毕业设计(论文)外文资料翻译学生姓名： 学 号： 所在学院： 电子与信息工程学院 专 业： 计算机科学与技术 指导教师： 2011年 12月 25 日English Data Original TextTranslates the foreign materials: Author: Jayakrishnan Ramdas(jkramdasinfosys.com), Senior Technology Architect, Infosys LTD J. Srinivas(jsrinivasinfosys.com), Principal Architect, Infosys LTD Book title (or paper topic): Extend Java EE containers with cloud characteristics Publishing house (or publication name): http:/www.ibm.com/developerworks/cloud/library Publication time (or registration number): august 2011Extend Java EE containers with cloud characteristicsStrategies and patterns to extend JEE containers/apps with parallelism, elasticity, multi-tenancy, and securityThe Java Enterprise Edition (JEE) architecture is based on components with features that effectively manage application transactions and statefulness, multi-threading, and resource pooling. A JEE application is easier to write even with complex requirements since the business logic is organized in reusable components and the server provides the underlying services in the form of a container for each component type.We thought it would be a novel idea to add even more power to the concept of container services in JEE by adding support for some of the powerful ideas of cloud computing namely parallelism, elasticity, multi-tenancy, and security. This article describes the strategies and patterns to extend JEE containers and applications with cloud computing characteristics. It includes: An outline of each cloud characteristic we integrated. A layout of the existing characteristics of JEE applications. A description of our approach to extend the JEE container to the cloud. A design strategy for this type of migration, one that includes the concepts of parallelism, synchronization, storage, elasticity, multi-tenancy, and security.Cloud characteristicsFigure 1 explains what cloud is and the different cloud deployment models.Figure 1. A birds eye view of cloud service models and their componentsAt the bottom of the cloud stack is the Infrastructure as a Service (IaaS) level. Here the infrastructure has moved to cloud and the cloud now facilitates the deployment of software including business applications. However the IaaS does not have an application-development environment or any testing services. As the figure shows, the top level of abstraction is elasticity, automated deployment, and utility computing.The Platform as a Service (PaaS) level provides an environment for application software to be created, deployed, and maintained. The PaaS provider has to give the basic life cycle services like build, deploy, testing and building block services like state management, transaction, and security, as well as resource management services through the runtime.The Software as a Service (SaaS) level provides an environment for the end-user to access an application and use it.The basic cloud characteristics that an application needs to support are elasticity and multi-tenancy. Other characteristics, like provisioning and automation, are supported through the deployment features of the application server and do not have much of an impact on the code. Parallelism, distributed storage needs, and security enhancements act as supporting characteristics that need to be addressed to achieve elasticity and multi-tenancy.Lets look at each in more detail.ElasticityElasticity is the ability to scale up and down the infrastructure based on need. During peak load times, more instances are added to the cluster and when the load comes down, the number of instances comes down. This should be done dynamically. This function is enabled by features of the application server to support dynamic clustering techniques.Elasticity is not just an application server solution; the application itself should be able to support elasticity. This means the application needs to be designed to handle the resources that it uses to support concurrency. By designing or customizing an application to support elasticity, you imply that youve also implemented parallelism, statelessness, and transaction support in your application.The design strategy section describes how to implement elasticity that has all the resources support statelessness in execution and parallelism.Multi-tenancyMulti-tenancy means your application has the ability for a single application instance to cater to multiple customers; this means that if five customers are using a content management service, then all five customers can use the same application instance with adequate segregation of data and execution parameters. To support multi-tenancy, your application needs to engage distributed storage, parallelism, security, and loose coupling.There are two approaches to support multi-tenancy: A single physical storage