Java tutorial
//package com.java2s; /* * Copyright (C) 2016 venshine.cn@gmail.com * * 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.util.Collection; public class Main { private static final String DELIMITER = ","; /** * Traverse collection * * @param c * @param <T> * @return */ public static <T> String traverseCollection(Collection<T> c) { if (!isEmpty(c)) { int len = c.size(); StringBuilder builder = new StringBuilder(len); int i = 0; for (T t : c) { if (t == null) { continue; } builder.append(t.toString()); i++; if (i < len) { builder.append(DELIMITER); } } return builder.toString(); } return null; } /** * Judge whether a collection is null or size is 0 * * @param c * @param <V> * @return */ public static <V> boolean isEmpty(Collection<V> c) { return (c == null || c.size() == 0); } }