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/*
* Copyright (C) 2010 The Guava Authors
*
* 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.google.common.collect;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.primitives.Ints;
import java.util.Collections;
import java.util.List;
import java.util.Set;
/**
* Package up sample data for common collections benchmarking.
*
* @author Nicholaus Shupe
*/
class CollectionBenchmarkSampleData {
private final boolean isUserTypeFast;
private final SpecialRandom random;
private final double hitRate;
private final int size;
private final Set<Element> valuesInSet;
private final Element[] queries;
CollectionBenchmarkSampleData(int size) {
this(true, new SpecialRandom(), 1.0, size);
}
CollectionBenchmarkSampleData(
boolean isUserTypeFast,
SpecialRandom random,
double hitRate,
int size) {
this.isUserTypeFast = isUserTypeFast;
this.random = checkNotNull(random);
this.hitRate = hitRate;
this.size = size;
this.valuesInSet = createData();
this.queries = createQueries(valuesInSet, 1024);
}
Set<Element> getValuesInSet() {
return valuesInSet;
}
Element[] getQueries() {
return queries;
}
private Element[] createQueries(Set<Element> elementsInSet, int numQueries) {
List<Element> queryList = Lists.newArrayListWithCapacity(numQueries);
int numGoodQueries = (int) (numQueries * hitRate + 0.5);
// add good queries
int size = elementsInSet.size();
if (size > 0) {
int minCopiesOfEachGoodQuery = numGoodQueries / size;
int extras = numGoodQueries % size;
for (int i = 0; i < minCopiesOfEachGoodQuery; i++) {
queryList.addAll(elementsInSet);
}
List<Element> tmp = Lists.newArrayList(elementsInSet);
Collections.shuffle(tmp, random);
queryList.addAll(tmp.subList(0, extras));
}
// now add bad queries
while (queryList.size() < numQueries) {
Element candidate = newElement();
if (!elementsInSet.contains(candidate)) {
queryList.add(candidate);
}
}
Collections.shuffle(queryList, random);
return queryList.toArray(new Element[0]);
}
private Set<Element> createData() {
Set<Element> set = Sets.newHashSetWithExpectedSize(size);
while (set.size() < size) {
set.add(newElement());
}
return set;
}
private Element newElement() {
int value = random.nextInt();
return isUserTypeFast
? new Element(value)
: new SlowElement(value);
}
static class Element implements Comparable<Element> {
final int hash;
Element(int hash) {
this.hash = hash;
}
@Override public boolean equals(Object obj) {
return this == obj
|| (obj instanceof Element && ((Element) obj).hash == hash);
}
@Override public int hashCode() {
return hash;
}
@Override
public int compareTo(Element that) {
return Ints.compare(hash, that.hash);
}
@Override public String toString() {
return String.valueOf(hash);
}
}
static class SlowElement extends Element {
SlowElement(int hash) {
super(hash);
}
@Override public boolean equals(Object obj) {
return slowItDown() != 1 && super.equals(obj);
}
@Override public int hashCode() {
return slowItDown() + hash;
}
@Override public int compareTo(Element e) {
int x = slowItDown();
return x + super.compareTo(e) - x; // silly attempt to prevent opt
}
static int slowItDown() {
int result = 0;
for (int i = 1; i <= 1000; i++) {
result += i;
}
return result;
}
}
}
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