Java tutorial
/* * Licensed to the Ted Dunning under one or more contributor license * agreements. See the NOTICE file that may be * distributed with this work for additional information * regarding copyright ownership. Ted Dunning 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 com.mapr.synth.samplers; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.node.TextNode; import java.util.Random; /** * Samples a version 4 (random) UUID. Note that the random bits generated are pull from the * standard Java random number generator and are subject to limitations because of that. * * See http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29 * * Thread safe. */ public class UUIDSampler extends FieldSampler { private Random rand = new Random(); public UUIDSampler() { } public void setSeed(long seed) { rand.setSeed(seed); } @Override public JsonNode sample() { int a = rand.nextInt(); int b = rand.nextInt(1 << 16); int c = 0x4000 + rand.nextInt(1 << 12); int d = 0x8000 + rand.nextInt(1 << 14); long e = rand.nextLong() & ((1L << 48) - 1); return new TextNode(String.format("%08x-%04x-%04x-%04x-%012x", a, b, c, d, e)); } }