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6.6.5.0.3: Assembly properties for method extensions

6.6.5.0.3: Assembly properties for method extensions

Method type
Specifies the type of the enterprise bean method. Valid values are Home methods, Remote methods, and All methods.

Name
Specifies the name of an enterprise bean method, or the asterisk character (*) . The asterisk is used to denote all the methods of the specified interface--for example, all methods in the remote interface.

Parameters
Contains a list of fully qualified Java type names of the method parameters. Used to identify a single method among multiple methods with an overloaded method name.

Isolation level attributes
The transaction isolation level determines how isolated one transaction is from another. This property can be set for individual methods in an enterprise bean or for all methods in the enterprise bean. An asterisk is used to indicate all methods in the bean. However, within a transactional context, the isolation level associated with the first method invocation becomes the required isolation level for all methods invoked within that transaction. If a method is invoked with a different isolation level from that of the first method, the java.rmi.RemoteException exception is thrown.

Isolation level
Specifies the level of transactional isolation. The valid values are as follows:

  • Serializable. This level prohibits the following types of reads:

    • Dirty reads, where a transaction reads a database row containing uncommitted changes from a second transaction.

    • Nonrepeatable reads, where one transaction reads a row, a second transaction changes the same row, and the first transaction rereads the row and gets a different value.

    • Phantom reads, where one transaction reads all rows that satisfy an SQL WHERE condition, a second transaction inserts a row that also satisfies the WHERE condition, and the first transaction applies the same WHERE condition and gets the row inserted by the second transaction.

  • Repeatable read. This level prohibits dirty reads and nonrepeatable reads, but it allows phantom reads.

  • Read committed. This level prohibits dirty reads, but allows nonrepeatable reads and phantom reads.

  • Read uncommitted. This level allows dirty reads, nonrepeatable reads, and phantom reads.

The container uses the transaction isolation level attribute as follows:

  • Session beans and entity beans with bean-managed persistence (BMP)--For each database connection used by the bean, the container sets the transaction isolation level at the start of each transaction unless the bean explicitly sets the isolation level on the connection.

  • Entity beans with container-managed persistence (CMP)--The container generates database access code that implements the specified isolation level.

Security Identity
Specifies that a principal's credential properties are to be handled as indicated in the Run-As mode property. Checking this box makes the Run-as Mode properties editable.

Description
Contains text describing or commenting on the security instructions.

Run-As Mode
Credential information is used by the security service to determine the permissions that a principal has on various resources. At appropriate points, the security service determines whether the principal is authorized to use a particular resource based on the principal's permissions. If the method invocation is authorized, the security service does the following with the principal's credential properties based on the value of the Run-as Mode property of the enterprise bean:

  • Use Identity of Caller -- the security service makes no changes to the principal's credential properties.

  • Use Identity of EJB Server -- the security service alters the principals credential properties to match the credential properties associated with the EJB server.

  • Use Identity Assigned to Specified Role -- A principal that has been assigned to the specified security role is used for the execution of the bean's methods. This association is part of the application binding where the role is associated with a user ID and password of a user who is granted that role.

Role Name
Specifies the name of a security role. If the Use Identity Assigned to Specified Role button is selected, a principal that has been granted this role will be used.

Description
Contains a description of the security role.

Access Intent - Intent type
Specifies whether the method is a read-only method or whether the method can update data (or invoke other methods that can update data, in the same transaction). The legal values are read or update (read/write).

Finder descriptor - User
Specifies that the user has provided a finder helper class in the entity bean's home interface. The class contains specialized finder methods.

Finder descriptor - EJB QL

Describes the semantics of a finder method using the EJB QL (Enterprise JavaBeans query language). EJB QL is a declarative, SQL-like language intended to be compiled to the target language of the persistent data store used by a persistence manager. The language is independent of the bean's mapping to a relational datastore and is therefore portable. The EJB query specifies a search based on the persistent attributes and relationships of the bean. An EJB query contains a SELECT clause (optional), a FROM clause (required), a WHERE clause (optional), and an ORDER BY clause (optional). The SELECT clause specifies the EJB objects to return. The FROM clause specifies the collections of objects to which the query is to be applied. The WHERE clause contains search predicates over the collections. The ORDER BY clause specifies the ordering of the resulting collection.

Finder descriptor - Where clause

Describes the semantics of the finder method using an SQL WHERE clause. This clause restricts the results that are returned by the query.

For information on restrictions, see the documentation for Deployment Tool for Enterprise JavaBeans.

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