org.sape.carbon.core.config.interceptor
Class DefaultConfigurationInterceptor

java.lang.Object
  |
  +--org.sape.carbon.core.util.reflection.GenericProxy
        |
        +--org.sape.carbon.core.config.interceptor.DefaultConfigurationInterceptor

All Implemented Interfaces:

ConfigurationInterceptor, Decorator, EventListener, Interceptor, InvocationHandler, NodeEventListener

public class DefaultConfigurationInterceptor

extends GenericProxy

implements ConfigurationInterceptor, Interceptor, NodeEventListener

The default implementation of ConfigurationInterceptor. This implementation is a java.lang.reflect.InvocationHandler that can handle method calls on both the ConfigurationInterceptor interface and the component's configuration interface. All set requests to the configuration interface manipulate the working configuration. All get requests to the configuration interface manipulate the live configuration. The ConfigurationInterceptor interface handles the management of the working and live configurations.

Copyright 2002 Sapient

Since:

carbon 1.0

Version:

$Revision: 1.6 $($Author: dvoet $ / $Date: 2003/10/27 19:54:41 $)

Author:

Greg Hinkle, January 2002

Field Summary

private static String	CLONE Name of the clone method.
private static Method	CONFIGURE_METHOD Holds a reference to the configureComponent method of the class.
private static String	GET Get prefix for properties.
private static String	GET_DATA_STRUCTURE Name of the get data structure method.
private static Method	INVOKE_METHOD Holds a reference to the invoke method of the Invocation class.
private static String	IS Is prefix for boolean properties.
protected ComponentConfiguration	liveConfiguration The component's live configuration
private org.apache.commons.logging.Log	log
protected Interceptor	nextInterceptor Next interceptor in the chain.
private Thread	persistingThread
protected ComponentProxyInvocationHandler	proxyInvocationHandler The invocation handler.
private static String	SET Set prefix for properties.
private static String	SET_NAME Name of the set configuration name method.
protected Component	thisComponent Component being proxied.
private static Collection	UNSUPPORTED_OPERATIONS Holds the list of operations not support by the interceptor.
protected ComponentConfiguration	workingConfiguration The component's working configuration, possibly in an interim/invalid state

Fields inherited from class org.sape.carbon.core.util.reflection.GenericProxy

Constructor Summary

protected

DefaultConfigurationInterceptor(ComponentConfiguration componentConfiguration, ComponentProxyInvocationHandler proxyInvocationHandler, ConfigurationInterceptorConfiguration config) This constructor is protected to allow extension but not direct instantiation.

Method Summary

void	applyConfiguration() Makes the current working configuration live.
private void	configureComponent(ComponentConfiguration newConfiguration) Calls the lifecycle assistant to configure the component.
Class[]	getExposedInterfaces() This implementation returns the ConfigurationInterceptor interface and the component's configuration interface
ComponentConfiguration	getLiveConfiguration() This implementation returns a copy of the component's live configuration.
ComponentConfiguration	getWorkingConfiguration() This implementation returns a copy of the component's working configuration.
protected Object	handleInvoke(Object proxy, Method m, Object[] args) This implementation delegates to: The live configuration object when get methods are invoked on the configuration interface The working configuration object when set methods are invoked on the configuration interface This class for methods called on the ConfigurationInterceptor interface
private void	initializeWorkingConfiguration() This method will create a working configuration if it does not exist
Object	invoke(Invocation invocation) This implementation watches for calls to the configure lifecycle method.
void	nodeChanged(Node changedNode) This implementation causes the component to be reconfigured if the interceptor is configured to auto refresh the component.
void	nodeRemoved(String removedNodeName) This impelementation does nothing when a component's config is removed
void	persistConfiguration() Persists the current live configuration in the Config Service.
void	refreshConfiguration() Same as revertConfiguration, but the configuration node containing this component's configuration is refreshed first.
void	revertConfiguration() Reverts the components live configuration back to its state as of the last call to persistConfiguration or the loading of the component if persistConfiguration was never called.
void	setComponentReference(Component component) Called after creation to pass a reference to the component to each of its decorators.
void	setNextInterceptor(Interceptor interceptor) This method sets the next interceptor as the next in the chain from the current interceptor.

