Service Consumer, Service Supplier and Service provider according to further preferred embodiment of the inventional method enriched by the inventional license processing component;  
         [0062]      FIG. 9  is a schematic representation of the main structural elements being used in the scenario given in  FIG. 8 ;  
         [0063]      FIG. 10  is a schematic representation illustrating the control flow in an exemplary embodiment of a license processing software component according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0064]     With reference to  FIG. 6 a  scenario is described in which the service supplier abbreviated further as SS offers the service to the Service Consumer, abbreviated as SC. The Service Provider abbreviated as SP realizes the main part of the contract management infrastructure including the main inventional software components.  
         [0065]     This results in the following interactions, which are implemented according to this embodiment in the respective program module(s) as “steps” of a respective inventional method used by the parties SC, SS, and SP. The steps are enumerated as depicted in the drawing:  
         [0066]     Step  610 : SC initiates a service request in order to invoke a business service, which is provided by SS. SS receives the request.  
         [0067]     Step  620 : SS sends a service request to SP in order to use the contracting system and infrastructure services provided by the SP. In particular, in this embodiment the contracting system services comprise the contracting service, and the infrastructure services are metering service and profiling service.  
         [0068]     Step  630 : SP performs the requested contracting system and infrastructure services, e.g. verifies that a valid contract is available, initiates a meter event and returns the status to SP.  
         [0069]     Step  640 : SS performs the requested service and invokes SP in order to generate adequate meter events.  
         [0070]     Step  650 : SS sends data representing the service result to SC.  
         [0071]     The implementation of step  620  is shown in  FIG. 7  in more detail: The service provider realizes an application server, depicted with a dotted-line frame, which contains a servlet  71 , implementing the runtime environment for service requests, for example a web service runtime environment like Apache Axis.  
         [0072]     The application server also contains multiple handler components denoted with reference signs  72 ,  74 ,  76 . These handlers realize a local implementation of the infrastructure components F-H, which may be realized on remote servers for example as further web services. The handlers  72 ,  74 ,  76  provide local functionality needed to handle the communication with the remote services: 
        A Profile Handler  72  uses external Profile Service  72 A in order to verify the requester&#39;s identity.     A Contract Handler  74  uses external Contract Services  74 A in order to verify the contract state and contract validity.     A Metering Handler  76  generates adequate meter events (start-, end-, adhoc-, cancel events, etc).        
 
         [0076]     The components  71 ,  72 ,  74 ,  76  (servlet and handlers) run in a shared memory environment and communicate through shared data.  
         [0077]     The servlet  71  ensures that the handlers are invoked in the correct order.  
         [0078]     The infrastructure services are described next below:  
         [0079]     The Profile Service  72 A may be basically used as available in above-described prior art.  
         [0080]     The Profile Service provides access to user profile information like name, address, user-ID, etc. Depending on the implementation, this may be expanded to include more information. The Profile Service may be used to save, delete and get profile information.  
         [0081]     For the other services to work correctly, all users of business services must have a profile assigned by the Profile Service. Profiles may be created in advance by using a user interface or by directly editing the XML file that holds profiles. This Profile Service can be replaced by any other identity system like Tivoli Identity Manager.  
         [0082]     The Contract Service  74 A implements a prior art contracting management concept adapted to integrate the inventional licensing component.  
         [0083]     The Metering Service  76 A receives meter events, as explained below, persistently stores the meter events and retrieves meter events upon request. According to this preferred embodiment the Metering Service may be used in conjunction with contract information from the Contract Service  74  to produce a usage report for a particular client using a particular service. It should be noted that the contract service  74 A and the metering service  76 A both are connected for a data exchange with an inventional Licensing Service component  75 A.  
         [0084]     This inventional Licensing Service  75 A cooperates with the Contract Services  74 A and the Metering Service  76 A in order to match best the SC&#39;s service usage with the agreed license situation. More details are described later below.  
         [0085]     The Metering Service  76 A supports three types of operations: 
        recordMeterEvent—saves one meter event     recordMeterEvents—saves multiple meter events     getMeterEvents—retrieves multiple meter events from the Meter Service        
 
         [0089]     Meter events contain the service name and the operation name of the service that was called, timestamps, as well as the ID of the contract used to handle the request. Meter events vary by type, so various ways of charging a service call are possible: 
        Start/end events are used when access to a service is charged by the amount of time used to perform the service;     ad-hoc events are used when access is charged for by the number of times that the service is accessed, or on some other basis besides time.        
 
