Topic (Java EE 5)

Topic 对象封装特定于提供者的主题名称。客户端通过这种方式将主题的身份指定给 JMS API 方法。对于那些将 Destination 用作形参的方法，Topic 对象可用作实参。例如，通过调用以下两个方法，可以使用 Topic 创建 MessageConsumer 和 MessageProducer：

Session.CreateConsumer(Destination destination)
Session.CreateProducer(Destination destination)

许多发布/订阅 (pub/sub) 提供者将主题分组为层次结构，并提供各种选项来订阅层次结构的各部分。JMS API 对 Topic 对象所代表的内容不加限制。它可能是主题层次结构中的叶节点，也可能是层次结构的较大部分。

主题的组织和对主题的订阅粒度是 pub/sub 应用程序架构的重要部分。JMS API 没有为应如何执行此操作指定策略。如果应用程序使用特定于提供者的主题分组机制，它应对此进行记录。如果使用不同的提供者安装该应用程序，则管理员负责构造等效的主题架构，并创建等效的 Topic 对象。

version

1.1 - February 2, 2002

英文文档：

A Topic object encapsulates a provider-specific topic name. It is the way a client specifies the identity of a topic to JMS API methods. For those methods that use a Destination as a parameter, a Topic object may used as an argument . For example, a Topic can be used to create a MessageConsumer and a MessageProducer by calling:

Session.CreateConsumer(Destination destination)
Session.CreateProducer(Destination destination)

Many publish/subscribe (pub/sub) providers group topics into hierarchies and provide various options for subscribing to parts of the hierarchy. The JMS API places no restriction on what a Topic object represents. It may be a leaf in a topic hierarchy, or it may be a larger part of the hierarchy.

The organization of topics and the granularity of subscriptions to them is an important part of a pub/sub application's architecture. The JMS API does not specify a policy for how this should be done. If an application takes advantage of a provider-specific topic-grouping mechanism, it should document this. If the application is installed using a different provider, it is the job of the administrator to construct an equivalent topic architecture and create equivalent Topic objects.

Version:: 1.1 - February 2, 2002
Author:: Mark Hapner, Rich Burridge, Kate Stout
See Also:: Session.createConsumer(Destination), Session.createProducer(Destination), TopicSession.createTopic(String)

Method Summary
`String`	`getTopicName()` Gets the name of this topic.
`String`	`toString()` Returns a string representation of this object.

Method Detail

public String getTopicName() throws JMSException
获取此主题的名称。
依赖于该名称的客户端是不可移植的。

return 主题名称

Throws JMSException: 如果 `Topic` 的 JMS 提供者实现由于某个内部错误无法返回主题名称。

英文文档：
getTopicName

String getTopicName()
                    throws JMSException

Gets the name of this topic.

Clients that depend upon the name are not portable.

Returns:: the topic name
Throws:: JMSException - if the JMS provider implementation of Topic fails to return the topic name due to some internal error.