edu.rit.util

Class Instance

java.lang.Object

edu.rit.util.Instance

public class Instance
extends java.lang.Object

Class Instance provides static methods for creating instances of classes.

Method Summary

Modifier and Type	Method and Description
static java.lang.Object	newInstance(java.lang.String s) Create a new instance of a class as specified by the given string.

Methods inherited from class java.lang.Object

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

Method Detail

newInstance

public static java.lang.Object newInstance(java.lang.String s)
                                    throws java.lang.ClassNotFoundException,
                                           java.lang.NoSuchMethodException,
                                           java.lang.InstantiationException,
                                           java.lang.IllegalAccessException,
                                           java.lang.reflect.InvocationTargetException

Create a new instance of a class as specified by the given string. The string must consist of a fully-qualified class name, a left parenthesis, zero or more comma-separated arguments, and a right parenthesis. No whitespace is allowed. This method attempts to find a constructor for the given class as follows, where N is the number of arguments:

• If N = 0, use a no-argument constructor.

• Else if all arguments are integers, use a constructor with N arguments of type int.

• Else if all arguments are integers and there is no such constructor, use a constructor with one argument of type int[].

• Else if not all arguments are integers, use a constructor with N arguments of type String.

• Else if not all arguments are integers and there is no such constructor, use a constructor with one argument of type String[].

• Else throw a NoSuchMethodException.

This method invokes the chosen constructor, passing in the given argument values, and returns a reference to the newly-created instance.

Note: To find the given class, the calling thread's context class loader is used.

Parameters:

s - Constructor expression string.

Returns:

New instance.

Throws:

java.lang.IllegalArgumentException - (unchecked exception) Thrown if s does not obey the required syntax.

java.lang.ClassNotFoundException - Thrown if the given class cannot be found.

java.lang.NoSuchMethodException - Thrown if a suitable constructor cannot be found in the given class.

java.lang.InstantiationException - Thrown if an instance cannot be created because the given class is an interface or an abstract class.

java.lang.IllegalAccessException - Thrown if an instance cannot be created because the calling method does not have access to the given constructor.

java.lang.reflect.InvocationTargetException - Thrown if the given constructor throws an exception.