         [0092]     In addition to the above, two more types of events are available: 
        a) The event “cancelled”, which is used to cancel an event, which has already been sent to the metering service, and     b) the event “unknown”, which is used when the type of event was not supplied by the service requestor.        
 
         [0095]     The interactions between the above described software components are as follows:  
         [0096]     Step  710 : Servlet  71  receives the service request initiated by a Service Supplier, extracts the message context and passes it on to subsequent handler components.  
         [0097]     Step  720 : The message context, a shared data object, passes sequential handler components. The handlers extend/modify the message context and pass it on to the next handler in the chain.  
         [0098]     Step  730 : The Profile Handler  72  initiates a service request to an external Profile Service  72 A comprising a respective database application in order to check the Service Supplier&#39;s identity.  
         [0099]     Step  740 : The Profile Service  72  returns the identity checking result to the SP&#39;s Profile Handler.  
         [0100]     Step  750 : The Contract Handler calls an external Contract Service  74 A in order to identify and validate a corresponding contract: It calls the “getUsageContractsForValidForIdentity” operation and passes the service consumer identity taken from the Profile Service result.  
         [0101]     According to this preferred embodiment the Contract Service  74 A reads the contract ID and then uses a valid contract for this identity. According to a preferred embodiment of the invention the Contract Service  74 A, stores license condition data within respective contract documents in a Contract Service database. Said Contract Service cooperates with said above introduced inventional software component, referred to as License (Verification) component  75 A, which ensures that the service request complies to the license policies predefined in the contract. The details thereof are further explained with reference to  FIG. 10 .  
         [0102]     According to a preferred way of implementing this, an implementation variant A, referred to as step  752 , is as follows:  
         [0103]     The License component  75 A requests actual or historic usage data from the Metering Service  76 A mentioned above. This data is used to evaluate specific types of license policies for instance consumptive, concurrent, etc., as described above.  
         [0104]     According to a useful alternative an implementation variant B is proposed, in which the License component  75 A has the current usage data and uses this data to perform the evaluation. The license evaluation itself is described in more detail with reference to  FIG. 10 .  
         [0105]     Step  760 : The Contract Service  74 A returns the state and validity of license and contract situation to the SP&#39;s Contract Handler. If no valid contract or licensed usage conditions are found, an exception is thrown, and the service request may be rejected.  
         [0106]     Step  770 : The Metering Handler  76  invokes an external Metering Service  76 A in order to generate meter events, which reflect the status of the business service call.  
         [0107]     Step  780 : The Metering Handler returns the updated message context to the Servlet. According to above variant B the Metering Service  76 A notifies the License component  75 A about the usage of the service. The License Component uses this information for the validation of certain license policies, e.g. consumptive or concurrent license usage, see step  750 .  
         [0108]     Step  790 : The Servlet  71  returns the result of the initial service call (request) to the Service Supplier in step  790 .  
         [0109]     In an alternative scenario and with reference to  FIGS. 8 and 9 , the Service Provider offers the service to the Service Consumer. In order to fulfill a service request, the Service Provider requests the service from the Service Supplier. In particular, in:  
         [0110]     Step  810 : SC requests a business service from SP;  
         [0111]     Step  820 : SP uses the contract system and the infrastructure services to verify that a valid contract is available, initiates a start meter event and then requests the service from the SS;  
         [0112]     Step  830 : SS performs the service and returns results to SP; and  
         [0113]     Step  840 : SP generates end meter event and returns business service results to SC.  
         [0114]     The inventional implementation is shown and will be described with reference to  FIG. 9 :  
         [0115]     The service provider realizes an application server as described above with reference to  FIG. 6  and  7 . Thus, mainly the differences are described next below:  
         [0116]     According to this particular embodiment a Service Handler  90 —see right margin of  FIG. 9 —invokes, see step  980 —the external business service, which is provided by a Service Supplier (SS), step  985 .  
         [0117]     The components Servlet  91 , and handlers  72 ,  74 ,  76 , and  90  again run in a shared memory environment and communicate through shared data. The servlet  91  has only respective differences to that one described above in  FIG. 7 , which yield from the particular differences in scenario  2 , and ensures that the handlers are invoked in the correct order.  
         [0118]     A business web service  92  is an external server component provided by the Service Supplier; it is called in a step  910  by the Service Consumer SC, in order to fulfill the requested service call.  
         [0119]     In particular, the interactions between these components are as follows:  
         [0120]     Step  910 : Servlet  91  receives the service request initiated by a Service Consumer (SC), extracts the message context and passes it on to subsequent handler components.  
         [0121]     Steps  720  to  770 —see Scenario  1  above for reference.  
         [0122]     Step  980 : The Service Handler  90  invokes the requested business service  92  and updates the message context with the resulting service responses and in  
         [0123]     Step  985 : returns it to the Service Handler  90 .  
         [0124]     Step  990 : The Service Handler returns the updated message context to the Servlet  91 .  
         [0125]     Step  995 : The Servlet  91  returns the result of the initial call to the Service Consumer.  
         [0126]     The Licensing Component  75 A logic is illustrated in  FIG. 10 .  
         [0127]     The Contract Service  74 A requests, see step  1005 , the validation of a license for a given Service Consumer (principal) and a given service from the License Component  75 A. The SC request indicated as C.request contains the contract, which comprises the license representation.  
         [0128]     According to  FIG. 10  each license policy is evaluated specifically in a predetermined sequence, which is given in here exemplarily only. The control thereof is implemented in a License dispatcher  1010 .  
