开捕鱼机怎么入账

書(shū)名： Oracle JDeveloper 11gR2 Cookbook
作者名： Nick Haralabidis
本章字?jǐn)?shù)： 368字
更新時(shí)間： 2021-08-20 15:53:04

Using getPostedAttribute() to determine the posted attribute's value

There are times when you need to get the original database value of an entity object atttribute, such as when you want to compare the attribute's current value to the original database value. In this recipe, we will illustrate how to do this by utilizing the getPostedAttribute() method.

Getting ready

We will be working on the SharedComponets workspace. We will add a helper method to the custom entity framework class.

How to do it...

Start by opening the SharedComponets workspace. If needed, follow the steps in the referenced recipe to create it.
Locate the custom entity framework class and open it into the source editor.

Add the following code to the custom entity framework class:

/**
* Check if attribute's value differs from its posted value
* @param attrIdx the attribute index
* @return
*/
public boolean isAttrValueChanged(int attrIdx) {
  // get the attribute's posted value
  Object postedValue = getPostedAttribute(attrIdx);
  // get the attribute's current value
  Object newValue = getAttributeInternal(attrIdx);
  // return true if attribute value differs from its posted value
  return isAttributeChanged(attrIdx) &&((postedValue == null && newValue != null) ||(postedValue != null && newValue == null) ||(postedValue != null && newValue != null &&!newValue.equals(postedValue)));
}

How it works...

We added a helper method called isAttrValueChanged() to the our custom entity framework class. This method accepts the attribute's index. The attribute index is generated and maintained by JDeveloper itself. The method first calls getPostedAttribute() specifying the attribute index to retrieve the attribute value that was posted to the database. This is the attribute's database value. Then it calls getAttributeInternal() using the same attribute index to determine the current attribute value. The two values are then compared. The method isAttributeChanged() returns true if the attribute value was changed in the current transaction.

The following is an example of calling isAttrValueChanged() from an entity implementation class to determine whether the current value of the employee's last name differs from the value that was posted to the database:

super.isAttrValueChanged(this.LASTNAME);

官术网_书友最值得收藏!

Using getPostedAttribute() to determine the posted attribute's value

Getting ready

How to do it...

How it works...

See also

官术网_书友最值得收藏!

Oracle JDeveloper 11gR2 Cookbook

Using getPostedAttribute() to determine the posted attribute's value

Getting ready

How to do it...

How it works...

See also