Before using the importer for the first time, you should read this section to understand how Java methods are mapped to EAServer component methods.
Each method in a class or interface (including those inherited from a base class or interface) is inspected to see if they use allowable parameter and return types. Suitable methods are added to the component’s IDL interface. EAServer Manager displays warning dialog boxes describing any methods that are not imported. The importer accepts methods that use the following datatypes:
Java equivalents for the predefined
EAServer datatypes “Choose implementation datatypes” describes
the Java equivalents for the predefined EAServer datatypes. If your
component uses the IDL/Java datatype mappings, the importer
sets the Component Type field to Java/IDL.
Otherwise, the Component Type field is set to Java/JDBC.
If you import a class that ran as an EAServer version 1.1 component,
it will be assigned the Java/JDBC component
type.
An inout parameter must use the holder classes as described in “Choose implementation datatypes”.
User-defined classes With restrictions, user-defined classes are allowed as parameters or return types. The importer creates an IDL definition to match the class. User-defined classes must contain only fields (no methods). Fields may use the Java equivalents for predefined EAServer datatypes, as described above.
For an inout parameter, the Java method definition must use a holder class that you have created, as described in “Holders for user-defined classes and arrays”.
Single-dimension arrays Single-dimension arrays are allowed as parameters or return types. The base type can be any Java equivalent for the predefined EAServer types or a user-defined class. (User-defined classes are subject to the restrictions noted above.)
For an inout parameter, the Java method definition must use a holder class that you have created as described in “Holders for user-defined classes and arrays”.
The method can throw any exception, but only exceptions that extend org.omg.CORBA.UserException are added to the IDL method’s raises clause.
Holders for user-defined classes and arrays For an inout parameter declared as a user-defined class or a single-dimension array, the Java method definition must use a holder class that you have created. For a user-defined class, the template for the holder class is as follows:
package comp-package;
class TypeHolder {
Type value;
// Default constructor:
TypeHolder();
// Initial-value constructor:
TypeHolder(Type value);
}
where
comp-package is the same package that contains the class or interface that you are importing.
Type is the user-defined class name.
For an array, the template for the holder class is as follows:
package comp-package;
class TypenameHolder {
BaseType value;
// Default constructor:
TypenameHolder();
// Initial-value constructor:
TypnameHolder(BaseType[] value);
}
where:
comp-package is the same package that contains the class or interface that you are importing.
Typename is a legal Java identifier. The importer will create an IDL typedef statement for the array type using this declaration.
BaseType is the base type for the array.
Methods to be imported from a Java interface must adhere to the restrictions described in “Determining eligible methods”. In addition, the interface cannot contain any fields.
You must specify a class that implements the interface before you can run the component. Specify the implementation class name in the Component Properties window (see “Component properties: General”). Make sure that the class has a default constructor (that is, a constructor with no arguments). EAServer calls the default constructor to create new component instances.
Methods to be imported from a Java class must adhere to the restrictions described in “Determining eligible methods”. In addition, the class must have a constructor method with zero parameters. Other constructors are not called by EAServer.
Classes that implement the ServerBean interface
can be imported. The ServerBean methods are not
added to the component’s IDL interface.
To import method definitions from a JavaBeans component, you choose the Java Class option on the import screen, then specify the name of the class that implements the component.
Methods to be imported from a JavaBeans component must adhere to the restrictions described in “Determining eligible methods”. In addition, the class must have a constructor method with zero parameters. Other constructors are not imported.
The add and remove methods for the JavaBeans event listeners are not imported.
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