org.picocontainer.adapters
Class AbstractAdapter<T>

java.lang.Object
  org.picocontainer.adapters.AbstractAdapter<T>

All Implemented Interfaces:

Serializable, ComponentAdapter<T>, ComponentMonitorStrategy

Direct Known Subclasses:

AbstractInjector, DefaultPicoContainer.LateInstance, InstanceAdapter

public abstract class AbstractAdapter<T>
extends Object
implements ComponentAdapter<T>, ComponentMonitorStrategy, Serializable

Base class for a ComponentAdapter with general functionality. This implementation provides basic checks for a healthy implementation of a ComponentAdapter. It does not allow to use null for the component key or the implementation, ensures that the implementation is a concrete class and that the key is assignable from the implementation if the key represents a type.

Author:

Paul Hammant, Aslak Hellesøy, Jon Tirsén

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.picocontainer.ComponentAdapter

ComponentAdapter.NOTHING

Constructor Summary

AbstractAdapter(Object componentKey, Class componentImplementation)
Constructs a new ComponentAdapter for the given key and implementation.

AbstractAdapter(Object componentKey, Class componentImplementation, ComponentMonitor monitor)
Constructs a new ComponentAdapter for the given key and implementation.

Method Summary

void	accept(PicoVisitor visitor) Accepts a visitor for this ComponentAdapter.
void	changeMonitor(ComponentMonitor monitor) Changes the component monitor used
protected void	checkTypeCompatibility()
ComponentMonitor	currentMonitor() Returns the monitor currently used
<U extends ComponentAdapter> U	findAdapterOfType(Class<U> adapterType) Locates a component adapter of type componentAdapterType in the ComponentAdapter chain.
Class<T>	getComponentImplementation() Retrieve the class of the component.
T	getComponentInstance(PicoContainer container) Retrieve the component instance.
Object	getComponentKey() Retrieve the key associated with the component.
ComponentAdapter<T>	getDelegate() Component adapters may be nested in a chain, and this method is used to grab the next ComponentAdapter in the chain.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.picocontainer.ComponentAdapter

getComponentInstance, getDescriptor, verify

Constructor Detail

AbstractAdapter

public AbstractAdapter(Object componentKey,
                       Class componentImplementation)

Constructs a new ComponentAdapter for the given key and implementation.

Parameters:

componentKey - the search key for this implementation

componentImplementation - the concrete implementation

AbstractAdapter

public AbstractAdapter(Object componentKey,
                       Class componentImplementation,
                       ComponentMonitor monitor)

Constructs a new ComponentAdapter for the given key and implementation.

Parameters:

componentKey - the search key for this implementation

componentImplementation - the concrete implementation

monitor - the component monitor used by this ComponentAdapter

Method Detail

getComponentKey

public Object getComponentKey()

Retrieve the key associated with the component.

Specified by:

getComponentKey in interface ComponentAdapter<T>

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).

See Also:

ComponentAdapter.getComponentKey()

getComponentImplementation

public Class<T> getComponentImplementation()

Retrieve the class of the component.

Specified by:

getComponentImplementation in interface ComponentAdapter<T>

Returns:

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

See Also:

ComponentAdapter.getComponentImplementation()

checkTypeCompatibility

protected void checkTypeCompatibility()

getComponentInstance

public T getComponentInstance(PicoContainer container)
                       throws PicoCompositionException

Description copied from interface: ComponentAdapter

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

Specified by:

getComponentInstance in interface ComponentAdapter<T>

Parameters:

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

Returns:

the component instance.

Throws:

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

toString

public String toString()

Overrides:

toString in class Object

Returns:

Returns the ComponentAdapter's class name and the component's key.

See Also:

Object.toString()

accept

public void accept(PicoVisitor visitor)

Description copied from interface: ComponentAdapter

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.

Specified by:

accept in interface ComponentAdapter<T>

Parameters:

visitor - the visitor.

changeMonitor

public void changeMonitor(ComponentMonitor monitor)

Description copied from interface: ComponentMonitorStrategy

Changes the component monitor used

Specified by:

changeMonitor in interface ComponentMonitorStrategy

Parameters:

monitor - the new ComponentMonitor to use

currentMonitor

public ComponentMonitor currentMonitor()

Returns the monitor currently used

Specified by:

currentMonitor in interface ComponentMonitorStrategy

Returns:

The ComponentMonitor currently used

getDelegate

public final ComponentAdapter<T> getDelegate()

Description copied from interface: ComponentAdapter

Component adapters may be nested in a chain, and this method is used to grab the next ComponentAdapter in the chain.

Specified by:

getDelegate in interface ComponentAdapter<T>

Returns:

the next component adapter in line or null if there is no delegate ComponentAdapter.

findAdapterOfType

public final <U extends ComponentAdapter> U findAdapterOfType(Class<U> adapterType)

Description copied from interface: ComponentAdapter

Locates a component adapter of type componentAdapterType in the ComponentAdapter chain. Will return null if there is no adapter of the given type.

Specified by:

findAdapterOfType in interface ComponentAdapter<T>

Type Parameters:

U - the type of ComponentAdapter being located.

Parameters:

adapterType - the class of the adapter type being located. Never null.

Returns:

the appropriate component adapter of type U. May return null if the component adapter type is not returned.