阅读说明：本技术 流量控制方法以及设备 (Flow control method and device ) 是由 聂志红 王孟杰 吴义良 于 2021-08-05 设计创作，主要内容包括：本申请实施例提供了一种流量控制方法以及设备,该方案在获取待处理消息后,会先在缓存中查询关于所述待处理消息的流量控制结果,若未查询到所述关于所述待处理消息的流量控制结果,则表示未对待处理消息的同源消息进行过流量控制,可以进一步判断所述待处理消息的类型是否为创建类型,不同的判断结果,可以基于待处理消息进行不同的处理,由此实现对流量进行控制的处理逻辑,从而在确保灰度测试的流量分配的同时,避免同源流量被分配至不同的系统中导致新系统无法处理部分流量的问题。(The embodiment of the application provides a flow control method and device, after a message to be processed is obtained, a flow control result related to the message to be processed is inquired in a cache, if the flow control result related to the message to be processed is not inquired, the flow control result indicates that the over-flow control is carried out on a homologous message of the message not to be processed, whether the type of the message to be processed is a creation type or not can be further judged, different judgment results can be carried out on the basis of the message to be processed, and therefore the flow control processing logic is achieved, and the problem that a new system cannot process part of flow due to the fact that homologous flow is distributed to different systems while the flow distribution of a gray level test is guaranteed.)

1. A method of flow control, the method comprising:

acquiring a message to be processed, and inquiring a flow control result related to the message to be processed in a cache;

if the flow control result related to the message to be processed is not inquired, judging whether the type of the message to be processed is a creation type;

if the type of the message to be processed is the creation type, distributing a target system of the message to be processed according to a preset filtering rule, writing a distribution result serving as a flow control result of the message to be processed into the cache, and sending the message to be processed to the target system;

if the type of the message to be processed is a non-creation type, determining a homologous system corresponding to the message to be processed as a target system, and sending the message to be processed to the target system, wherein the homologous system is a system to which a homologous message corresponding to the message to be processed is sent, and the homologous message is a message with the same source as the message to be processed;

and if the flow control result related to the message to be processed is inquired, determining a target system of the message to be processed from the flow control result, and sending the message to be processed to the target system.

2. The method of claim 1, wherein the target system comprises a new system and an old system.

3. The method of claim 2, wherein allocating the target system of the pending message according to the preset filtering rule comprises:

acquiring the associated information of the message to be processed, and matching the associated information with a preset filtering rule;

if the filtering rule is hit, determining a new system as a target system of the message to be processed;

and if the filtering rule is not hit, determining an old system as a target system of the message to be processed.

4. The method of claim 1, wherein writing an allocation result to the cache as a flow control result of the pending message comprises:

and determining the source identifier of the message to be processed, and writing the message to be processed and the target system distributed by the message to be processed into the cache so as to establish the mapping relation between the source identifier of the message to be processed and the target system.

5. The method according to any one of claims 1 to 4, wherein the message to be processed is an order message, the order message of creation type comprises an order creation message for creating an order in the target system, and the order message of non-creation type comprises a message other than an order for performing a secondary operation on the created order in the target system.

6. The method of claim 5, wherein the filtering rules include at least any one of:

the modulus taking result of the order mark of the order message meets a first preset condition;

the number of the messages distributed to the target system meets a second preset condition;

the user identification of the order message meets a third preset condition.

7. The method of claim 5, wherein the cache is packaged separately in a toolkit.

8. The method of claim 1, wherein obtaining the pending message comprises:

and acquiring the to-be-processed message sent by the message queue based mechanism.

9. A flow control apparatus, wherein the apparatus comprises a memory for storing computer program instructions and a processor for executing the computer program instructions, wherein the computer program instructions, when executed by the processor, trigger the apparatus to perform the method of any of claims 1 to 8.

10. A computer readable medium having stored thereon computer program instructions executable by a processor to implement the method of any one of claims 1 to 8.

Technical Field

The present application relates to the field of information technology, and in particular, to a flow control method and apparatus.

