* When you sub-class off of BaseEnum, Visual Java will automatically * recognize your type as an enumeration, and offer a choice menu in * the attribute editor of Visual Java for selecting the value of an * attribute of that type. *
* The AlignmentEnum, shown below, is used for setting whether the * text in a Label will appear on the left, center, or right. *
* To use the example below to create a new enumerated type, copy * everything and then modify the imports and static constructor to use * the constants and names for the choices you'd like to offer in your * enumeration. *
* The addConverter call will register your type with Visual Java's * type conversion interface and make it understood that this type is * an enumeration. Change the * "sunsoft.jws.visual.rt.type.AlignmentEnum" argument to reflect the * package name and class of your new enumerated type. * *
* package sunsoft.jws.visual.rt.type;
*
* import sunsoft.jws.visual.rt.type.BaseEnum;
* import sunsoft.jws.visual.rt.type.BaseEnumHelper;
* import sunsoft.jws.visual.rt.type.Converter;
* import java.awt.Label;
*
* public class AlignmentEnum extends BaseEnum {
* private static BaseEnumHelper helper = new BaseEnumHelper();
*
* static {
* helper.add(Label.LEFT, "left");
* helper.add(Label.CENTER, "center");
* helper.add(Label.RIGHT, "right");
* helper.setDefaultChoice(Label.LEFT);
* Converter.addConverter("sunsoft.jws.visual.rt.type.AlignmentEnum",
* "sunsoft.jws.visual.rt.type.BaseEnumConverter");
* }
*
* public AlignmentEnum() {
* super();
* }
*
* public AlignmentEnum(int choice) {
* super(choice);
* }
*
* public AlignmentEnum(String choice) {
* super(choice);
* }
*
* protected BaseEnumHelper getHelper() {
* return(helper);
* }
* }
*
*
* @see BaseEnumHelper
* @see AlignmentEnum
* @see java.awt.Label
* @version 1.17, 07/25/97
*/
/* END JSTYLED */
public abstract class BaseEnum implements Cloneable {
/**
* The currently selected value from the enum.
*/
protected Integer currentChoice;
/**
* Constructor, sets the choice to the default.
*/
protected BaseEnum() {
set(getHelper().getDefaultChoice());
}
/**
* Constructor to use when integer value is available.
*
* @param choice enumerated value
*/
protected BaseEnum(int choice) {
set(choice);
}
/**
* Constructor to use when string of choice is available.
*
* @param choice enumerated value
*/
protected BaseEnum(String choice) {
set(choice);
}
/**
* Gets the helper class that stores the enum definition.
*
* Each sub-classer should override this so that a different
* class-wide instance of BaseEnumHelper is returned. If there
* weren't a mechanism like this, then all sub-classers would be
* sharing a single helper, and that would be bad.
*
* @return a helper use by all enumeration instances of
* a single class
*/
protected abstract BaseEnumHelper getHelper();
/**
* Sets the enumeration to the given integer value.
* Checks validity
* of the choice.
*
* @param choice enumerated value
* @exception Error when an invalid choice is given
*/
public void set(int choice) {
if (getHelper().isValid(choice))
currentChoice = new Integer(choice);
else
throw new ParseException(Global.fmtMsg(
"sunsoft.jws.visual.rt.type.BaseEnum.FMT.30",
Global.getMsg(
"sunsoft.jws.visual.rt.type.BaseEnum.invalid__int__choice__"),
new Integer(choice),
/* BEGIN JSTYLED */
Global.getMsg("sunsoft.jws.visual.rt.type.BaseEnum.__given__to__Enum__class.14")));
/* END JSTYLED */
}
/**
* Sets the enumeration to the given string value. Checks validity
* of the choice.
*
* @param choice string version of the enumerated value
* @exception Error when an invalid choice is given
*/
public void set(String choice) {
if (getHelper().isValid(choice))
currentChoice = getHelper().getInteger(choice);
else
throw new ParseException(Global.fmtMsg(
"sunsoft.jws.visual.rt.type.BaseEnum.FMT.30",
/* BEGIN JSTYLED */
Global.getMsg("sunsoft.jws.visual.rt.type.BaseEnum.invalid__string__choic.15"),
choice,
Global.getMsg("sunsoft.jws.visual.rt.type.BaseEnum.__given__to__Enum__class.16")));
/* END JSTYLED */
}
/**
* Returns the int value of the current selection
* from the enumeration.
*/
public int intValue() {
return (currentChoice.intValue());
}
/**
* Returns the String description of the current selection from the
* enumeration.
*/
public String toString() {
return (getHelper().getString(currentChoice));
}
/**
* Returns a java.util.Enumeration of the String descriptions
* available in this enum.
*/
public Enumeration elements() {
return (getHelper().elements());
}
/**
* Returns an array containing all of the String descriptions
* available in this enum.
*/
public String[] descriptions() {
return (getHelper().descriptions());
}
/**
* Returns a copy of this enumeration instance.
*/
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError();
}
}
/**
* Returns true if this enumeration instance and the one given have
* the same selection made.
*/
public boolean equals(Object obj) {
if (obj instanceof BaseEnum) {
if (getClass() == obj.getClass()) {
Integer otherChoice = ((BaseEnum)obj).currentChoice;
if (currentChoice != null)
return (currentChoice.equals(otherChoice));
else
return (otherChoice == null);
}
}
return false;
}
}