Methods inherited from class org.sape.carbon.core.util.reflection.GenericProxy

invoke, proxyEquals, proxyHashCode, proxyToString

Methods inherited from class java.lang.Object

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

Field Detail

log

private org.apache.commons.logging.Log log

liveConfiguration

protected ComponentConfiguration liveConfiguration

The component's live configuration

workingConfiguration

protected ComponentConfiguration workingConfiguration

The component's working configuration, possibly in an interim/invalid state

proxyInvocationHandler

protected ComponentProxyInvocationHandler proxyInvocationHandler

The invocation handler.

thisComponent

protected Component thisComponent

Component being proxied.

nextInterceptor

protected Interceptor nextInterceptor

Next interceptor in the chain.

persistingThread

private Thread persistingThread

SET

private static final String SET

Set prefix for properties.

See Also:

Constant Field Values

GET

private static final String GET

Get prefix for properties.

See Also:

Constant Field Values

IS

private static final String IS

Is prefix for boolean properties.

See Also:

Constant Field Values

CLONE

private static final String CLONE

Name of the clone method.

See Also:

Constant Field Values

GET_DATA_STRUCTURE

private static final String GET_DATA_STRUCTURE

Name of the get data structure method.

See Also:

Constant Field Values

SET_NAME

private static final String SET_NAME

Name of the set configuration name method.

See Also:

Constant Field Values

UNSUPPORTED_OPERATIONS

private static final Collection UNSUPPORTED_OPERATIONS

Holds the list of operations not support by the interceptor.

CONFIGURE_METHOD

private static final Method CONFIGURE_METHOD

Holds a reference to the configureComponent method of the class.

INVOKE_METHOD

private static final Method INVOKE_METHOD

Holds a reference to the invoke method of the Invocation class.

Constructor Detail

DefaultConfigurationInterceptor

protected DefaultConfigurationInterceptor(ComponentConfiguration componentConfiguration,
                                          ComponentProxyInvocationHandler proxyInvocationHandler,
                                          ConfigurationInterceptorConfiguration config)

This constructor is protected to allow extension but not direct instantiation. Instantiation is handled by the ConfigurationInterceptorFactory in this package.

Parameters:

componentConfiguration - the configuration object this interceptor will manage

proxyInvocationHandler - the proxy invocation handler

Method Detail

getExposedInterfaces

public Class[] getExposedInterfaces()

This implementation returns the ConfigurationInterceptor interface and the component's configuration interface

Specified by:

getExposedInterfaces in interface Decorator

Returns:

Class[] an array of interfaces

setNextInterceptor

public void setNextInterceptor(Interceptor interceptor)

This method sets the next interceptor as the next in the chain from the current interceptor.

Specified by:

setNextInterceptor in interface Interceptor

Parameters:

interceptor - the next interceptor in the chain

setComponentReference

public void setComponentReference(Component component)

Description copied from interface: Decorator

Called after creation to pass a reference to the component to each of its decorators. The component reference should not be used within this method because not all other interceptors have this reference yet and they may rely on this reference thus leading to null pointer exceptions.

Specified by:

setComponentReference in interface Decorator

Parameters:

component - a reference to the component that this interceptor is assisting

See Also:

Decorator.setComponentReference(Component)

persistConfiguration

public void persistConfiguration()
                          throws ConfigurationException

Description copied from interface: ConfigurationInterceptor

Persists the current live configuration in the Config Service.