Background

With the expansion and increase of service systems, a need for modifying the service systems arises, and a part of traffic generally needs to be filtered out in the modification process to perform a gray level test on the modified service systems, so as to verify whether a new system has a problem. At present, the flow control mode during the gray scale test is single, and the flow is generally controlled simply according to the filtering rule, namely the flow which meets the filtering rule is directly forwarded to a new system for processing, and the flow which does not meet the filtering rule is still forwarded to an old version of system for processing.

However, this approach is not applicable to all internet traffic scenarios. As in the order transaction system, the entire fulfillment of the order is procedural, including placing orders, paying, sorting, shipping, receiving, order confirmation, etc. The overall process cycle is long, thus in the case of two systems, it is necessary to ensure that the order goes through one system. If the order is created in the new system, subsequent messages relating to the order all need to be processed by the new system, whereas if the order is created in the old system, subsequent messages relating to the order all need to be processed by the old system. However, the current flow control method based on the filtering rule is equivalent to that only one simple classification is performed at the entrance of the new and old systems, so that the subsequent order message of the order created in the old system is likely to be transferred to the new system, and the transferred subsequent order message cannot be processed in the new system due to the lack of necessary information about the order.

In summary, the current flow control method for gray scale testing is not suitable for the service scenarios in which the previous and subsequent related flows exist in the same source, which may cause that the new system cannot process part of the flows.

Disclosure of Invention

An object of the present application is to provide a flow control method and device, so as to solve the technical problem that the existing flow control method is not suitable for a service scenario in which context is associated with a homologous flow.

In order to achieve the above object, an embodiment of the present application provides a flow control method, where the method includes:

acquiring a message to be processed, and inquiring a flow control result related to the message to be processed in a cache;

if the flow control result related to the message to be processed is not inquired, judging whether the type of the message to be processed is a creation type;

if the type of the message to be processed is the creation type, distributing a target system of the message to be processed according to a preset filtering rule, writing a distribution result serving as a flow control result of the message to be processed into the cache, and sending the message to be processed to the target system;

if the type of the message to be processed is a non-creation type, determining a homologous system corresponding to the message to be processed as a target system, and sending the message to be processed to the target system, wherein the homologous system is a system to which a homologous message corresponding to the message to be processed is sent, and the homologous message is a message with the same source as the message to be processed;

and if the flow control result related to the message to be processed is inquired, determining a target system of the message to be processed from the flow control result, and sending the message to be processed to the target system.

Further, the target system includes a new system and an old system.

Further, the target system for distributing the messages to be processed according to the preset filtering rule comprises:

acquiring the associated information of the message to be processed, and matching the associated information with a preset filtering rule;

if the filtering rule is hit, determining a new system as a target system of the message to be processed;

and if the filtering rule is not hit, determining an old system as a target system of the message to be processed.

Further, writing the allocation result into the cache as the flow control result of the message to be processed, including:

and determining the source identifier of the message to be processed, and writing the message to be processed and the target system distributed by the message to be processed into the cache so as to establish the mapping relation between the source identifier of the message to be processed and the target system.

Further, the message to be processed is an order message, the order message of the creation type includes an order creation message for creating an order in the target system, and the order message of the non-creation type includes a message for excluding orders for performing secondary operations on the created order in the target system.

Further, the filtering rules include at least any one of:

the modulus taking result of the order mark of the order message meets a first preset condition;

the number of the messages distributed to the target system meets a second preset condition;

the user identification of the order message meets a third preset condition.

Further, the cache is packaged in a tool kit separately.

Further, acquiring the message to be processed includes:

and acquiring the to-be-processed message sent by the message queue based mechanism.

Some embodiments of the present application also provide a flow control device, wherein the device comprises a memory for storing computer program instructions and a processor for executing the computer program instructions, wherein the computer program instructions, when executed by the processor, trigger the device to perform the aforementioned flow control method.

Further embodiments of the present application also provide a computer readable medium having stored thereon computer program instructions executable by a processor to implement the flow control method.

