org.jpu.patterns.factory
Class PropertyFactoryConfigStrategy

java.lang.Object
  org.jpu.patterns.factory.PropertyFactoryConfigStrategy

All Implemented Interfaces:

IPrototypeFactory.IConfigStrategy

public class PropertyFactoryConfigStrategy

extends java.lang.Object

implements IPrototypeFactory.IConfigStrategy

Implementation of IPrototypeFactory.IConfigStrategy for property-file-based configuration. A prototype list should comply with the following syntax:

    <protolist> = [<protospec>{;<protospec>}*]
    <protospec> = [<name1>[,<name2>[,<name3>[,<nameN>]]]=<classname>]
 

where <name1> ... <nameN> are the names under which the prototype is keyed and <classname> is the full name of the prototype implementation class, or of the IPrototypeFactory.IInstantiator to which instantiation should be delegated. Every class listed must have an accessible no-arg constructor.

The source of the <protospec> is by default a System property named "<factoryClassName>.prototypes" where <factoryClassName> is the full class name of the factory being configured; but in the vast majority of cases the subclass will override the following method

 
     protected String fetchPrototypeSpec();
 
 

and have it return the <protospec> from whichever configuration source the application employs.

To specify a delimeter to use instead of ";", override the following method:

 
     protected String getPrototypeDeclarationSeparator();
 
 

Constructor Summary

protected

PropertyFactoryConfigStrategy(IPrototypeFactory fact)

Method Summary

protected java.lang.Object	classNameToInstance(java.lang.String className) Returns a new instance of the prototype whose name is passed.
void	configure()
protected java.lang.String	fetchPrototypeSpec() This method fetches the factory's prototype list from the configuration source.
protected java.lang.String	getAssignmentString() Returns the string that acts as a separator between the list of prototype names and the name of the prototype class.
IPrototypeFactory	getFactory()
protected java.lang.String	getFallbackPrototypeSpec() Returns the prototype spec that is used if none is found in the configuration database.
protected java.lang.String	getPrototypeDeclarationSeparator() Returns the string that acts as a separator between <protospec>'s.
protected java.lang.String	getPrototypeNameSeparator() Returns the string that acts as a separator between successive prototype names.
protected java.lang.String	getPrototypeSpec()
protected boolean	logErrorIfConfigurationUnavailable() Returns whether an error is logged if the default configuration value is unavailable and the fallback is used in its place.
protected void	processOneConfigProtoDef(java.lang.String protoDef) Processes a single prototype declaration.
void	reconfigureIfNecessary()

Methods inherited from class java.lang.Object

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

Constructor Detail

PropertyFactoryConfigStrategy

protected PropertyFactoryConfigStrategy(IPrototypeFactory fact)

Method Detail

getFactory

public IPrototypeFactory getFactory()

Specified by:

getFactory in interface IPrototypeFactory.IConfigStrategy

reconfigureIfNecessary

public void reconfigureIfNecessary()

Specified by:

reconfigureIfNecessary in interface IPrototypeFactory.IConfigStrategy

configure

public void configure()

Specified by:

configure in interface IPrototypeFactory.IConfigStrategy

logErrorIfConfigurationUnavailable

protected boolean logErrorIfConfigurationUnavailable()

Returns whether an error is logged if the default configuration value is unavailable and the fallback is used in its place. Default is true, but subclasses are free to override.

Returns:

true if an error should be logged, false otherwise.

getFallbackPrototypeSpec

protected java.lang.String getFallbackPrototypeSpec()

Returns the prototype spec that is used if none is found in the configuration database. Default is null, but subclasses are free to override.

Returns:

The fallback configuration (null by default).

getPrototypeDeclarationSeparator

protected java.lang.String getPrototypeDeclarationSeparator()

Returns the string that acts as a separator between <protospec>'s. Default is ";", but subclasses are free to override.

getPrototypeNameSeparator

protected java.lang.String getPrototypeNameSeparator()

Returns the string that acts as a separator between successive prototype names. Default is ",", but subclasses are free to override.

getAssignmentString

protected java.lang.String getAssignmentString()

Returns the string that acts as a separator between the list of prototype names and the name of the prototype class. Default is "=", but subclasses are free to override.

processOneConfigProtoDef

protected void processOneConfigProtoDef(java.lang.String protoDef)

Processes a single prototype declaration. Adds prototypes to the factory as necessary.

classNameToInstance

protected java.lang.Object classNameToInstance(java.lang.String className)
                                        throws java.lang.Throwable

Returns a new instance of the prototype whose name is passed. Default implementation is essentially "Thread.currentThread().getContextClassLoader().loadClass(className).newInstance()", but subclasses are free to override.

Throws:

java.lang.Throwable

getPrototypeSpec

protected java.lang.String getPrototypeSpec()

fetchPrototypeSpec

protected java.lang.String fetchPrototypeSpec()

This method fetches the factory's prototype list from the configuration source. The default implementation is as follows:

 
     return System.getProperty( getFactory().getClass().getName() + ".prototypes", "" );
 
 

However, in the majority of cases the subclass will override this to hook into whichever configuration source the application uses.