001/* 002 * Copyright (C) 2007 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 005 * in compliance with the License. You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software distributed under the License 010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 011 * or implied. See the License for the specific language governing permissions and limitations under 012 * the License. 013 */ 014 015package com.google.common.io; 016 017import static com.google.common.base.Preconditions.checkNotNull; 018 019import com.google.common.annotations.Beta; 020import com.google.common.annotations.GwtIncompatible; 021import java.io.FilterOutputStream; 022import java.io.IOException; 023import java.io.OutputStream; 024 025/** 026 * An OutputStream that counts the number of bytes written. 027 * 028 * @author Chris Nokleberg 029 * @since 1.0 030 */ 031@Beta 032@GwtIncompatible 033public final class CountingOutputStream extends FilterOutputStream { 034 035 private long count; 036 037 /** 038 * Wraps another output stream, counting the number of bytes written. 039 * 040 * @param out the output stream to be wrapped 041 */ 042 public CountingOutputStream(OutputStream out) { 043 super(checkNotNull(out)); 044 } 045 046 /** Returns the number of bytes written. */ 047 public long getCount() { 048 return count; 049 } 050 051 @Override 052 public void write(byte[] b, int off, int len) throws IOException { 053 out.write(b, off, len); 054 count += len; 055 } 056 057 @Override 058 public void write(int b) throws IOException { 059 out.write(b); 060 count++; 061 } 062 063 // Overriding close() because FilterOutputStream's close() method pre-JDK8 has bad behavior: 064 // it silently ignores any exception thrown by flush(). Instead, just close the delegate stream. 065 // It should flush itself if necessary. 066 @Override 067 public void close() throws IOException { 068 out.close(); 069 } 070}