I have a class declaring constants for my app
public class GroupConstants {
..
public static final int INTEGER_VALUE = 1;
public static final int LONG_VALUE = 2;
public static final int STRING_VALUE = 3;
..
}
In the code there is a set of switch statements
private static Object getValue(String stringValue, Parameter parameter) throws InvalidPatternException
{
Object result=null;
switch (parameter.getDataType())
{
case GroupConstants.STRING_VALUE: // String value
result=stringValue;
break;
case GroupConstants.INTEGER_VALUE: // Long value
case GroupConstants.LONG_VALUE:
case GroupConstants.BOOLEAN_VALUE:
case GroupConstants.DATE_VALUE:
..
}
I want to refactor the int constant values to be represented by an enum
public enum DataType {
UNKNOWN_VALUE(0,"unknown"),
INTEGER_VALUE(1,"integer"),
LONG_VALUE(2,"long"),
STRING_VALUE(3,"string"),
BOOLEAN_VALUE(4,"boolean"),
..
}
so my code might look like this
@Deprecated
public static final int INTEGER_VALUE = DataType.INTEGER_VALUE.getId();
and overtime i can change my switch statements. When i change the static final int reference to point to the enum all my switch statements break.
[javac] /home/assure/projects/tp/main/src/a/b/c/DDDDDManagerBean.java:1108: constant expression required
[javac] case GroupConstants.INTEGER_VALUE:
[javac] ^
[javac] /home/assure/projects/tp/main/src/a/b/c/ParameterComponent.java:203: constant expression required
[javac] case GroupConstants.INTEGER_VALUE:
[javac] ^
[javac] /home/assure/projects/tp/main/src/a/b/c/ParameterComponent.java:268: constant expression required
[javac] case GroupConstants.INTEGER_VALUE:
[javac] ^
[javac] /home/assure/projects/tp/main/src/a/b/c/ParameterComponent.java:316: constant expression required
[javac] case GroupConstants.INTEGER_VALUE:
[javac] ^
[javac] /home/assure/projects/tp/main/src/a/b/c/ParameterComponent.java:436: constant expression required
[javac] case GroupConstants.INTEGER_VALUE:
I don't want to be forced to change all the switches yet, so its there a clean work around?
Best Answer
Java has native support of enums in switch statements. In your case you should say: