org.araneaframework.core
Class BaseComponent

java.lang.Object
  org.araneaframework.core.BaseComponent

All Implemented Interfaces:

Serializable, Component

Direct Known Subclasses:

BaseApplicationComponent, BaseService, StandardServletServiceAdapterComponent

public class BaseComponent
extends Object
implements Component

The base class for all Aranea components. Base entities do not make a Composite pattern and only provide some very basic services (mainly syncronization and messaging service)

Author:

"Toomas Römer" , Jevgeni Kabanov (ekabanov at araneaframework dot org)

See Also:

Serialized Form

Nested Class Summary

protected class

BaseComponent.ComponentImpl

Nested classes/interfaces inherited from interface org.araneaframework.Component

Component.Interface

Constructor Summary

BaseComponent()

Method Summary

protected void	_addComponent(Object key, Component component, Environment env) Adds a child component to this component with the key and initilizes it with the specified Environment env.
protected void	_addComponent(Object key, Component component, Scope scope, Environment env) Adds a child component to this component with the key and initilizes it with the specified Environment env.
protected void	_checkCall() Checks if this component was initialized.
protected void	_disableComponent(Object key) Disables the child component with the specified key.
protected void	_enableComponent(Object key) Enables a disabled child component with the specified key.
protected void	_endCall() Decrements the call count.
protected void	_endWaitingCall() Decrements internal callcount counter.
protected Map	_getChildren() Returns the children of this component.
Component.Interface	_getComponent() The factory method returning the implementation of the Component.
protected Map	_getDisabledChildren() Returns the children of this component.
protected void	_propagate(Message message) Forwards the message to the component and to all of its children components.
protected void	_relocateComponent(Composite parent, Environment newEnv, Object keyFrom, Object keyTo) Relocates parent's child with keyFrom to this BaseComponent with a new key keyTo.
protected void	_removeComponent(Object key) Removes the child component with the specified key from the children and calls destroy on it.
protected void	_setEnvironment(Environment env) Sets the environment of this component to env.
protected void	_setScope(Scope scope) Sets the scope for this component.
protected void	_startCall() Checks if a call is valid (component is in the required state), increments the call count.
protected void	_startWaitingCall() Used for starting a call that is a re-entrant call.
protected void	_strictCheckCall() Checks if this component is currently alive.
protected void	_strictStartCall()
protected void	_waitNoCall() Waits until no call is made to the component.
protected void	destroy() Destroy callback.
protected void	disable() Disables the component.
protected void	enable() Enables the component.
Environment	getEnvironment() Provides access to the Environment of this Component.
Scope	getScope() Provides the scope of this Component.
protected void	handleException(Exception e) Handles any given exception.
protected void	init() Init callback.
boolean	isAlive() Specifies whether this Component is alive.
boolean	isDead() Specifies whether the component is dead.
boolean	isInitialized() Gets whether the component has been initialized.
protected void	propagate(Message message) Forwards the message to the component and to all of its children components.

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseComponent

public BaseComponent()

Method Detail

_getComponent

public Component.Interface _getComponent()

Description copied from interface: Component

The factory method returning the implementation of the Component.

Specified by:

_getComponent in interface Component

Returns:

the implementation of the Component.

init

protected void init()
             throws Exception

Init callback. Gets called when the component is initilized.

Throws:

Exception - Any runtime exception that may occur.

destroy

protected void destroy()
                throws Exception

Destroy callback. Gets called when the component is destroyed.

Throws:

Exception - Any runtime exception that may occur.

disable

protected void disable()
                throws Exception

Disables the component.

Throws:

Exception - Any runtime exception that may occur.

enable

protected void enable()
               throws Exception

Enables the component.

Throws:

Exception - Any runtime exception that may occur.

propagate

protected void propagate(Message message)
                  throws Exception

Forwards the message to the component and to all of its children components.

Parameters:

message - A message to forward.

Throws:

Exception - Any runtime exception that may occur.

handleException

protected void handleException(Exception e)
                        throws Exception

Handles any given exception.

Parameters:

e - The exception that occured.

Throws:

Exception - Any runtime exception that may occur during error handling.

getEnvironment

public Environment getEnvironment()

Description copied from interface: Component

Provides access to the Environment of this Component.

