Utils.java

/*
 * Vitry, copyright (C) Hans Hoglund 2011
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See COPYING.txt for details.
 */
package vitry.runtime.util;

import java.lang.reflect.Constructor;


public class Utils
{
    private Utils() {
    }

    public static Constructor<?> getConstructor(Class<?> klass, Class<?>... parameterTypes)
            throws NoSuchMethodException, SecurityException
    {
        Constructor<?>[] constructors = klass.getConstructors();
        SEARCH : for (Constructor<?> c : constructors)
        {
            Class<?>[] constructorParameterTypes = c.getParameterTypes();

            if (constructorParameterTypes.length != parameterTypes.length)
                continue SEARCH;

            for (int i = 0; i < parameterTypes.length; i++)
            {
                if (!constructorParameterTypes[i].isAssignableFrom(parameterTypes[i]))
                    continue SEARCH;
            }
            return c;
        }
        throw new NoSuchMethodException(klass.getName() + ".<init>"
                + argumentTypesToString(parameterTypes));
    }

    private static String argumentTypesToString(Class<?>[] argTypes)
    {
        StringBuilder buf = new StringBuilder();
        buf.append("(");
        if (argTypes != null)
        {
            for (int i = 0; i < argTypes.length; i++)
            {
                if (i > 0)
                {
                    buf.append(", ");
                }
                Class<?> c = argTypes[i];
                buf.append( (c == null) ? "null" : c.getName());
            }
        }
        buf.append(")");
        return buf.toString();
    }


    public static <U> U unsafe(Object val)
    {
        @SuppressWarnings("unchecked")
        U casted = (U) val;
        return casted;
    }

    public static <T> void nothing(T val)
    {
        return;
    }

    public static <T> T assertFalse()
    {
        return Utils.<T> assertFalse("");
    }

    public static <T> T assertFalse(String msg)
    {
        throw new AssertionError(msg);
    }


    public static int hash(int seed, int val)
    {
        return (seed * 65050 + val) % 2044508069;
    }

    public static int hash(int seed, Object val)
    {
        return hash(seed, val.hashCode());
    }

    public static int hash(int seed, Iterable<?> vals)
    {
        int hash = seed;
        for (Object v : vals)
            hash = hash(hash, v);
        return hash;
    }

}