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 io.milton.httpclient; import java.io.BufferedInputStream; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import org.apache.commons.io.FileUtils; import org.apache.commons.io.IOUtils; public class NotifyingFileInputStream extends InputStream { private final InputStream fin; private final InputStream wrapped; private final ProgressListener listener; private final String fileName; private long pos; private final Long totalLength; // the system time we last notified the progress listener private long timeLastNotify; private long bytesSinceLastNotify; public NotifyingFileInputStream(File f, ProgressListener listener) throws FileNotFoundException, IOException { this.fin = FileUtils.openInputStream(f); this.wrapped = new BufferedInputStream(fin); this.listener = listener; this.totalLength = f.length(); this.fileName = f.getAbsolutePath(); this.timeLastNotify = System.currentTimeMillis(); } /** * * @param in - the input stream containing file data * @param length - maybe null if unknown * @param path * @param listener * @throws IOException */ public NotifyingFileInputStream(InputStream in, Long length, String path, ProgressListener listener) throws IOException { this.fin = in; this.wrapped = new BufferedInputStream(fin); this.listener = listener; this.totalLength = length; this.fileName = path; this.timeLastNotify = System.currentTimeMillis(); } @Override public int read() throws IOException { increment(1); return wrapped.read(); } @Override public int read(byte[] b) throws IOException { increment(b.length); return wrapped.read(b); } @Override public int read(byte[] b, int off, int len) throws IOException { increment(len); return wrapped.read(b, off, len); } private void increment(int len) { pos += len; notifyListener(len); } void notifyListener(int numBytes) { if (listener == null) { return; } listener.onRead(numBytes); bytesSinceLastNotify += numBytes; if (bytesSinceLastNotify < 1000) { // log.trace( "notifyListener: not enough bytes: " + bytesSinceLastNotify); return; } int timeDiff = (int) (System.currentTimeMillis() - timeLastNotify); if (timeDiff > 10) { timeLastNotify = System.currentTimeMillis(); listener.onProgress(pos, totalLength, fileName); bytesSinceLastNotify = 0; } } @Override public void close() throws IOException { IOUtils.closeQuietly(wrapped); IOUtils.closeQuietly(fin); super.close(); } }