Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.Collection;
import java.util.Collections;

import java.util.HashSet;

import java.util.Set;

public class Main {
    /**
     * Returns a collection with the common elements in c1 and c2
     * @param <T>
     * @param c1
     * @param c2
     * @return
     */
    public static <T> Collection<T> intersect(Collection<T> c1, Collection<T> c2) {

        if (c1.isEmpty() || c2.isEmpty()) {
            return Collections.emptySet();
        }

        if (!(c2 instanceof Set) && (c1 instanceof Set || c1.size() > c2.size())) {
            //swap
            Collection<T> tmp = c1;
            c1 = c2;
            c2 = tmp;
        }

        Collection<T> result = new HashSet<T>();
        for (T obj : c1) {
            if (c2.contains(obj)) {
                result.add(obj);
            }
        }

        return result;
    }
}