Specified by:

persistConfiguration in interface ConfigurationInterceptor

Throws:

ConfigurationException - indictes an error persisting the configuration

See Also:

ConfigurationInterceptor.persistConfiguration()

revertConfiguration

public void revertConfiguration()

Description copied from interface: ConfigurationInterceptor

Reverts the components live configuration back to its state as of the last call to persistConfiguration or the loading of the component if persistConfiguration was never called. The working configuration is discarded.

Specified by:

revertConfiguration in interface ConfigurationInterceptor

See Also:

ConfigurationInterceptor.revertConfiguration()

applyConfiguration

public void applyConfiguration()

Description copied from interface: ConfigurationInterceptor

Makes the current working configuration live.

Specified by:

applyConfiguration in interface ConfigurationInterceptor

See Also:

ConfigurationInterceptor.applyConfiguration()

getWorkingConfiguration

public ComponentConfiguration getWorkingConfiguration()

This implementation returns a copy of the component's working configuration. Changes to this object have not effect on the actual working configuration.

Specified by:

getWorkingConfiguration in interface ConfigurationInterceptor

Returns:

ComponentConfiguration the object implementing the component's configuration interface that represents the working copy of the component's configuration

See Also:

ConfigurationInterceptor.getWorkingConfiguration()

getLiveConfiguration

public ComponentConfiguration getLiveConfiguration()

This implementation returns a copy of the component's live configuration. Changes to this object have not effect on the actual live configuration.

Specified by:

getLiveConfiguration in interface ConfigurationInterceptor

Returns:

ComponentConfiguration the object implementing the component's configuration interface that represents the live copy of the component's configuration

See Also:

ConfigurationInterceptor.getWorkingConfiguration()

refreshConfiguration

public void refreshConfiguration()

Description copied from interface: ConfigurationInterceptor

Same as revertConfiguration, but the configuration node containing this component's configuration is refreshed first.

Specified by:

refreshConfiguration in interface ConfigurationInterceptor

See Also:

ConfigurationInterceptor.refreshConfiguration()

invoke

public Object invoke(Invocation invocation)
              throws Throwable

This implementation watches for calls to the configure lifecycle method. When the configure method is called, this method will replace the live configuration with the configuration passed to the configure method. (Should it discard the working copy?)

Specified by:

invoke in interface Interceptor

Parameters:

invocation - the invocation to execute

Returns:

the results of the invocation's execution

Throws:

Throwable - indicates an error with the configruation

nodeChanged

public void nodeChanged(Node changedNode)

This implementation causes the component to be reconfigured if the interceptor is configured to auto refresh the component. This implementation will not refresh the component's configuration if the event is triggered by a call to persistConfiguration because it must already have been applied.

Specified by:

nodeChanged in interface NodeEventListener

Parameters:

changedNode - node that was changed

nodeRemoved

public void nodeRemoved(String removedNodeName)

This impelementation does nothing when a component's config is removed

Specified by:

nodeRemoved in interface NodeEventListener

Parameters:

removedNodeName - name of the removed node

handleInvoke

protected Object handleInvoke(Object proxy,
                              Method m,
                              Object[] args)
                       throws Throwable

This implementation delegates to:

• The live configuration object when get methods are invoked on the configuration interface
• The working configuration object when set methods are invoked on the configuration interface
• This class for methods called on the ConfigurationInterceptor interface

Specified by:

handleInvoke in class GenericProxy

Parameters:

proxy - dynamic proxy

m - method to be invoked

args - the arguments to pass to the method

Returns:

result of the proxied call

Throws:

UnsupportedOperationException - if method getDataStructure, clone, or setName is called

ConfigurationInterceptorException - if the Method m is not assignable from ConfigurationInterceptor or the component's configuration interface

Throwable - indicates a generic error in the invocation chain

initializeWorkingConfiguration

private void initializeWorkingConfiguration()

This method will create a working configuration if it does not exist

configureComponent

private void configureComponent(ComponentConfiguration newConfiguration)

Calls the lifecycle assistant to configure the component.

Parameters:

newConfiguration - the new config to pass to the component