Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.jackrabbit.oak.spi.blob.stats; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; import java.util.concurrent.TimeUnit; import com.google.common.io.CountingInputStream; public final class StatsCollectingStreams { public static InputStream wrap(final BlobStatsCollector collector, final String blobId, InputStream in) { final CountingInputStream cin = new CountingInputStream(in); return new FilterInputStream(cin) { final long startTime = System.nanoTime(); @Override public void close() throws IOException { super.close(); //We rely on close to determine how much was downloaded //as once an InputStream is exposed its not possible to //determine if the stream is actually used //Download time might not be accurate as reading code might //be processing also as it moved further in stream. So that //overhead would add to the download time collector.downloaded(blobId, System.nanoTime() - startTime, TimeUnit.NANOSECONDS, cin.getCount()); collector.downloadCompleted(blobId); } }; } }