术语“刷新"是什么意思?和“查询"ADF 中的迭代器绑定平均值的平均值? [英] What does the terms "refresh" and "query" mean for an Iterator binding mean in ADF?

问题描述

我对 ADF 中使用的一些术语有一些困惑，主要是关于迭代器绑定.

I am having some confusion about some terminology used in ADF mainly in regards to the Iterator Binding.

1. ADF 中 Iterator Binding 上的 Refresh 标志的用途是什么?
2. 建议何时(在生命周期的哪个阶段)进行刷新，为什么?
3. 刷新迭代器和查询迭代器在 ADF 中的区别是什么?

1. What is the purpose of the Refresh flag on an Iterator Binding in ADF?
2. When(In which phase of the Lifecycle) is it recommended to do the refresh and why?
3. What is the difference between refreshing an iterator and querying an iterator in ADF-speak?

推荐答案

1. Refresh 表示将绑定层迭代器重新绑定到 VO 行集迭代器.当接收到页面请求时重建页面并重新创建绑定层时会发生这种情况.查询会导致 VO 重新查询数据源并重建行集迭代器.除非尚未创建 VO 行集，否则刷新不会导致(重新)查询.
2. 可以根据需要在生命周期的不同点进行刷新.正常设置延迟"通常没问题(请参阅下面的文档).
3. 刷新指示何时重新绑定迭代器.

来自文档:ADF 文档在运行时，可执行绑定根据其 Refresh 属性的值进行刷新.刷新迭代器绑定会将其与其底层 RowSetIterator 对象重新连接.刷新调用操作绑定会调用该操作.在刷新任何绑定之前，ADF 运行时会评估在可执行文件中指定的任何 Refresh 和 RefreshCondition 属性.Refresh 属性指定应调用可执行文件的 ADF 生命周期阶段.RefreshCondition 属性指定应调用可执行文件的条件.您可以使用布尔 EL 表达式指定 RefreshCondition 值.如果将 RefreshCondition 属性留空，则它的计算结果为 true.默认情况下，刷新值设置为延迟.这意味着除非访问其值(例如通过 JSF 页面上的 EL 表达式)，否则不会执行绑定.一旦调用，除非绑定的任何参数值已更改，或者绑定本身已更改，否则它将不会重新执行.在 Fusion Web 应用程序中使用 ADF 模型 12-29创建 ADF 数据绑定 EL 表达式有关如何刷新绑定以及如何设置 Refresh 和 RefreshCondition 属性的更多信息，请参阅第 21.2 节JSF 和 ADF 页面生命周期".

From the Docs: ADF Docs At runtime, executable bindings are refreshed based on the value of their Refresh attribute. Refreshing an iterator binding reconnects it with its underlying RowSetIterator object. Refreshing an invoke action binding invokes the action. Before refreshing any bindings, the ADF runtime evaluates any Refresh and RefreshCondition attributes specified in the executables. The Refresh attribute specifies the ADF lifecycle phase within which the executable should be invoked. The RefreshCondition attribute specifies the conditions under which the executable should be invoked. You can specify the RefreshCondition value using a boolean EL expression. If you leave the RefreshCondition attribute blank, it evaluates to true. By default, the Refresh value is set to deferred. This means the binding will not be executed unless its value is accessed (for example by an EL expression on a JSF page). Once called, it will not reexecute unless any parameter values for the binding have changed, or if the binding itself has changed. Using ADF Model in a Fusion Web Application 12-29 Creating ADF Data Binding EL Expressions For more information about how bindings are refreshed and how to set the Refresh and RefreshCondition attributes, see Section 21.2, "The JSF and ADF Page Lifecycles."

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