Specified by:

getEnvironment in interface Component

Returns:

the Environment of the Component.

getScope

public Scope getScope()

Description copied from interface: Component

Provides the scope of this Component. The Scope is related to Path and the idea behind it is quite similar.

Specified by:

getScope in interface Component

Returns:

the scope of the Component

isInitialized

public boolean isInitialized()

Gets whether the component has been initialized. "Initialized" means that the init() method has been called.

Returns:

true, if the component has been initialized.

isAlive

public boolean isAlive()

Description copied from interface: Component

Specifies whether this Component is alive. If it is alive then it means that the Component has been initialized and is not destroyed yet.

Specified by:

isAlive in interface Component

Returns:

true, if this component has been initialized and is not destroyed. Otherwise, false.

isDead

public boolean isDead()

Specifies whether the component is dead. It means that the destroy() method has been called.

Returns:

true, if the component has been destroyed.

_setEnvironment

protected void _setEnvironment(Environment env)

Sets the environment of this component to env.

Parameters:

env - The new Envrionment for this component.

_setScope

protected void _setScope(Scope scope)

Sets the scope for this component.

Parameters:

scope - the new scope to identify this component.

Since:

1.1

_waitNoCall

protected void _waitNoCall()
                    throws InterruptedException

Waits until no call is made to the component. Used to synchronize calls to the component.

Throws:

InterruptedException

_startCall

protected void _startCall()
                   throws IllegalStateException

Checks if a call is valid (component is in the required state), increments the call count.

Throws:

IllegalStateException

_strictStartCall

protected void _strictStartCall()
                         throws IllegalStateException

Throws:

IllegalStateException

Since:

1.1

_endCall

protected void _endCall()

Decrements the call count. Wakes up all threads that are waiting on this object's monitor

_startWaitingCall

protected void _startWaitingCall()

Used for starting a call that is a re-entrant call. Meaning a call of this component is doing the calling

_endWaitingCall

protected void _endWaitingCall()

Decrements internal callcount counter.

_checkCall

protected void _checkCall()
                   throws IllegalStateException

Checks if this component was initialized. If not, throws IllegalStateException. This is relatively loose check, allowing leftover calls to dead components.

Throws:

IllegalStateException - when component has never been initialized

_strictCheckCall

protected void _strictCheckCall()
                         throws IllegalStateException

Checks if this component is currently alive. This is strict check that disallows leftover calls to dead components.

Throws:

IllegalStateException - when component is unborn or dead

Since:

1.1

_getChildren

protected Map _getChildren()

Returns the children of this component.

_getDisabledChildren

protected Map _getDisabledChildren()

Returns the children of this component.

_addComponent

protected void _addComponent(Object key,
                             Component component,
                             Environment env)

Adds a child component to this component with the key and initilizes it with the specified Environment env.

_addComponent

protected void _addComponent(Object key,
                             Component component,
                             Scope scope,
                             Environment env)

Adds a child component to this component with the key and initilizes it with the specified Environment env.

Since:

1.1

_removeComponent

protected void _removeComponent(Object key)

Removes the child component with the specified key from the children and calls destroy on it.

Parameters:

key - The ID of the component to remove.

_disableComponent

protected void _disableComponent(Object key)

Disables the child component with the specified key. A disabled child is a child that is removed from the standard set of children

Parameters:

key - The ID of the child component to disable.

_enableComponent

protected void _enableComponent(Object key)

Enables a disabled child component with the specified key. If the key does not correspond to anything, a runtime exception will occur.

Parameters:

key - The ID of the child component to enable.

_relocateComponent

protected void _relocateComponent(Composite parent,
                                  Environment newEnv,
                                  Object keyFrom,
                                  Object keyTo)

Relocates parent's child with keyFrom to this BaseComponent with a new key keyTo. The child will get the Environment specified by newEnv.

Parameters:

parent - is the current parent of the child to be relocated.

newEnv - the new Environment of the child.

keyFrom - is the key of the child to be relocated.

keyTo - is the the key, with which the child will be added to this StandardService.

_propagate

protected void _propagate(Message message)

Forwards the message to the component and to all of its children components.

Note: this is the component propagation logic that should not be modified by applications (they should use just the propagate(Message)).

Parameters:

message - A message to forward.

Throws:

Exception - Any runtime exception that may occur.