         [0129]     The calculation  1020  of usage consumption and concurrent usage  1030  is based on metering data, which is requested and input from the Metering Service  76 A via dispatcher  1010 .  
         [0130]     In step  1020  the usage consumption is calculated, ie, questions like: “how often was the service consumed by this principal up to now”, “how often was the service requested by this principal in the current time period”, etc., are posed and answered by a respective Metering data evaluation as part of step  1020 . The usage consumption is then compared to the limit defined in the license, see step  1022 . If the accumulated usage is still lower than delimited in the contract license section describing the consumptive aspect thereof, a further decision  1024  is taken to check, if more license types are available for the contract. In the YES-branch of decision  1024  it is branched back to the license dispatcher  1010 , which enters a similar control flow for the next license type, see calculation  1030 ,  1040 , or  1050 .  
         [0131]     Thus, the license management may be continued with the evaluation of remaining license types, in order to charge the consumer according to the negotiated terms and conditions in the contract. This may also include that a service is charged in a combination of several license types. Or it may mean that the most advantageous “flat rate” (no-restriction/unlimited-use license) aspect is made effective for the service, if this is possible at least for parts of the service to be provided, as for example in a situation, in which  50 % of the service is covered by the Concurrent Usage license type, and the other 50% is covered by time slot license type.  
         [0132]     In the NO-branch of decision  1024  there are no further licenses. Thus, the license generator stores that the current request is supported by the consumptive type license part, and issues a respective positive license validation response in favor to the SC.  
         [0133]     With reference back to decision  1022 , otherwise, in the NO-branch thereof, that is, if the current usage has exceeded the usage allowed by the usage consumption license type, control is transferred to the license generator  1060 , which issues a respective negative license validation response for instance accompanied by a rejection message for the requested service.  
         [0134]     The dispatcher  1010  initiates then a step  1030 , which calculates the concurrent usage (“how many concurrent service requests originated by this principal are currently executed?”). The control flow is similar to that one described above with steps  1022 , and  1024 , but adapted to the number concurrent users.  
         [0135]     In step  1032 , the current usage data is requested from the Metering service  76 A. The license service  75 A issues a respective request to the Metering Service. Depending on the actual embodiment of the inventional method, two different types of requests can be distinguished: The first requests data about the number of times the service was requested before, and the second type requests data about the number of times the service is currently in use. Both requests take the similar parameters, which can be processed by the Metering Service  76 A.  
         [0136]     In a similar way as described above, the steps  1032 ,  1034 , (concurrent usage type)  1040 ,  1042 , and  1044  (Time slot license type), as well as  1050 ,  1052 ,  1054  (Identity-based license type) are performed. If there is a restriction-free license type also agreed upon, this may be used also, if the request is not covered by the precedingly mentioned license types.  
         [0137]     Further, depending on the actual embodiment and application in use, steps  1020 ,  1022 , and  1024  and/or steps  1030 ,  1032 ,  1034  may trigger the activation of the Metering Service  76 A and may use the new Usage Data for the validation. Alternatively, said activation is performed independently, and the usage data is stored, then referenced in ensuing steps  1020 ,  1022 , and  1024  and/or steps  1030 ,  1032 ,  1034 .  
         [0138]     In another variation of an inventional aspect, the metering service  76 A may push the usage data to the License component  75 A. The License component receives these notifications and stores the usage data; it will then not issue a respective request as mentioned above.  
         [0139]     A Response Generator  1070  creates the overall validation: The overall result is “success”, if each license policy is validated successfully.  
         [0140]     As should reveal from the foregoing description, the present invention extends the before-mentioned prior art by establishing the concept of a license: A license specifies access regulations and usage conditions for one or multiple principals for example a user, a group of users, a computer resource or an application identified by a unique name etc.  
         [0141]     A license is expressed according to the invention as a license policy or a combination of multiple license policies. A license policy defines an aspect of an access regulation and/or a usage condition. By combining multiple license policies it is possible to define arbitrary aspects of access regulations and usage conditions. This serves to best match the consumer&#39;s needs.  
         [0142]     A license may refer to a single, entire contract or to one or multiple contract items.  
         [0143]     A representation of a license can either be embedded in a contract representation or can be implemented as a separate document, which is logically linked to a contract. The following listing shows an XML representation of a license, which is embedded in a contract document:  
                                                                                         &lt;UsageContractDoc                name   = MyUsageContract                identitykey   = 313c4dbb-14aa-47c3-84b8-            101718f60116                startdate   = 2002-07-01 00:00:00.000000000           enddate   = 2003-07-01 00:00:00.000000000&gt;        &lt;services&gt;         &lt;service   servicekey   = 0c1f2376-043a-4294-a6ef-0c131cf2243a           ratingkeys   = 3312d44b-3163-4d42-bd5e-366d305e2914       /&gt;         &lt;service   servicekey   = 3ec01bb7-331e-4e89-8256-3e0b0c3b1335           ratingkeys   = 1a2fdeed-026c-47a9-be32-2fb63896303d            /&gt;        &lt;/services&gt;        &lt;license&gt;         &lt;license_policy type = Named&gt;          &lt;identitykey&gt;           4412d44b-3163-4d42-bd5e-366d305e999          &lt;/identitykey&gt;         &lt;/license_policy&gt;         &lt;license_policy type = Consumptive&gt;          &lt;maxRequests&gt;           1000          &lt;/maxRequests&gt;         &lt;/license_policy&gt;         &lt;license_policy type = UsageCondition&gt;          &lt;usageCondition&gt;           ResellingNotAllowed          &lt;/usageCondition&gt;         &lt;/license_policy&gt;         &lt;/license&gt;       &lt;/UsageContractDoc&gt;       End of Listing                  
 
