F ADF Equivalents of Common Oracle Forms Triggers

This appendix provides a summary of how basic tasks performed with the most common Oracle Forms triggers are accomplished using Oracle ADF.

This appendix includes the following sections:

F.1 Validation and Defaulting (Business Logic)

You will learn how Oracle Forms Validation and Defaulting Triggers are performed using Oracle ADF equivalents.

Table F-1 ADF Equivalents for Oracle Forms Validation and Defaulting Triggers

Forms Trigger	ADF Equivalent
`WHEN-VALIDATE-RECORD` Execute validation code at the record level	In the custom `EntityImpl` class for your entity object, write a public method returning a `boolean` type with a method name like `validateXXXX()` and have it return `true` if the validation succeeds or `false` if the validation fails. Then, add a Method validator for this validation method to your entity object at the entity level. When doing that, you can associate a validation failure message with the rule.
`WHEN-VALIDATE-ITEM` Execute validation code at the field level	In the custom `EntityImpl` class for your entity object, write a public method returning a `boolean` type and accepting a single argument of the same data type as your attribute, having a method name like `validateXXXX()`. Have it return `true` if the validation succeeds or `false` if the validation fails. Then, add a Method validator for this validation method to the entity object at the attribute level for the appropriate attribute. When doing that, you can associate a validation failure message with the rule.
`WHEN-DATABASE-RECORD` Execute code when a row in the data block is marked for insert or update	Override the `addToTransactionManager()` method of your entity object. Write code after calling the super.
`WHEN-CREATE-RECORD` Execute code to populate complex default values when a new record in the data block is created, without changing the modification status of the record	Override the `create()` method of your entity object and after calling the super, use appropriate `setAttrName()` methods to set default values for attributes as necessary. To immediately set a primary key attribute to the value of a sequence, construct an instance of the `SequenceImpl` helper class and call its `getSequenceNumber()` method to get the next sequence number. Assign this value to your primary key attribute. If you want to wait to assign the sequence number until the new record is saved, but still without using a database trigger, you can use this technique in an overridden `prepareForDML()` method in your entity object. If instead you want to assign the primary key from a sequence using your own `BEFOREINSERTFOREACHROW` database trigger, then use the special data type called `DBSequence` for your primary key attribute instead of the regular `Number` type.
`WHEN-REMOVE-RECORD` Execute code whenever a row is removed from the data block	Override the `remove()` method of your entity object and write code either before or after calling the super.

F.2 Query Processing

You will learn how Oracle Forms Query Processing Triggers are performed using Oracle ADF equivalents.

Table F-2 ADF Equivalents for Oracle Forms Query Processing Triggers

Forms Trigger	ADF Equivalent
`PRE-QUERY` Execute logic before executing a query in a data block, typically to set up values for Query-by-Example criteria in the "example record"	Override the `executeQueryForCollection()` method on your view object class and write code before calling the super.
`ON-COUNT` Override default behavior to count the query hits for a data block	Override the `getQueryHitCount()` method in your view object and do something instead of calling the super.
`POST-QUERY` Execute logic after retrieving each row from the data source for a data block.	Generally instead of using a `POST-QUERY` style technique to fetch descriptions from other tables based on foreign key values in the current row, in ADF it's more efficient to build a view object that has multiple participating entity objects, joining in all the information you need in the query from the main table, as well as any auxiliary or lookup-value tables. This way, in a single roundtrip to the database you get all the information you need. If you still need a per-fetched-row trigger like `POST-QUERY`, override the `createInstanceFromResultSet()` method in your view object class.
`ON-LOCK` Override default behavior to attempt to acquire a lock on the current row in the data block	Override the `lock()` method in your entity object class and do something instead of calling the super.

F.3 Database Connection

You will learn how Oracle Forms Database Connection Triggers are performed using Oracle ADF equivalents.

Table F-3 ADF Equivalents for Oracle Forms Database Connection Triggers

Forms Trigger ADF Equivalent

Forms Trigger	ADF Equivalent
`POST-LOGON` Execute logic after logging into the database	Override the `afterConnect()` method on your custom application module. Since an application module instance can stay connected while serving different logical client sessions, you can override the `prepareSession()` method, which is fired after initial login, as well as after any time the application module is accessed by a user that was different from the one that accessed it last time.
`PRE-LOGOUT` Execute logic before logging out of the database	Override the `beforeDisconnect()` method on your custom application module class.

POST-LOGON

Execute logic after logging into the database

Override the afterConnect() method on your custom application module. Since an application module instance can stay connected while serving different logical client sessions, you can override the prepareSession() method, which is fired after initial login, as well as after any time the application module is accessed by a user that was different from the one that accessed it last time.

PRE-LOGOUT

Execute logic before logging out of the database

Override the beforeDisconnect() method on your custom application module class.

