constructoraccess.java

来自「it contains the practical programs in ou」· Java 代码 · 共 39 行

import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import static java.lang.System.out;

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;
    }
}