         [0144]     The following examples show, how atomic license policies can be combined according to a preferred aspect of the present invention to form a new license. The atomic policy types used are “basic”, “named”, “concurrent”, “consumptive”, and “timed”; 
        further atomic license policy types are also possible, as a person skilled in the art may appreciate.        
 
         [0146]     In the examples, the licenses are defined inside usage contracts. In this case, the license service  75 A will use the information provided by the contract service  74 A together with the metering data from the metering service  76 A to make a decision at runtime about the validity of the license. This inventional approach allows the easy creation of personalized licenses. Of course it is also possible to modify this inventional approach in several ways, for instance that the license service  75 A acts upon information stored in a license database and only links to a license stored in this database are part of the contract.  
       EXAMPLE 1  
       [0147]    
       
         
               
             
               
               
               
             
               
               
               
             
               
             
           
               
                   
               
               
                   
               
             
             
               
                 &lt;UsageContractDoc 
               
             
          
           
               
                   
                 name 
                 = SampleContract1 
               
             
          
           
               
                   
                 identitykey 
                 = 313c4dbb-14aa-47c3-84b8- 
               
               
                 101718f60116 
               
               
                   
                 startdate 
                 = 2002-07-01 00:00:00.000000000 
               
               
                   
                 enddate 
                 = 2003-07-01 00:00:00.000000000 &gt; 
               
               
                  &lt;services&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 0c1f2376-043a-4294-a6ef- 
               
               
                 0c131cf2243 
               
               
                   
                 ratingkeys 
                 = 3312d44b-3163-4d42-bd5e- 
               
               
                 366d305e291 /&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 3ec01bb7-331e-4e89-8256- 
               
