| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.heron.examples.eco; |
| |
| import java.util.Random; |
| |
| public class RandomString { |
| private char[] symbols; |
| |
| private Random random = new Random(); |
| |
| private char[] buf; |
| |
| public RandomString(int length) { |
| // Construct the symbol set |
| StringBuilder tmp = new StringBuilder(); |
| for (char ch = '0'; ch <= '9'; ++ch) { |
| tmp.append(ch); |
| } |
| |
| for (char ch = 'a'; ch <= 'z'; ++ch) { |
| tmp.append(ch); |
| } |
| |
| symbols = tmp.toString().toCharArray(); |
| if (length < 1) { |
| throw new IllegalArgumentException("length < 1: " + length); |
| } |
| |
| buf = new char[length]; |
| } |
| |
| public String nextString() { |
| for (int idx = 0; idx < buf.length; ++idx) { |
| buf[idx] = symbols[random.nextInt(symbols.length)]; |
| } |
| |
| return new String(buf); |
| } |
| } |