util
Class CreateClass

java.lang.Object
  util.CreateClass

All Implemented Interfaces:

Cloneable

public class CreateClass
extends Object
implements Cloneable

This is a try to allow dynamic creation of classes without methods using a description. This is only a very crude work-around and not really a dynamical class definition. The other way, writing a ClassLoader appears to be too sophisticated for this simple task. Still, remeber that using this interface may not be the fastest choice, since it completely relies on standard java methods, like Hashtable and the Wrapper classes for the prmitive data types.

Field Summary

private static Class	KEY
private static String[]	NAME
private Hashtable<String,Class>	Names
private static Class	NUMBER
private static char[]	SHORT
private static Class[]	TYPE
private Hashtable<String,Object>	Values

Constructor Summary

private

CreateClass(int size)

Method Summary

void	clearField(String name) Removes the definition of the field with the given name.
Object	clone() Clone this instance of CreateClass.
private boolean	compareHashtable(Hashtable one, Hashtable two) Check, if keys/values in the two Hashtables match.
boolean	equals(Object that) Test for equal CreateClass objects.
boolean	equalType(Object that) Test for equal type of CreateClass objects.
Enumeration	getAllNames() Returns an Enumeration of all fields found in this CreateClass.
Object	getField(String name) This method retrieves values by field names.
static CreateClass	getInstance(String[] name, char[] type) This method retrives a new Instance of createClass.
static CreateClass	getInstance(String[] name, Class[] type) This method retrives a new Instance of createClass.
static CreateClass	getInstance(String[] name, String[] type) This method retrives a new Instance of createClass.
Enumeration	getNames() Returns an Enumeration of all fields assigned a value.
Class	getType(String name) This method retrieves the prototype class of the field with the given name.
void	loadField(String name, String value) This method assigns a value to a named field.
String	toString() Returns a String representation of this CreateClass.

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

KEY

private static Class KEY

NUMBER

private static Class NUMBER

SHORT

private static final char[] SHORT

NAME

private static final String[] NAME

TYPE

private static Class[] TYPE

Names

private Hashtable<String,Class> Names

Values

private Hashtable<String,Object> Values

Constructor Detail

CreateClass

private CreateClass(int size)

Method Detail

getInstance

public static CreateClass getInstance(String[] name,
                                      char[] type)

This method retrives a new Instance of createClass. Class variables, if you want to call them this way, can be retrieved with getField(name). This method uses the short, though slower routine of providing short (one char) identifiers for the java native Wrapper classes.
Valid appreviations for the native types are:

• b for Boolean
• B for Byte
• s for Short
• i for Integer
• l for Long
• f for Float
• d for Double
• S for String

See Also:

loadField(java.lang.String, java.lang.String), getField(java.lang.String)

getInstance

public static CreateClass getInstance(String[] name,
                                      String[] type)

This method retrives a new Instance of createClass. Class variables, if you want to call them this way, can be retrieved with getField(name). This method uses the names for the java native Wrapper classes.

getInstance

public static CreateClass getInstance(String[] name,
                                      Class[] type)

This method retrives a new Instance of createClass. Class variables, if you want to call them this way, can be retrieved with getField(name). Note that we only create the Classes, but do not assign a value to the fields here.

See Also:

loadField(java.lang.String, java.lang.String), getField(java.lang.String)

clone

public Object clone()

Clone this instance of CreateClass. It returns a shallow copy of this creatClass in the sense that the Names Hashtable is cloned (which is already a shallow copy), but the Values Hashtable is empty. This clone method differs somehow from the original purpose since it calls the constructor of CreateClass.

Overrides:

clone in class Object

See Also:

Hashtable.clone()

clearField

public void clearField(String name)

Removes the definition of the field with the given name. If no value is asigned to the field, nothing happens. Subsequent calls to getField return null.

Parameters:

name - The field to unset.

See Also:

Hashtable.remove(java.lang.Object)

loadField

public void loadField(String name,
                      String value)

This method assigns a value to a named field. All primitive data types understand a constructor with a single String argument, so this is how we assign the value to it. If you ever try to expand the class for some peculiar, user-defined classes, make sure that they can be constructed with a single String!

Parameters:

name - The field name

value - The value that should be assigned to the field

getField

public Object getField(String name)

This method retrieves values by field names. You get an Object, for primitive data types a wrapper, which can be cast directly to the appropriate type. If the calling class is only interested in the type of field, use the method fieldType instead.

Parameters:

name - The name of the field to retrieve.

See Also:

getType(java.lang.String)

getType

public Class getType(String name)

This method retrieves the prototype class of the field with the given name. Use this, if you are interested only in the type of the field, but not it's value.

Parameters:

name - The name of the field to retrieve.

See Also:

getField(java.lang.String)

getNames

public Enumeration getNames()

Returns an Enumeration of all fields assigned a value. Uses the Hashtable.keys() function of the values to retrieve an Enumeration of all fields in this class that have a value assigned to it.

getAllNames

public Enumeration getAllNames()

Returns an Enumeration of all fields found in this CreateClass. Uses the Hashtable.keys() function of the Names to retrieve an Enumeration of all fields in this class that are ready to take a value.

compareHashtable

private boolean compareHashtable(Hashtable one,
                                 Hashtable two)

Check, if keys/values in the two Hashtables match.

equalType

public boolean equalType(Object that)

Test for equal type of CreateClass objects. Comparison is done by checking and comparing the entries in the Names Hashtable.

Parameters:

that - The CreateClass instance to be compared to.

equals

public boolean equals(Object that)

Test for equal CreateClass objects. Additionally to a equalType-check, all the fields in the Values Hashtable are compared. Note that this method will return false, if either of the Values Hashtable is null.

Overrides:

equals in class Object

Parameters:

that - The CreateClass instance to be compared to.

toString

public String toString()

Returns a String representation of this CreateClass. In this one-line String, every Value entry is listed as the key name plus its value. Key/value pairs are separated by an equal sign, the different pairs are separated by a space.

Overrides:

toString in class Object