               
                 3e0b0c3b133 
               
               
                   
                 ratingkeys 
                 = 1a2fdeed-026c-47a9-be32- 
               
             
          
           
               
                 2fb63896303 /&gt; 
               
               
                  &lt;/services&gt; 
               
               
                  &lt;license&gt; 
               
               
                   &lt;license_policy type = Named&gt; 
               
               
                     &lt;identity&gt; Donald Duck &lt;/identity&gt; 
               
               
                     &lt;identity&gt; Mickey Mouse &lt;/identity&gt; 
               
               
                    &lt;/license_policy&gt; 
               
               
                     &lt;license_policy type = Consumptive&gt; 
               
               
                     &lt;maxRequestsPerMonth&gt; 1000 &lt;/maxRequestsPerMonth&gt; 
               
               
                   &lt;/license_policy&gt; 
               
               
                    &lt;license_policy type = UsageCondition&gt; 
               
               
                     no reselling allowed 
               
               
                   &lt;/license_policy&gt; 
               
               
                  &lt;/license&gt; 
               
               
                 &lt;/UsageContractDoc&gt; 
               
               
                   
               
             
          
         
       
     
         [0148]     In the example above a license is defined by combining the atomic license policy types “named” mentioning exemplarily Donald Duck and Mickey Mouse, “consumptive”, delimiting the maximum number of requests per month to 1000, and “Usage condition”, mentioning that no reselling of the service is allowed. While the first two license components can be technically enforced, the type usage condition defines a common understanding between the involved parties.  
         [heading-0149]     Named:  
         [0150]     Through the named license policy, two persons (Donald Duck and Mickey Mouse) are allowed to use the services subscribed to by the contract.  
         [heading-0151]     Consumptive:  
         [0152]     The consumptive license policy allows 1000 calls per month to the service subscribed to by the contract.  
         [heading-0153]     Usage condition:  
         [0154]     This license policy forbids the reselling of the services subscribed to by the contract.  
         [0155]     By combining these atomic license policies to form a new license, only the persons listed in the named license policy can use the services subscribed to by the contract for a total of 1000 calls per month.  
       EXAMPLE 2  
       [0156]    
       
         
               
             
               
               
               
             
               
               
               
             
               
             
           
               
                   
               
               
                   
               
             
             
               
                 &lt;UsageContractDoc 
               
             
          
           
               
                   
                 name 
                 = SampleContract2 
               
             
          
           
               
                   
                 identitykey 
                 = 313c4dbb-14aa-47c3-84b8- 
               
               
                 101718f60116 
               
               
                   
                 startdate 
                 = 2002-07-01 00:00:00.000000000 
               
               
                   
                 enddate 
                 = 2003-07-01 00:00:00.000000000 &gt; 
               
               
                  &lt;services&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 0c1f2376-043a-4294-a6ef- 
               
               
                 0c131cf2243 
               
               
                   
                 ratingkeys 
                 = 3312d44b-3163-4d42-bd5e- 
               
               
                 366d305e291 /&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 3ec01bb7-331e-4e89-8256- 
               
               
                 3e0b0c3b133 
               
               
                   
                 ratingkeys 
                 = 1a2fdeed-026c-47a9-be32- 
               
             
          
           
               
                 2fb63896303 /&gt; 
               
               
                  &lt;/services&gt; 
               
               
                  &lt;license&gt; 
               
               
                   &lt;license_policy type = Named&gt; 
               
               
                     &lt;identity&gt; Donald Duck  &lt;/identity&gt; 
               
               
                     &lt;identity&gt; Mickey Mouse &lt;/identity&gt; 
               
               
                     &lt;identity&gt; Superman   &lt;/identity&gt; 
               
               
                    &lt;/license_policy&gt; 
               
               
                    &lt;license_policy type = Concurrent&gt; 
               
               
                     &lt;maxConcurrentRequests&gt; 1 &lt;/maxConcurrentRequests&gt; 
               
               
                   &lt;/license_policy&gt; 
               
               
                  &lt;/license&gt; 
               
               
                 &lt;/UsageContractDoc&gt; 
               
               
                   
               
             
          
         
       
     