Compared with the prior art, the flow control scheme provided by the embodiment of the application queries the flow control result related to the message to be processed in the cache after the message to be processed is acquired, and if the flow control result related to the message to be processed is not queried, it indicates that the flow control is performed on the homologous message of the message not to be processed, so that whether the type of the message to be processed is the creation type can be further judged; if the type of the message to be processed is the creation type, it indicates that the message to be processed is the first message in the previous and next related homologous messages, and the message to be processed is allocated to a new system without causing the failure of processing. If the type of the message to be processed is a non-creation type, it indicates that the message to be processed is not the first message in the homologous messages related in the front and back, and a homologous system corresponding to the message to be processed needs to be determined as a target system and sent to the same system for processing; if the flow control result related to the message to be processed is inquired in the cache, the flow control result indicates that the flow control is already performed on the homologous message of the message to be processed, the target system of the message to be processed is determined from the flow control result, and the target system is sent to the same system for processing. Therefore, by the control logic in the scheme, the problem that a new system cannot process partial flow due to the fact that the same source flow is distributed to different systems can be avoided while ensuring the flow distribution of the gray scale test.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

fig. 1 is a processing flow chart of a flow control method according to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of applying the solution provided by the embodiment of the present application to an order business scenario;

FIG. 3 is a flow chart of a system using the architecture shown in FIG. 2 for implementing flow control of order messages in an embodiment of the present application;

the same or similar reference numbers in the drawings identify the same or similar elements.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In a typical configuration of the present application, the terminal, the devices serving the network each include one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media, which include both non-transitory and non-transitory, removable and non-removable media, may implement the information storage by any method or technology. The information may be computer program instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

The flow control method provided by the embodiment of the application is applied to flow control between a new system and an old system during gray scale testing. In some service scenarios, multiple messages that need to be processed by the service system may have the same source, for example, in the e-commerce field, a new order service system and an old order service system during a gray scale test may receive processing messages related to different stages of a certain order, such as an order creation message, an order cancellation message, an order payment message, an order delivery message, and the like. For example, in the field of data storage, new and old database systems performing a gray scale test may also receive processing messages related to different stages of a certain data, such as a message for creating a data record, a message for modifying a data record, a message for deleting a data record, and the like, and these messages have a common point that all are directed to the same data record, and may also have the same source and belong to the same source message.

Because the new system and the old system are independent from each other, the message processing process belongs to an isolation environment, and if the homologous messages in different processing stages are processed in the new system and the old system respectively, the system can cause processing failure due to lack of preposed data when processing the homologous messages in the later processing stage. For example, if a creation message of an order is distributed to an old system for processing according to a filtering rule, or the creation of the order is already completed in the old system before the order is subjected to a gray scale test, and when an order payment message of the order is generated, the order payment message is distributed to a new system for processing, the new system may fail to process due to lack of relevant data related to the creation of the order.

The information to be processed by the scheme in the embodiment of the application is the similar homologous information, and reasonable control logic is set at the inlet of the new system and the old system for the flow, so that the flow distribution of the gray scale test can be ensured, and the problem that the new system cannot process part of the flow because the homologous flow is distributed to different systems is avoided.

In an actual scenario, the execution subject of the method may be a user device, a network device, or a device formed by integrating the user device and the network device through a network, or may also be an application program running on the device. The user equipment comprises but is not limited to various terminal equipment such as a computer, a mobile phone and a tablet computer; including but not limited to implementations such as a network host, a single network server, multiple sets of network servers, or a cloud-computing-based collection of computers. Here, the Cloud is made up of a large number of hosts or web servers based on Cloud Computing (Cloud Computing), which is a type of distributed Computing, one virtual computer consisting of a collection of loosely coupled computers. In addition, the execution subject of the method may also be a program running in the above-mentioned apparatus, and may be implemented as, for example, a flow control component, a module, or the like. Fig. 1 shows a processing flow of a flow control method provided in an embodiment of the present application, where the method is applied to flow control between a new system and an old system during a gray scale test, and includes at least the following steps:

step S101, obtaining the message to be processed, and inquiring the flow control result of the message to be processed in the cache. The message to be processed refers to a message to be processed in a primary flow control process, and taking an order service scenario as an example, the message to be processed may be a message of order creation, order payment, order modification, order shipment, order completion, and the like, and corresponds to each stage of order processing. Before entering the order business system, the messages can be subjected to flow control at the entrance, so that the distribution of the messages to be processed is realized. In a practical scenario, the pending messages may interact based on a mechanism of a message queue.

