net.smartlab.config
Class Configuration

java.lang.Object
  net.smartlab.config.Element
      net.smartlab.config.Node
          net.smartlab.config.Configuration

Direct Known Subclasses:

SQLConfiguration, XMLConfiguration

public abstract class Configuration
extends Node

This class provides a skeletal implementation of a configuration tree to provide a set of common operations with a generic implementation.

Author:

rlogiacco

Field Summary

protected java.util.Collection	listeners
protected net.smartlab.config.Configuration.Monitor	monitor

Fields inherited from class net.smartlab.config.Node

attributes, children, content, resolved

Fields inherited from class net.smartlab.config.Element

name, parent

Constructor Summary

protected

Configuration() Creates an instance of the class as an Element without a parent node.

Method Summary

void	addListener(Listener listener) Adds a configuration changes listener.
protected void	check() Checks if the underling configuration has been changed and notifies listeners of the change.
static Configuration	getInstance(java.lang.String uri) Returns an instance of a Configuration subclass accordingly to the provided URI.
static Configuration	getInstance(java.lang.String uri, java.util.Collection listeners) Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided collection of listeners.
static Configuration	getInstance(java.lang.String uri, Listener listener) Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided listener.
static Configuration	getInstance(java.net.URI uri) Returns an instance of a Configuration subclass accordingly to the provided URI.
static Configuration	getInstance(java.net.URI uri, java.util.Collection listeners) Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided collection of listeners.
static Configuration	getInstance(java.net.URI uri, Listener listener) Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided listener.
java.util.Collection	getListeners() Returns the registered changes listeners.
boolean	getResolve() Returns the resolution method adopted by this configuration tree.
protected void	init(java.lang.String name, org.xml.sax.Attributes attributes) Initializes this configuration with a name and a set of attributes.
abstract boolean	isChanged() This method checks if the source from the configuration structure was modified since it was last read.
void	removeListener(Listener listener) Removes a configuration changes listener.
protected Node	resolve(java.lang.String name, java.lang.String id) Resolves the requested reference through its children nodes or, recursively in the parent node children.
void	setResolve(boolean resolve) Sets the resolution method to adopt while querying this configuration tree.
abstract void	update() Ensures the in memory representation of the configuration matches with the underlying representation.

Methods inherited from class net.smartlab.config.Node

getAttribute, getAttributeNames, getAttributes, getContent, getElement, getElements, getElements, getId, resolve, setContent

Methods inherited from class net.smartlab.config.Element

getAttributeValues, getElement, getElement, getName, toString

Methods inherited from class java.lang.Object

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

Field Detail

listeners

protected java.util.Collection listeners

monitor

protected net.smartlab.config.Configuration.Monitor monitor

Constructor Detail

Configuration

protected Configuration()

Creates an instance of the class as an Element without a parent node. This constructor is providen for subclasses convenience.

Method Detail

init

protected void init(java.lang.String name,
                    org.xml.sax.Attributes attributes)

Initializes this configuration with a name and a set of attributes.

Parameters:

name - the name of the configuration tree.

attributes - a set of attributes relative to the global configuration tree.

resolve

protected Node resolve(java.lang.String name,
                       java.lang.String id)
                throws ConfigurationException

Description copied from class: Node

Resolves the requested reference through its children nodes or, recursively in the parent node children.

Overrides:

resolve in class Node

Parameters:

name - the referenced element name.

id - the referenced element identifier.

Returns:

the referenced element.

Throws:

ConfigurationException - if the referenced element cannot be found in the wntire configuration tree.

See Also:

Node.resolve(java.lang.String, java.lang.String)

isChanged

public abstract boolean isChanged()
                           throws ConfigurationException

This method checks if the source from the configuration structure was modified since it was last read.

Returns:

true if the underlying representation of the structure was modified since last read.

Throws:

ConfigurationException - if something wrong occurred while checking the underlaying structure like the file is no more readable or the stream no more available.

update

public abstract void update()
                     throws ConfigurationException

Ensures the in memory representation of the configuration matches with the underlying representation.

Throws:

ConfigurationException - if the underlying representation of the structure is no more accessible or the decoding process fails due to an unappropriately initialized Cipher.

setResolve

public void setResolve(boolean resolve)

Sets the resolution method to adopt while querying this configuration tree. When set to true all internal references are automatically resolved to the destination node if present in the configuration tree.

Parameters:

resolve - the resolution method to adopt.

getResolve

public boolean getResolve()

Returns the resolution method adopted by this configuration tree.

Returns:

true if internal references should be automatically resolved.

getListeners

public java.util.Collection getListeners()

Returns the registered changes listeners.

Returns:

the registered changes listeners.

addListener

public void addListener(Listener listener)

Adds a configuration changes listener.

Parameters:

listener - the listener to add.

removeListener

public void removeListener(Listener listener)

Removes a configuration changes listener.

Parameters:

listener - the listener to remove.

getInstance

public static final Configuration getInstance(java.lang.String uri)
                                       throws ConfigurationException,
                                              java.net.URISyntaxException

Returns an instance of a Configuration subclass accordingly to the provided URI. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

java.net.URISyntaxException

getInstance

public static final Configuration getInstance(java.lang.String uri,
                                              Listener listener)
                                       throws ConfigurationException,
                                              java.net.URISyntaxException

Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided listener. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

listener - a Listener interface implementation.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

java.net.URISyntaxException

getInstance

public static final Configuration getInstance(java.lang.String uri,
                                              java.util.Collection listeners)
                                       throws ConfigurationException,
                                              java.net.URISyntaxException

Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided collection of listeners. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

listeners - a collection of Listener interface implementors.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

java.net.URISyntaxException

getInstance

public static final Configuration getInstance(java.net.URI uri)
                                       throws ConfigurationException

Returns an instance of a Configuration subclass accordingly to the provided URI. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

getInstance

public static final Configuration getInstance(java.net.URI uri,
                                              Listener listener)
                                       throws ConfigurationException

Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided listener. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

listener - a Listener interface implementation.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

getInstance

public static final Configuration getInstance(java.net.URI uri,
                                              java.util.Collection listeners)
                                       throws ConfigurationException

Returns an instance of a Configuration subclass accordingly to the provided URI monitoring it for updates which will be notified to the provided collection of listeners. Monitoring interval can be set through the system property smartconfig.monitor.delay expressed in milliseconds and defaulting to 60000.

Parameters:

uri - the URI to access the configuration.

listeners - a collection of Listener interface implementors.

Returns:

an instance of a Configuration subclass.

Throws:

ConfigurationException - if no handler matches the specified URI or an error is encountered trying to access the configuration URI.

check

protected final void check()

Checks if the underling configuration has been changed and notifies listeners of the change.