org.openide.cookies

Interface InstanceCookie

All Superinterfaces:

Node.Cookie

All Known Subinterfaces:

InstanceCookie.Of

public interface InstanceCookie
extends Node.Cookie

Cookie that should be provided by all nodes that are able to create or return an "instance". Generally this is used to register objects declaratively in XML layers. The most commonly used implementation seems to be InstanceDataObject.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	InstanceCookie.Of Enhanced cookie that can answer queries about the type of the instance it creates.

Method Summary

Methods

Modifier and Type	Method and Description
Class<?>	instanceClass() The type that the instance is expected to be assignable to.
Object	instanceCreate() Create or obtain an instance.
String	instanceName() The name of instanceClass().

Method Detail

instanceName

String instanceName()

The name of instanceClass(). Should be the same as instanceClass().getName() but may be able to avoid actually loading the class.

Generally this method should not be used.

Returns:

the instance class name

instanceClass

Class<?> instanceClass()
                       throws IOException,
                              ClassNotFoundException

The type that the instance is expected to be assignable to. Can be used to test whether the instance is of an appropriate class without actually creating it.

Generally this method should not be used. To test whether the instance will be assignable to some type, use InstanceCookie.Of.instanceOf(java.lang.Class<?>) instead. To actually load instances, use instanceCreate(); if your objects are not naturally singletons (e.g. public no-argument constructor), the instances should rather be of some kind of factory you define.

Returns:

the type (or perhaps some interesting supertype) of the instance

Throws:

IOException - if metadata about the instance could not be read, etc.

ClassNotFoundException - if the instance type could not be loaded

instanceCreate

Object instanceCreate()
                      throws IOException,
                             ClassNotFoundException

Create or obtain an instance. For example InstanceDataObject (one of the most often used implementations of InstanceCookie) caches previously returned instances.

Returns:

an object assignable to instanceClass()

Throws:

IOException - for the same reasons as instanceClass(), or an object could not be deserialized, etc.

ClassNotFoundException - for the same reasons as instanceClass()