The cache stores the flow control result about the to-be-processed message, where the flow control result about the to-be-processed message may be an allocation result of a message that is a same source of the to-be-processed message, for example, if the to-be-processed message acquired this time is a payment message about order a1, the message that is the same source may be a creation message of order a1, and the cache may store the flow control result about the creation message of order a1, that is, an allocation result about the creation message of order a 1. If the distribution result of the creation message of the order a1 is stored in the cache, the cache can be hit, and the flow control result of the message to be processed is queried in the cache, otherwise, the query cannot be completed, and for different query results, subsequent processing can be performed in different manners.

Step S102, if the flow control result related to the message to be processed is not inquired, judging whether the type of the message to be processed is a creation type.

When the flow control result related to the message to be processed is not queried, it indicates that the current message to be processed does not have a flow control performed on the same source message by the scheme of the embodiment, that is, the current message to be processed is a first message of all the same source messages, which performs flow control by the scheme. The possible reasons include at least two: 1. the type of the message to be processed is a creation type, namely, the creation message of the first stage in the homologous message; 2. the message to be processed is not a creation type, but before the homologous message of the previous stage of the message to be processed reaches, a new system for performing gray scale test is not accessed, and all the homologous messages of the previous stage are processed by the old system.

Therefore, the step needs to distinguish the two cases, and therefore, it needs to further determine whether the type of the message to be processed is the creation type. Taking the order service scenario as an example, the to-be-processed message is an order message, the creation type order message includes an order creation message for creating an order in the target system, and the non-creation type order message includes a message other than an order for performing a secondary operation on the created order in the target system. When the flow control result of the payment message about order a1 is not queried in the cache, it needs to be further determined whether the type of the payment message of order a1 is non-creation type, obviously, the type of the payment message of order a1 is payment type, and belongs to non-creation type, not creation type. The subsequent processing in step S103 and step S104 may be performed for different determination results, respectively.

Step S103, if the type of the message to be processed is the creation type, distributing the target system of the message to be processed according to a preset filtering rule, writing a distribution result into the cache as a flow control result of the message to be processed, and sending the message to be processed to the target system.

When the target system of the message to be processed is distributed according to a preset filtering rule, the associated information of the message to be processed can be obtained, the associated information is matched with the preset filtering rule, if the filtering rule is hit, a new system is determined as the target system of the message to be processed, and if the filtering rule is not hit, an old system is determined as the target system of the message to be processed. The pending message may then be sent to the determined target system, and processed by the target system, for example, when the determined target system is a new system, the pending message may be sent to the new system for processing, and when the determined target system is an old system, the pending message may be sent to the old system for processing.

The associated information of the to-be-processed message may be any information that is associated with the to-be-processed message and can be used for rule matching, and may be information carried by the to-be-processed message itself, such as an order identifier such as an order number, a user identifier of the order, or information related to the current state of the flow control process in which the to-be-processed message participates, such as the number of messages that have been currently distributed to a new system or a system by the scheme of this embodiment. Thus, the preset filtering rule in the embodiment of the present application may include at least any one of the following:

the modulo result of the order identifier of the order message meets the first preset condition, for example, when the order identifier is the order number in the digital form, the order number may be modulo 2, and then the modulo result is 1, which is set as the first preset condition, so that the order of the order number 202107272134771 will hit the filtering rule, whereas the order of the order number 202107272135668 will miss the filtering rule because the modulo result is 0.

