Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright 2014 Andrew Reitz
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

public class Main {
    /**
     * Takes a class type and constructs it. If the class does not have an empty constructor this
     * will
     * find the parametrized constructor and use nulls and default values to construct the class.
     *
     * @param clazz The class to construct.
     * @param <T> The type of the class to construct.
     * @return The constructed object.
     */
    public static <T> T createInstance(Class<T> clazz) {
        T created = null;
        Constructor<?>[] constructors = clazz.getConstructors();
        for (Constructor<?> constructor : constructors) {
            if (!Modifier.isPrivate(constructor.getModifiers())) {
                Class<?>[] parameterTypes = constructor.getParameterTypes();
                List<Object> params = new ArrayList<Object>();
                for (Class<?> parameterType : parameterTypes)
                    if (!parameterType.isPrimitive()) {
                        params.add(null);
                    } else {
                        if (parameterType == boolean.class) {
                            params.add(false);
                        } else {
                            params.add(0);
                        }
                    }

                try {
                    @SuppressWarnings("unchecked")
                    T newObject = (T) constructor.newInstance(params.toArray());
                    created = newObject;
                } catch (InvocationTargetException e) {
                    throw new RuntimeException(e);
                } catch (InstantiationException e) {
                    throw new RuntimeException(e);
                } catch (IllegalAccessException e) {
                    throw new RuntimeException(e);
                }
                break;
            }
        }
        return created;
    }
}