dbo:abstract
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- In computer programming, suppose we have a data item A whose value depends on data item B, i.e., the value of A must be changed after the value of B changes and before the value of A becomes necessary. Active updating is updating A immediately after B changes, while passive updating or lazy updating (lazy evaluation) is updating A immediately before its value is fetched. And example of this distinction is, e.g., in the implementation of GUI applications: the list of submenu items may depend on the state of the application; this list may be updated either as soon as the state of the application changes ("active") or only when the menu is invoked ("passive"). Another example is update a visual display as soon as the underlying data change as opposed to clicking the "redraw" button. In this situation active update may create a problem to deal with: an abrupt change of some part of the display may coincide in time with the saccadic movement of the eye, and the change may go unnoticed by a human observer. (en)
- 主动修改是计算机编程中,在一项的值变化时,其依赖项的值随之变化的行为模式。与惰性求值(Lazy Evaluation,又译为惰性计算、懒惰求值)相对。 假设数据项A的值依赖于数据项B的值。即B的值发生变化将导致A的值的变化。主动修改是在B变化后立即修改A。被动修改或称惰性求值是在取A的值时才修改A。一个具体例子是对于GUI应用程序,子菜单项的内容列表依赖于程序的状态,可以在程序状态改变时立即修改子菜单的列表(主动修改),也可以在仅当菜单被调用时才修改(被动修改)。 另一个例子是:可以在底层数据改变时立即修改视觉显示,也可以仅在点击"redraw"按钮后修改。 事务处理中的直接修改与延迟修改也是这种例子。 (zh)
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dbo:wikiPageID
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dbo:wikiPageLength
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- 2003 (xsd:nonNegativeInteger)
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dbo:wikiPageRevisionID
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dbo:wikiPageWikiLink
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dbp:wikiPageUsesTemplate
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dcterms:subject
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rdfs:comment
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- 主动修改是计算机编程中,在一项的值变化时,其依赖项的值随之变化的行为模式。与惰性求值(Lazy Evaluation,又译为惰性计算、懒惰求值)相对。 假设数据项A的值依赖于数据项B的值。即B的值发生变化将导致A的值的变化。主动修改是在B变化后立即修改A。被动修改或称惰性求值是在取A的值时才修改A。一个具体例子是对于GUI应用程序,子菜单项的内容列表依赖于程序的状态,可以在程序状态改变时立即修改子菜单的列表(主动修改),也可以在仅当菜单被调用时才修改(被动修改)。 另一个例子是:可以在底层数据改变时立即修改视觉显示,也可以仅在点击"redraw"按钮后修改。 事务处理中的直接修改与延迟修改也是这种例子。 (zh)
- In computer programming, suppose we have a data item A whose value depends on data item B, i.e., the value of A must be changed after the value of B changes and before the value of A becomes necessary. Active updating is updating A immediately after B changes, while passive updating or lazy updating (lazy evaluation) is updating A immediately before its value is fetched. And example of this distinction is, e.g., in the implementation of GUI applications: the list of submenu items may depend on the state of the application; this list may be updated either as soon as the state of the application changes ("active") or only when the menu is invoked ("passive"). (en)
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rdfs:label
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- Active updating (en)
- 主动修改 (zh)
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prov:wasDerivedFrom
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foaf:isPrimaryTopicOf
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is dbo:wikiPageWikiLink
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