Get modifiers for constructors in Java

Description

The following code shows how to get modifiers for constructors.

Example


/*ww  w . j  a  va  2  s  . co m*/
import static java.lang.System.out;

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

public class Main {
  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;
  }
}
/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

The code above generates the following result.





















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