org.picocontainer
Interface ComponentAdapter

All Known Implementing Classes:

DecoratingComponentAdapter, MonitoringComponentAdapter

public interface ComponentAdapter

A component adapter is responsible for providing a specific component instance. An instance of an implementation of this interface is used inside a PicoContainer for every registered component or instance. Each ComponentAdapter instance has to have a key which is unique within that container. The key itself is either a class type (normally an interface) or an identifier.

Since:

1.0

Version:

$Revision: 1801 $

Author:

Jon Tirsén, Paul Hammant, Aslak Hellesøy

See Also:

an extension of the PicoContainer interface which allows you to modify the contents of the container.

Method Summary

void	accept(PicoVisitor visitor) Accepts a visitor for this ComponentAdapter.
Class	getComponentImplementation() Retrieve the class of the component.
Object	getComponentInstance(PicoContainer container) Retrieve the component instance.
Object	getComponentKey() Retrieve the key associated with the component.
void	verify(PicoContainer container) Verify that all dependencies for this adapter can be satisifed.

Method Detail

getComponentKey

public Object getComponentKey()

Retrieve the key associated with the component.

Returns:

the component's key. Should either be a class type (normally an interface) or an identifier that is unique (within the scope of the current PicoContainer).

getComponentImplementation

public Class getComponentImplementation()

Retrieve the class of the component.

Returns:

the component's implementation class. Should normally be a concrete class (ie, a class that can be instantiated).

getComponentInstance

public Object getComponentInstance(PicoContainer container)
                            throws PicoInitializationException,
                                   PicoIntrospectionException

Retrieve the component instance. This method will usually create a new instance each time it is called, but that is not required. For example, CachingComponentAdapter will always return the same instance.

Parameters:

container - the PicoContainer, that is used to resolve any possible dependencies of the instance.

Returns:

the component instance.

Throws:

PicoInitializationException - if the component could not be instantiated.

PicoIntrospectionException - if the component has dependencies which could not be resolved, or instantiation of the component lead to an ambigous situation within the container.

verify

public void verify(PicoContainer container)
            throws PicoIntrospectionException

Verify that all dependencies for this adapter can be satisifed. Normally, the adapter should verify this by checking that the associated PicoContainer contains all the needed dependnecies.

Parameters:

container - the PicoContainer, that is used to resolve any possible dependencies of the instance.

Throws:

PicoIntrospectionException - if one or more dependencies cannot be resolved.

accept

public void accept(PicoVisitor visitor)

Accepts a visitor for this ComponentAdapter. The method is normally called by visiting a PicoContainer, that cascades the visitor also down to all its ComponentAdapter instances.

Parameters:

visitor - the visitor.

Since:

1.1