Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.Collection;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

public class Main {
    public static <T> Set<T> union(Set<T> set1, Set<T> set2) {
        if (isEmpty(set1)) {
            return set2;
        }
        if (isEmpty(set2)) {
            return set1;
        }

        Set<T> result = createHashSet(set1);
        result.addAll(set2);
        return result;
    }

    public static boolean isEmpty(Map<?, ?> map) {
        return (map == null) || (map.size() == 0);
    }

    public static boolean isEmpty(Collection<?> collection) {
        return (collection == null) || (collection.size() == 0);
    }

    public static <E> HashSet<E> createHashSet() {
        return new HashSet<E>();
    }

    public static <E> HashSet<E> createHashSet(int initialCapacity) {
        return new HashSet<E>(initialCapacity);
    }

    public static <E> HashSet<E> createHashSet(Collection<? extends E> collection) {
        if (collection == null) {
            return new HashSet<E>();
        }
        return new HashSet<E>(collection);
    }

    public static <E, O extends E> HashSet<E> createHashSet(O... args) {
        if (args == null || args.length == 0) {
            return new HashSet<E>();
        }

        HashSet<E> set = new HashSet<E>(args.length);
        for (O o : args) {
            set.add(o);
        }

        return set;
    }

    public static <T> HashSet<T> createHashSet(Iterable<? extends T> iter) {
        HashSet<T> set;

        if (iter instanceof Collection<?>) {
            set = new HashSet<T>((Collection<? extends T>) iter);
        } else {
            set = new HashSet<T>();
            iterableToCollection(iter, set);
        }

        return set;
    }

    private static <E> void iterableToCollection(Iterable<? extends E> iter, Collection<E> list) {
        if (iter == null) {
            return;
        }

        for (E element : iter) {
            list.add(element);
        }
    }
}