/* RequestCounter.java
*
* Copyright 2009-2012 Comcast Interactive Media, LLC.
*
* 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 org.fishwife.jrugged;
import java.util.concurrent.Callable;
/**
* This is a statistics wrapper that counts total requests, as well as how many succeed
* and how many fail. This class can be polled periodically to measure request rates,
* success rates, and failure rates.
*/
public class RequestCounter implements ServiceWrapper {
private long numRequests = 0L;
private long numSuccesses = 0L;
private long numFailures = 0L;
/** Default constructor. */
public RequestCounter() {
}
private synchronized void succeed() {
numRequests++;
numSuccesses++;
}
private synchronized void fail() {
numRequests++;
numFailures++;
}
/**
* Wrap the given service call with the {@link RequestCounter} to count the number of
* calls made.
*
* @param c
* the {@link Callable} to attempt
*
* @return whatever c would return on success
*
* @throws Exception
* if <code>c</code> throws one during execution
*/
@Override
public <T> T invoke(final Callable<T> c) throws Exception {
try {
final T result = c.call();
succeed();
return result;
} catch (final Exception e) {
fail();
throw e;
}
}
/**
* Wrap the given service call with the {@link RequestCounter} to count the number of
* calls made.
*
* @param r
* the {@link Runnable} to attempt
*
* @throws Exception
* if <code>c</code> throws one during execution
*/
@Override
public void invoke(final Runnable r) throws Exception {
try {
r.run();
succeed();
} catch (final Exception e) {
fail();
throw e;
}
}
/**
* Wrap the given service call with the {@link RequestCounter} to count the number of
* calls made.
*
* @param r
* the {@link Runnable} to attempt
* @param result
* what to return after <code>r</code> succeeds
*
* @return result
*
* @throws Exception
* if <code>c</code> throws one during execution
*/
@Override
public <T> T invoke(final Runnable r, final T result) throws Exception {
try {
r.run();
succeed();
return result;
} catch (final Exception e) {
fail();
throw e;
}
}
/**
* Samples the current counts.
*
* @return an array of three <code>longs</code>: the total number of requests, the
* number of successful requests, and the number of failed requests.
*/
public synchronized long[] sample() {
return new long[] { numRequests, numSuccesses, numFailures };
}
}