         [0157]     In the example above a license is defined by combining the atomic license policy types “named” and “concurrent”. Both license components can be technically enforced.  
         [heading-0158]     Named:  
         [0159]     Through the named license policy, three persons (Donald Duck, Mickey Mouse and Superman) are allowed to use the services subscribed to by the contract.  
         [heading-0160]     Concurrent:  
         [0161]     The concurrent license policy allows only one single call at a time to the service subscribed to by the contract.  
         [0162]     By combining these atomic license policies to form a new license, only one call at a time by any of the persons listed in the named license policy can be done to the services subscribed to by the contract. If the system is currently processing a call to any of these services, no other call (even from another of the listed persons) will succeed.  
       EXAMPLE 3  
       [0163]    
       
         
               
             
               
               
               
             
               
               
               
             
               
             
           
               
                   
               
               
                   
               
             
             
               
                 &lt;UsageContractDoc 
               
             
          
           
               
                   
                 name 
                 = SampleContract3 
               
             
          
           
               
                   
                 identitykey 
                 = 313c4dbb-14aa-47c3-84b8- 
               
               
                 101718f60116 
               
               
                   
                 startdate 
                 = 2002-07-01 00:00:00.000000000 
               
               
                   
                 enddate 
                 = 2003-07-01 00:00:00.000000000 &gt; 
               
               
                  &lt;services&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 0c1f2376-043a-4294-a6ef- 
               
               
                 0c131cf2243 
               
               
                   
                 ratingkeys 
                 = 3312d44b-3163-4d42-bd5e- 
               
               
                 366d305e291 /&gt; 
               
               
                   &lt;service 
                 servicekey 
                 = 3ec01bb7-331e-4e89-8256- 
               
               
                 3e0b0c3b133 
               
               
                   
                 ratingkeys 
                 = 1a2fdeed-026c-47a9-be32- 
               
             
          
           
               
                 2fb63896303 /&gt; 
               
               
                  &lt;/services&gt; 
               
               
                  &lt;license&gt; 
               
               
                   &lt;license_policy type = TimeBased&gt; 
               
               
                    &lt;allowedtime&gt; 
               
               
                     &lt;starttime&gt; 09:00:00 &lt;/starttime&gt; 
               
               
                     &lt;endtime&gt; 12:00:00 &lt;/endtime&gt; 
               
               
                    &lt;/allowedtime&gt; 
               
               
                    &lt;allowedtime&gt; 
               
               
                     &lt;starttime&gt; 18:00:00 &lt;/starttime&gt; 
               
               
                     &lt;endtime&gt; 22:00:00 &lt;/endtime&gt; 
               
               
                    &lt;/allowedtime&gt; 
               
               
                   &lt;/license_policy&gt; 
               
               
                   &lt;license_policy type = Concurrent&gt; 
               
               
                    &lt;maxConcurrentRequests&gt; 2 &lt;/maxConcurrentRequests&gt; 
               
               
                   &lt;/license_policy&gt; 
               
               
                   &lt;license_policy type = Consumptive&gt; 
               
               
                   &lt;maxRequestsPerMonth&gt; 500 &lt;/maxRequestsPerMonth&gt; 
               
               
                   &lt;/license_policy&gt; 
               
               
                 &lt;/license&gt; 
               
               
                 &lt;/UsageContractDoc&gt; 
               
               
                   
               
             
          
         
       
     
         [0164]     In the example above a license is defined by combining the atomic license policy types “time based”, “concurrent” and “consumptive”. All license components can be technically enforced.  
         [heading-0165]     Time based:  
         [0166]     Through the time based license policy, the timeframe during which the services can be requested is specified as 9 to 12 o&#39;clock and 18 to 22 o&#39;clock.  
         [heading-0167]     Concurrent:  
         [0168]     The concurrent license policy allows only two calls at a time to the service subscribed to by the contract.  
         [heading-0169]     Consumptive:  
         [0170]     The consumptive license policy allows 1000 calls to the service subscribed to by the contract.  
         [0171]     By combining these atomic license policies the following new license is created: Calls to any of the services subscribed to by the contract can only be made in the timeframes specified under the policy type “time based”. But even within the times listed there, only two calls can be made simultaneously, while no more than 500 calls per month are possible at all.  
         [0172]     The present invention can be realized in hardware, software, or a combination of hardware and software. A tool according to the present invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software could be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.  
         [0173]     The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which—when loaded in a computer system—is able to carry out these methods.  
         [0174]     Computer program means or computer program in the present context mean any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: 
        a) conversion to another language, code or notation;     b) reproduction in a different material form.