The number of messages already allocated to the target system meets the second preset condition, and in this embodiment, the target system for allocating traffic includes a new system and an old system, and whether the second preset condition is met may be determined based on the number of messages already allocated to a certain target system (e.g., the new system). If the second preset condition set in this embodiment is less than or equal to 1000, when the number of messages already distributed to the target system is less than 1000, the current message to be processed hits the filtering rule.

The user identification of the order message meets a third preset condition, the user identification can be a user name, a user number and the like, and a part of orders generated by the user can be appointed to enter a new system through the filtering rule, for example, the last digit of the user number is an appointed number, the user name contains a certain appointed character and the like.

It will be understood by those skilled in the art that the specific contents of the filtering rules are merely exemplary, and other forms based on similar principles now or later developed should be included in the scope of the present application if applicable to the present application and are incorporated herein by reference.

After the target system of the message to be processed is allocated according to the preset filtering rule, the allocation result may be written into the cache as the flow control result of the message to be processed, so as to update the content in the cache for the query processing in the foregoing step S101. In order to make the query more efficient and accurate, in the scheme of the embodiment of the present application, when writing the allocation result into the cache as the flow control result of the to-be-processed message, the source identifier of the to-be-processed message may be determined first, and the to-be-processed message and the allocated target system thereof are written into the cache, so as to establish a mapping relationship between the source identifier of the to-be-processed message and the target system. For example, for an order business scenario, its source identifier may be set as an order identifier, and thus messages with the same order identifier may be considered to be homologous messages, such as a create message, a payment message, an outgoing message, etc. of order a 2.

And writing the message to be processed and the target system distributed by the message to be processed into the cache to establish a mapping relation between the source identifier of the message to be processed and the target system. For example, if the current pending message is a creation message of the order a2, and the target system of the pending message is assigned as a new system according to the preset filtering rule, the order number 202107272134771 of the order a2 may be obtained, and then the creation message of the order a2 and the assigned target system may be written into the cache, so as to establish a mapping relationship between the source identifier 202107272134771 of the order a2 and the new system. Therefore, in the foregoing step S101, all subsequent homologous messages related to the order with the order number of 202107272134771 can be queried in the cache for the corresponding flow control result.

In an actual scenario, the cache may be implemented by any cache tool existing in the market, such as a Remote Dictionary service (Redis), and the cache may be separately encapsulated in a toolkit, and does not need to be configured by a caller of the scheme, so that implementation of the scheme may be more convenient.

And step S104, if the type of the message to be processed is a non-creation type, determining a homologous system corresponding to the message to be processed as a target system, and sending the message to be processed to the target system.

The source system is a system to which a source message corresponding to the message to be processed has been sent, and the source message is the same as the source of the message to be processed. If a message to be processed does not inquire a corresponding flow control result in the cache and the type is a non-creation type, the message to be processed needs to be sent to a system for processing the homologous message of the message to be processed, so that the target system is ensured that data cannot be lost when the message is processed, and the situation that the message cannot be processed is avoided. For example, for the aforementioned payment message of order a1, if its source message (creation message of order a 1) is processed by the old system, that is, the source system is the old system, the old system may determine as the target system, and send the pending message to the old system for processing by the old system.

Step S105, if the flow control result related to the message to be processed is inquired, determining a target system of the message to be processed from the flow control result, and sending the message to be processed to the target system.

When the flow control result about the message to be processed is inquired, the distribution result of the homologous message which has been subjected to flow control before can be determined, and therefore the target system of the message to be processed can be determined according to the distribution result. For example, taking the payment message of order a1 as an example, if the cache stores the allocation result of "order a1 with order number 202107272199832 has been allocated to the new system by the flow control", the allocation result is the flow control result of the payment message related to order a 1. At this point, the new system is also identified as the target system for the payment message of order a1 and sent to the new system for processing. On the contrary, if the information stored in the cache points to the system which is the target system of the payment message of the order a1 and the old system is used for processing, the payment message of the order a1 is sent to the old system.

Therefore, by the control logic, the problem that a new system cannot process part of traffic due to the fact that the same source traffic is distributed to different systems can be avoided while the traffic distribution of the gray scale test is ensured, and the normal operation of a business system during the gray scale test is ensured.

