| 摘要 |
A method of executing a task in a manner that verifies that performance of the task will likely be successful. This may be accomplished using a task object that specifies one or more preconditions that must be satisfied in order for the task to be successful. The preconditions are verified using condition objects. If the preconditions are not satisfied, the task fails before its execution even began. On the other hand, if the preconditions are satisfied, the task is executed. This may be accomplished by, for example, calling an execution method of the task object. If the execution fails, the task may be undone by, for example, calling a compensation method of the task object. After execution, one or more postconditions may be verified in a similar manner. If the postconditions are not satisfied, then the compensation method may be called in that circumstance as well.
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