Java Class New Instance newInstance(String clazz)

Description

new Instance

License

Open Source License

Declaration

public static Object newInstance(String clazz) 

Method Source Code

//package com.java2s;
/**/*from  ww  w . ja v a 2 s. c  o m*/
 *     Copyright (C) 2013-2014  the original author or authors.
 *
 *     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,
 *     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/>
 */

import java.lang.reflect.Constructor;

import com.google.common.base.Strings;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

public class Main {
    public static Object newInstance(String clazz) {
        checkState(!Strings.isNullOrEmpty(clazz));

        try {
            return Class.forName(clazz).newInstance();
        } catch (Exception exception) {
            throw new RuntimeException(exception);
        }
    }

    public static Object newInstance(final String clazzName, final Object... params) {
        try {
            Constructor<?> method = Class.forName(clazzName).getDeclaredConstructor(getArgsType(params));
            checkNotNull(method).setAccessible(true);
            return method.newInstance(params);
        } catch (Exception exception) {
            throw new RuntimeException("Error in create instance of class " + clazzName);
        }
    }

    /**
     * @param params
     * @return
     */
    private static Class<?>[] getArgsType(Object... params) {
        Class<?>[] paramsTypes = null;
        if (params != null && params.length > 0) {
            paramsTypes = new Class[params.length];
            for (int i = 0; i < params.length; i++) {
                Class<?> superClassType = params[i].getClass().getSuperclass();
                if (superClassType != null && !superClassType.equals(Object.class)) {
                    paramsTypes[i] = superClassType;
                } else {
                    paramsTypes[i] = params[i].getClass();
                }
            }
        }
        return paramsTypes;
    }
}

Related

1. newInstance(String className, Object... params)
2. newInstance(String className, Object[] args)
3. newInstance(String className, Object[] args)
4. newInstance(String className, Object[] args)
5. newInstance(String classname, Properties properties)
6. newInstance(String clazzStr)
7. newInstance(String cls, Class interfaceType)
8. newInstance(String klass)
9. newInstance(String name)