/** * Copyright (c) 2010 Yahoo! Inc. All rights reserved. * * 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. See accompanying * LICENSE file. */ package com.couchbase.loadgen.generator; /** * Generate a popularity distribution of items, skewed to favor recent items * significantly more than older items. */ public class SkewedLatestGenerator extends IntegerGenerator { CounterGenerator _basis; ZipfianGenerator _zipfian; public SkewedLatestGenerator(CounterGenerator basis) { _basis = basis; _zipfian = new ZipfianGenerator(Integer.parseInt(_basis.lastString())); nextInt(); } /** * Generate the next string in the distribution, skewed Zipfian favoring the * items most recently returned by the basis generator. */ public int nextInt() { int max = Integer.parseInt(_basis.lastString()); int nextint = max - _zipfian.nextInt(max); setLastInt(nextint); return nextint; } public static void main(String[] args) { SkewedLatestGenerator gen = new SkewedLatestGenerator( new CounterGenerator(1000)); for (int i = 0; i < Integer.parseInt(args[0]); i++) { System.out.println(gen.nextString()); } } }