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/**
* Copyright 2011 Terracotta, Inc.
* Copyright 2011 Oracle America Incorporated
*
* 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 javax.cache.implementation;
import javax.cache.Cache;
import javax.cache.CacheStatistics;
import java.io.Serializable;
import java.util.Date;
import java.util.concurrent.atomic.AtomicLong;
/**
* The reference implementation for JSR107.
* @since 1.0
*/
public class RICacheStatistics implements CacheStatistics, Serializable {
private static final long serialVersionUID = -5589437411679003894L;
private static final long NANOSECONDS_IN_A_MILLISECOND = 1000000L;
private transient Cache cache;
private final AtomicLong cacheRemovals = new AtomicLong();
private final AtomicLong cacheExpiries = new AtomicLong();
private final AtomicLong cachePuts = new AtomicLong();
private final AtomicLong cacheHits = new AtomicLong();
private final AtomicLong cacheMisses = new AtomicLong();
private final AtomicLong cacheEvictions = new AtomicLong();
private final AtomicLong cachePutTimeTakenNanos = new AtomicLong();
private final AtomicLong cacheGetTimeTakenNanos = new AtomicLong();
private final AtomicLong cacheRemoveTimeTakenNanos = new AtomicLong();
private Date lastCollectionStartDate = new Date();
/**
* Constructs a cache statistics object
*
* @param cache the associated cache
*/
public RICacheStatistics(Cache cache) {
this.cache = cache;
}
/**
* {@inheritDoc}
*
* Statistics will also automatically be cleared if internal counters overflow.
*/
@Override
public void clearStatistics() {
cachePuts.set(0);
cacheMisses.set(0);
cacheRemovals.set(0);
cacheExpiries.set(0);
cacheHits.set(0);
cacheEvictions.set(0);
cacheGetTimeTakenNanos.set(0);
cachePutTimeTakenNanos.set(0);
cacheRemoveTimeTakenNanos.set(0);
lastCollectionStartDate = new Date();
}
/**
* The date from which statistics have been accumulated. Because statistics can be cleared, this is not necessarily
* since the cache was started.
*
* @return the date statistics started being accumulated
*/
@Override
public Date getStartAccumulationDate() {
return lastCollectionStartDate;
}
/**
* @return the entry count
*/
public long getEntryCount() {
return ((RICache) cache).getSize();
}
/**
* @return the number of hits
*/
@Override
public long getCacheHits() {
return cacheHits.longValue();
}
/**
* Returns cache hits as a percentage of total gets.
*
* @return the percentage of successful hits, as a decimal
*/
@Override
public float getCacheHitPercentage() {
return getCacheHits() / getCacheGets();
}
/**
* @return the number of misses
*/
@Override
public long getCacheMisses() {
return cacheMisses.longValue();
}
/**
* Returns cache misses as a percentage of total gets.
*
* @return the percentage of accesses that failed to find anything
*/
@Override
public float getCacheMissPercentage() {
return getCacheMisses() / getCacheGets();
}
/**
* The total number of requests to the cache. This will be equal to the sum of the hits and misses.
*
* A "get" is an operation that returns the current or previous value.
*
* @return the number of hits
*/
@Override
public long getCacheGets() {
return getCacheHits() + getCacheMisses();
}
/**
* The total number of puts to the cache.
*
* A put is counted even if it is immediately evicted. A replace includes a put and remove.
*
* @return the number of hits
*/
@Override
public long getCachePuts() {
return cachePuts.longValue();
}
/**
* The total number of removals from the cache. This does not include evictions, where the cache itself
* initiates the removal to make space.
*
* A replace invcludes a put and remove.
*
* @return the number of hits
*/
@Override
public long getCacheRemovals() {
return cacheRemovals.longValue();
}
/**
* @return the number of evictions from the cache
*/
@Override
public long getCacheEvictions() {
return cacheEvictions.longValue();
}
/**
* The mean time to execute gets.
*
* @return the time in milliseconds
*/
@Override
public float getAverageGetMillis() {
return (cacheGetTimeTakenNanos.longValue() / getCacheGets()) / NANOSECONDS_IN_A_MILLISECOND;
}
/**
* The mean time to execute puts.
*
* @return the time in milliseconds
*/
@Override
public float getAveragePutMillis() {
return (cachePutTimeTakenNanos.longValue() / getCacheGets()) / NANOSECONDS_IN_A_MILLISECOND;
}
/**
* The mean time to execute removes.
*
* @return the time in milliseconds
*/
@Override
public float getAverageRemoveMillis() {
return (cacheRemoveTimeTakenNanos.longValue() / getCacheGets()) / NANOSECONDS_IN_A_MILLISECOND;
}
//package local incrementers
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCacheRemovals(long number) {
cacheRemovals.getAndAdd(number);
}
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCacheExpiries(long number) {
cacheExpiries.getAndAdd(number);
}
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCachePuts(long number) {
cachePuts.getAndAdd(number);
}
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCacheHits(long number) {
cacheHits.getAndAdd(number);
}
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCacheMisses(long number) {
cacheMisses.getAndAdd(number);
}
/**
* Increases the counter by the number specified.
* @param number the number to increase the counter by
*/
void increaseCacheEvictions(long number) {
cacheEvictions.getAndAdd(number);
}
/**
* Increments the get time accumulator
* @param duration the time taken in nanoseconds
*/
public void addGetTimeNano(long duration) {
if (cacheGetTimeTakenNanos.get() <= Long.MAX_VALUE - duration) {
cacheGetTimeTakenNanos.addAndGet(duration);
} else {
//counter full. Just reset.
clearStatistics();
cacheGetTimeTakenNanos.set(duration);
}
}
/**
* Increments the put time accumulator
* @param duration the time taken in nanoseconds
*/
public void addPutTimeNano(long duration) {
if (cachePutTimeTakenNanos.get() <= Long.MAX_VALUE - duration) {
cachePutTimeTakenNanos.addAndGet(duration);
} else {
//counter full. Just reset.
clearStatistics();
cachePutTimeTakenNanos.set(duration);
}
}
/**
* Increments the remove time accumulator
* @param duration the time taken in nanoseconds
*/
public void addRemoveTimeNano(long duration) {
if (cacheRemoveTimeTakenNanos.get() <= Long.MAX_VALUE - duration) {
cacheRemoveTimeTakenNanos.addAndGet(duration);
} else {
//counter full. Just reset.
clearStatistics();
cacheRemoveTimeTakenNanos.set(duration);
}
}
}
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