/**
* 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());
}
}
}