F.4 Transaction "Post" Processing (Record Cache)

You will learn how Oracle Forms Transactional Processing Triggers are performed using Oracle ADF equivalents.

Table F-4 ADF Equivalents for Oracle Forms Transactional Triggers

Forms Trigger ADF Equivalent

Forms Trigger	ADF Equivalent
`PRE-COMMIT` Execute code before commencing processing of the changed rows in all data blocks in the transaction	Override the `commit()` method in a custom `DBTransactionImpl` class and write code before calling the super. Note: For an overview of creating and using a custom `DBTransaction` implementation, see Creating a Custom Database Transaction Framework Extension Class.
`PRE-INSERT` Execute code before a new row in the data block is inserted into the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_INSERT`, then write code before calling the super.
`ON-INSERT` Override default processing for inserting a new row into the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_INSERT`, then write code instead of calling the super.
`POST-INSERT` Execute code after new row in the data block is inserted into the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_INSERT`, then write code after calling the super.
`PRE-DELETE` Execute code before a row removed from the data block is deleted from the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_DELETE`, then write code before calling the super.
`ON-DELETE` Override default processing for deleting a row removed from the data block from the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_DELETE`, then write code instead of calling the super.
`POST-DELETE` Execute code after a row removed from the data block is deleted from the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_DELETE`, then write code after calling the super.
`PRE-UPDATE` Execute code before a row changed in the data block is updated in the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_UPDATE`, then write code before calling the super.
`ON-UPDATE` Override default processing for updating a row changed in the data block from the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_UPDATE`, then write code instead of calling the super.
`POST-UPDATE` Execute code after a row changed in the data block is updated in the database during "post" processing	Override the `doDML()` method in your entity class, and if the `operation` equals `DML_UPDATE`, then write code after calling the super.
`POST-FORMS-COMMIT` Execute code after Forms has "posted" all necessary rows to the database, but before issuing the data commit to end the transaction	If you want a single block of code for the whole transaction, you can override the `doCommit()` method in a custom `DBTransactionImpl` object and write code before calling the super. To execute entity-specific code before commit for each affected entity in the transaction, override the `beforeCommit()` method on your entity object, and write code there.
`POST-DATABASE-COMMIT` Execute code after database transaction has been committed	Override the `commit()` method in a custom `DBTransactionImpl` class, and write code after calling the super.

PRE-COMMIT

Execute code before commencing processing of the changed rows in all data blocks in the transaction

Override the commit() method in a custom DBTransactionImpl class and write code before calling the super.

Note:

For an overview of creating and using a custom DBTransaction implementation, see Creating a Custom Database Transaction Framework Extension Class.

PRE-INSERT

Execute code before a new row in the data block is inserted into the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_INSERT, then write code before calling the super.

ON-INSERT

Override default processing for inserting a new row into the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_INSERT, then write code instead of calling the super.

POST-INSERT

Execute code after new row in the data block is inserted into the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_INSERT, then write code after calling the super.

PRE-DELETE

Execute code before a row removed from the data block is deleted from the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_DELETE, then write code before calling the super.

ON-DELETE

Override default processing for deleting a row removed from the data block from the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_DELETE, then write code instead of calling the super.

POST-DELETE

Execute code after a row removed from the data block is deleted from the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_DELETE, then write code after calling the super.

PRE-UPDATE

Execute code before a row changed in the data block is updated in the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_UPDATE, then write code before calling the super.

ON-UPDATE

Override default processing for updating a row changed in the data block from the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_UPDATE, then write code instead of calling the super.

POST-UPDATE

Execute code after a row changed in the data block is updated in the database during "post" processing

Override the doDML() method in your entity class, and if the operation equals DML_UPDATE, then write code after calling the super.

POST-FORMS-COMMIT

Execute code after Forms has "posted" all necessary rows to the database, but before issuing the data commit to end the transaction

If you want a single block of code for the whole transaction, you can override the doCommit() method in a custom DBTransactionImpl object and write code before calling the super.

To execute entity-specific code before commit for each affected entity in the transaction, override the beforeCommit() method on your entity object, and write code there.

POST-DATABASE-COMMIT

Execute code after database transaction has been committed

Override the commit() method in a custom DBTransactionImpl class, and write code after calling the super.

F.5 Error Handling

You will learn how Oracle Forms Error Handling Triggers are performed using Oracle ADF equivalents.

Table F-5 ADF Equivalents for Oracle Forms Error Handling Triggers

Forms Trigger ADF Equivalent

Forms Trigger	ADF Equivalent
`ON-ERROR` Override default behavior for handling an error	Install a custom error handler (`DCErrorHandler`) on the ADF `BindingContext`.

ON-ERROR

Override default behavior for handling an error

Install a custom error handler (DCErrorHandler) on the ADF BindingContext.