1 /*
2  * Copyright (C) 2007 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.google.common.io;
18 
19 import com.google.common.annotations.Beta;
20 
21 import java.io.FilterOutputStream;
22 import java.io.IOException;
23 import java.io.OutputStream;
24 
25 import javax.annotation.Nullable;
26 
27 /**
28  * An OutputStream that counts the number of bytes written.
29  *
30  * @author Chris Nokleberg
31  * @since 1.0
32  */
33 @Beta
34 public final class CountingOutputStream extends FilterOutputStream {
35 
36   private long count;
37 
38   /**
39    * Wraps another output stream, counting the number of bytes written.
40    *
41    * @param out the output stream to be wrapped
42    */
CountingOutputStream(@ullable OutputStream out)43   public CountingOutputStream(@Nullable OutputStream out) {
44     super(out);
45   }
46 
47   /** Returns the number of bytes written. */
getCount()48   public long getCount() {
49     return count;
50   }
51 
write(byte[] b, int off, int len)52   @Override public void write(byte[] b, int off, int len) throws IOException {
53     out.write(b, off, len);
54     count += len;
55   }
56 
write(int b)57   @Override public void write(int b) throws IOException {
58     out.write(b);
59     count++;
60   }
61 
62   // Overriding close() because FilterOutputStream's close() method pre-JDK8 has bad behavior:
63   // it silently ignores any exception thrown by flush(). Instead, just close the delegate stream.
64   // It should flush itself if necessary.
close()65   @Override public void close() throws IOException {
66     out.close();
67   }
68 }
69