实现“脏”标志功能的不同方式 [英] Different ways to implement 'dirty'-flag functionality

问题描述

几乎每个程序员都在他的生活中做了一次：如果一个变量的值改变，设置一些标志。总有很多财产，如果有变化，您希望跟踪

1. 在任何财产中


2. 在特定的属性


3. 或某些属性集

我是有兴趣在上述情况中实现脏标志功能的不同方式，除了在每个属性更改上更新的标准对象宽脏标志。在每个设置器中必须有一个比dirty = true更好的东西：它看起来很丑陋，是一件乏味的工作。

解决方案

对于我的DAO，我保留从数据库检索的原始值的副本。当我发送它进行更新时，我只是将原始值与当前值进行比较。它在处理上花了一点钱，但是比每个属性都有一个脏标志好多了。

编辑进一步证明没有脏标记：如果属性返回它的原始价值，没有办法反映，肮脏的旗帜继续肮脏，因为原始的价值损失。

Almost every programmer did it once in his life: setting some flag if a variable's value changed. There's always lots of properties and you want to keep track if something changed

1. in any property
2. in a specific property
3. or in some set of properties

I'm interested in different ways to implement the "dirty-flag" functionality for the above situations, besides the standard object wide dirty flag being updated on each property change. There must be something better than putting "dirty = true" in each setter: it just looks ugly and is a tedious work.

解决方案

For my DAO I keep a copy of the original values as retrieved from the database. When I send it to be updated, I simply compare the original values with the current. It costs a little in processing but it is a lot better than having a dirty flag per property.

EDIT to further justify not having a dirty flag: if the property returns to its original value, there is no way to reflect that, the dirty flag continues dirty because the original value was lost.

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