1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.filter.stream;
21
22 import java.io.IOException;
23
24 import org.apache.mina.core.buffer.IoBuffer;
25 import org.apache.mina.core.file.FileRegion;
26 import org.apache.mina.core.session.IoSession;
27
28 /**
29 * Filter implementation that converts a {@link FileRegion} to {@link IoBuffer}
30 * objects and writes those buffers to the next filter. When end of the
31 * {@code FileRegion} has been reached this filter will call
32 * {@link org.apache.mina.core.filterchain.IoFilter.NextFilter#messageSent(org.apache.mina.core.session.IoSession, org.apache.mina.core.write.WriteRequest)} using the
33 * original {@link FileRegion} written to the session and notifies
34 * {@link org.apache.mina.core.future.WriteFuture} on the original
35 * {@link org.apache.mina.core.write.WriteRequest}.
36 * <p>Normall {@code FileRegion} objects should be handled by the
37 * {@link org.apache.mina.core.service.IoProcessor} but this is not always possible
38 * if a filter is being used that needs to modify the contents of the file
39 * before sending over the network (i.e. the
40 * {@link org.apache.mina.filter.ssl.SslFilter} or a data compression filter.)
41 * </p>
42 * <p> This filter will ignore written messages which aren't {@link FileRegion}
43 * instances. Such messages will be passed to the next filter directly.
44 * </p>
45 * <p><b>NOTE:</b> this filter does not close the file channel in
46 * {@link FileRegion#getFileChannel()} after the data from the file has been
47 * written. The {@code FileChannel} should be closed in either
48 * {@link org.apache.mina.core.service.IoHandler#messageSent(IoSession,Object)}
49 * or in an {@link org.apache.mina.core.future.IoFutureListener} associated with the
50 * {@code WriteFuture}.
51 * </p>
52 *
53 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
54 * @org.apache.xbean.XBean
55 */
56 public class FileRegionWriteFilter extends AbstractStreamWriteFilter<FileRegion> {
57 /**
58 * {@inheritDoc}
59 */
60 @Override
61 protected Class<FileRegion> getMessageClass() {
62 return FileRegion.class;
63 }
64
65 /**
66 * {@inheritDoc}
67 */
68 @Override
69 protected IoBuffer getNextBuffer(FileRegion fileRegion) throws IOException {
70 // If there are no more bytes to read, return null
71 if (fileRegion.getRemainingBytes() <= 0) {
72 return null;
73 }
74
75 // Allocate the buffer for reading from the file
76 int bufferSize = (int) Math.min(getWriteBufferSize(), fileRegion.getRemainingBytes());
77 IoBuffer buffer = IoBuffer.allocate(bufferSize);
78
79 // Read from the file
80 int bytesRead = fileRegion.getFileChannel().read(buffer.buf(), fileRegion.getPosition());
81 fileRegion.update(bytesRead);
82
83 // return the buffer
84 buffer.flip();
85
86 return buffer;
87 }
88 }