Traverse collection - Android java.util

Android examples for java.util:Collection

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Description

Traverse collection

Demo Code

/*//from   ww  w .jav  a 2  s.  c o  m
 * 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.
 */
//package com.java2s;

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);
    }
}

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