org.j3d.util
Class DynamicClassLoader

java.lang.Object
  org.j3d.util.DynamicClassLoader

public class DynamicClassLoader
extends java.lang.Object

A generalised class used to dynamically load other classes according to a preset set of rules.

The class loader uses the CLASSPATH setting to locate and load a given class. If the appropriate methods are called, it will attempt to confirm that the class conforms to a specific interface or base class before actually instantiating that class. Various options are provided for this and the loader automatically checks and issues the appropriate errors.

Internationalisation Resource Names

• nullClassNameMsg: Message when the class name requested to be loaded is null.
• nullBaseClassNameMsg: Message when the base class name requested to be checked against is null
• invalidBaseClassMsg: Message when the loaded class does not implement the requested base class
• nullClassNameMsg: Message when the class failed to initialise

Version:

$Revision: 1.3 $

Author:

Justin Couch

Method Summary

static java.lang.Object	loadBasicClass(java.lang.String name) Load the named class with no checking of the background.
static java.lang.Object	loadCheckedClass(java.lang.String name, java.lang.Class base) Load the class that has the given class as a super class.
static java.lang.Object	loadCheckedClass(java.lang.String name, java.lang.String base) Load the class that has the given class as a super class.

Methods inherited from class java.lang.Object

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

Method Detail

loadBasicClass

public static java.lang.Object loadBasicClass(java.lang.String name)
                                       throws java.lang.ClassNotFoundException,
                                              java.io.InvalidClassException

Load the named class with no checking of the background. The limitation to the loading and instantiation process is that the class must have a public default constructor. As this method does not take any arguments, constructors that do require parameters cannot be called.

Parameters:

name - The fully qualified name of the class to be loaded

Returns:

An instance of the named class if it could be found.

Throws:

java.lang.NullPointerException - The class name supplied is null or zero length

java.lang.ClassNotFoundException - We couldn't locate the class anywhere

java.io.InvalidClassException - The class could not be instantiated either due to internal errors or no default constructor

loadCheckedClass

public static java.lang.Object loadCheckedClass(java.lang.String name,
                                                java.lang.String base)
                                         throws java.lang.ClassNotFoundException,
                                                java.io.InvalidClassException

Load the class that has the given class as a super class. This will check for both the interface and derived class being of the given type.

Parameters:

name - The fully qualified name of the class to be loaded

base - The fully qualified name of the base class to be checked against

Returns:

An instance of the named class if it could be found.

Throws:

java.lang.NullPointerException - The class name or base class name supplied is null or zero length

java.lang.ClassNotFoundException - We couldn't locate the class anywhere

java.io.InvalidClassException - The class could not be instantiated either due to internal errors or no default constructor

loadCheckedClass

public static java.lang.Object loadCheckedClass(java.lang.String name,
                                                java.lang.Class base)
                                         throws java.lang.ClassNotFoundException,
                                                java.io.InvalidClassException

Load the class that has the given class as a super class. This will check for both the interface and derived class being of the given type.

Parameters:

name - The fully qualified name of the class to be loaded

base - The fully qualified name of the base class to be checked against

Returns:

An instance of the named class if it could be found.

Throws:

java.lang.NullPointerException - The class name or base class name supplied is null or zero length

java.lang.ClassNotFoundException - We couldn't locate the class anywhere

java.io.InvalidClassException - The class could not be instantiated either due to internal errors or no default constructor