Get and set value of a Enum type field : Enum « Reflection « Java

1. Java
2. Reflection
3. Enum

Get and set value of a Enum type field

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 *
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import static java.lang.System.out;

import java.lang.reflect.Field;

enum TraceLevel {
  OFF, LOW, MEDIUM, HIGH, DEBUG
}

class MyServer {
  private TraceLevel level = TraceLevel.OFF;
}

public class SetTrace {
  public static void main(String... args) {
    TraceLevel newLevel = TraceLevel.valueOf(args[0]);

    try {
      MyServer svr = new MyServer();
      Class<?> c = svr.getClass();
      Field f = c.getDeclaredField("level");
      f.setAccessible(true);
      TraceLevel oldLevel = (TraceLevel) f.get(svr);
      out.format("Original trace level:  %s%n", oldLevel);

      if (oldLevel != newLevel) {
        f.set(svr, newLevel);
        out.format("    New  trace level:  %s%n", f.get(svr));
      }

      // production code should handle these exceptions more gracefully
    } catch (IllegalArgumentException x) {
      x.printStackTrace();
    } catch (IllegalAccessException x) {
      x.printStackTrace();
    } catch (NoSuchFieldException x) {
      x.printStackTrace();
    }
  }
}

 

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