Modifier.PUBLIC | Modifier.PRIVATE | Modifier.PROTECTED : Constructor « Reflection « Java Tutorial

1. Java Tutorial
2. Reflection
3. Constructor

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import static java.lang.System.out;

import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;

public class ConstructorAccess {
  public static void main(String... args) {
    try {
      Class<?> c = Class.forName(args[0]);
      Constructor[] allConstructors = c.getDeclaredConstructors();
      for (Constructor ctor : allConstructors) {
        int searchMod = modifierFromString(args[1]);
        int mods = accessModifiers(ctor.getModifiers());
        if (searchMod == mods) {
          out.format("%s%n", ctor.toGenericString());
          out.format("  [ synthetic=%-5b var_args=%-5b ]%n",
              ctor.isSynthetic(), ctor.isVarArgs());
        }
      }

      // production code should handle this exception more gracefully
    } catch (ClassNotFoundException x) {
      x.printStackTrace();
    }
  }

  private static int accessModifiers(int m) {
    return m & (Modifier.PUBLIC | Modifier.PRIVATE | Modifier.PROTECTED);
  }

  private static int modifierFromString(String s) {
    if ("public".equals(s))
      return Modifier.PUBLIC;
    else if ("protected".equals(s))
      return Modifier.PROTECTED;
    else if ("private".equals(s))
      return Modifier.PRIVATE;
    else if ("package-private".equals(s))
      return 0;
    else
      return -1;
  }
}