Fig. 2 shows a framework when the solution provided by the embodiment of the present application is applied to an order business scenario, where an order Message is generated based on user behaviors involved in a transaction, for example, an order creation Message corresponds to an order placing behavior of a buyer user, an order payment Message corresponds to a payment behavior of the buyer user, an order cancellation Message corresponds to an order canceling behavior of the buyer user, an order shipment Message corresponds to a shipment behavior of a seller user, and the like, and the order Message is transmitted by using a mechanism of MQ (Message Queue).

The flow control scheme in the embodiment of the application may be implemented as a flow control component, where the flow control component includes a rule manager, a flow controller, and a cache manager, where the rule manager is configured to manage a preset filtering rule and implement functions such as configuration and judgment of the filtering rule, the flow controller is configured to control a flow direction of an order message and implement flow distribution, and the cache manager is configured to manage contents stored in the process and implement functions such as cache query. The target system for processing the order message comprises a new system and an old system, and both the new system and the old system can comprise various subsystems required for realizing order business processing, such as an order receiving system, an order center, a warehouse-out system, a payment system, an order production system and the like.

When the system of the framework realizes the flow control of the order message, the flow is shown in fig. 3, and at least the following steps are included:

step S301, the flow of the order message enters the flow control component.

In step S302, the flow control component queries whether a flow control result regarding the order message already exists in the cache.

Step S303, the flow control component judges whether the cache is hit, if so, the flow control component executes step S307 according to the information stored in the cache, and the new system or the old system processes the flow control component; if not, step S304 is executed.

In step S304, the flow control component determines whether the order message is a create type. If the type is the creation type, the step S305 is executed continuously; if it is not the creation type, step S307 is executed and the old system performs the processing.

Step S305, based on the associated information of the order message, the rule manager matches according to the filtering rule, determines whether the order message is distributed to the new system or the old system, executes the corresponding step, and processes the order message by the new system or the old system.

Step S306, writing the allocation result into the cache as the flow control result of the order message.

Step S307, controlling the order message to enter the new system or the old system, processing the order message by the new system or the old system, and returning the processing result.

When the method is applied to an order business scene, the order message is firstly determined to be a system needing to enter through the flow control component before entering the business system, and if the order message is the message of the same order, even if the filtering rule is changed, the subsequent message processing of the order is not influenced. In addition, the processing mode can also be applied to other scenes except the order business, such as any environment isolation scene of homologous data.

Embodiments of the present application further provide a flow control device, which includes a memory for storing computer program instructions and a processor for executing the computer program instructions, where the computer program instructions, when executed by the processor, trigger the device to implement the methods and/or technical solutions of the foregoing embodiments of the present application.

In particular, the methods and/or embodiments in the embodiments of the present application may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method illustrated in the flow chart. The computer program, when executed by a processing unit, performs the above-described functions defined in the method of the present application.

It should be noted that the computer readable medium described herein can be a computer readable signal medium or a computer readable storage medium or any combination of the two. A computer readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present application, a computer readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

In this application, however, a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, fiber optic cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).

The flowchart or block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

As another aspect, the present application also provides a computer-readable medium, which may be contained in the apparatus described in the above embodiments; or may be separate and not incorporated into the device. The computer-readable medium carries one or more computer program instructions that are executable by a processor to implement the methods and/or aspects of the embodiments of the present application as described above.

It should be noted that the present application may be implemented in software and/or a combination of software and hardware, for example, implemented using Application Specific Integrated Circuits (ASICs), general purpose computers or any other similar hardware devices. In some embodiments, the software programs of the present application may be executed by a processor to implement the above steps or functions. Likewise, the software programs (including associated data structures) of the present application may be stored in a computer readable recording medium, such as RAM memory, magnetic or optical drive or diskette and the like. Additionally, some of the steps or functions of the present application may be implemented in hardware, for example, as circuitry that cooperates with the processor to perform various steps or functions.

It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or means recited in the apparatus claims may also be implemented by one unit or means in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.