OCAF——框架机制

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OCAF Architecture Overview

OCAF provides you with an object-oriented Application-Document-Attribute model consisting of C++ class libraries.

 这里涉及重要的4个概念：Application、Document、Attribute和Reference-key model

本文将重点描述Reference-key model机制：

1. Application

   1. Application是一个抽象类，负责在工作期间处理documents

   2. 创建新的documents

   3. 存储documents

   4. 打开documents

   5. 初始化document的views

2. Document

   1. "Application data"的容器

   2. The document is the container for the application data.

   3. The document is implemented by the concreate class : Document.

   4. Documents offer access to the data framework and serve the following purposes

      1. Manage the notification of changes 管理变更

      2. Update external links 管理关联关系

      3. Manage the saving and restoring of data 管理序列化和反序列化

      4. Store the names of software extensions. 存储软件扩展

      5. Manage command transactions. 管理命令事务

      6. Manage Undo and Redo options.管理Undo和Redo

   5. Each document is saved in a single flat ASCII file defined by its format and extension (a ready-to-use format is provided with OCAF)

   6. 除了作为应用程序数据容器的角色外，文档还可以相互引用；例如，文档 A 可以引用文档 B 中的特定标签。通过引用键可以实现此功能。

3. Attribute

   1. “Application data” is described by Attributes, which are instances of classes derived from the Attribute abstract class.

   2. The OCAF Data Framework references aggregations of attributes using persistent identifiers in a single hierarchy.

      1. Attribute是一个抽象类

      2. OCAF数据框架是一个引用属性的聚合aggregations

      3. OCAF