Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.lang.reflect.ParameterizedType;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Random;

public class Main {
    public static <T> List<T> getRandomCollection(Class<T> collectionType) {
        int collectionSize = new Random().nextInt(10);
        List<T> collection = new ArrayList<T>();
        for (int i = 0; i < collectionSize; i++) {
            Object obj = getRandomValue(collectionType);
            if (obj != null && obj.getClass().isAssignableFrom(collectionType)) {
                collection.add((T) obj);
            }
        }
        return collection;
    }

    private static Object getRandomValue(Class<?> type) {
        if (type.isAssignableFrom(Double.class)) {
            return new Random().nextDouble();
        }
        if (type.isAssignableFrom(Short.class)) {
            return (short) new Random().nextInt();
        }
        if (type.isAssignableFrom(Long.class)) {
            return new Random().nextLong();
        }
        if (type.isAssignableFrom(Integer.class)) {
            return new Random().nextInt();
        }
        if (type.isAssignableFrom(String.class)) {
            return "" + new Random().nextInt();
        }
        if (type.isAssignableFrom(Boolean.class)) {
            return new Random().nextBoolean();
        }
        if (type.isAssignableFrom(Date.class)) {
            return new Date(new Random().nextLong());
        }
        if (type.isAssignableFrom(List.class)) {
            Class<?> listType = (Class<?>) ((ParameterizedType) type.getClass().getGenericSuperclass())
                    .getActualTypeArguments()[0];
            return getRandomCollection(listType);
        }
        return null;
    }
}