01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one
03: * or more contributor license agreements. See the NOTICE file
04: * distributed with this work for additional information
05: * regarding copyright ownership. The ASF licenses this file
06: * to you under the Apache License, Version 2.0 (the
07: * "License"); you may not use this file except in compliance
08: * with the License. You may obtain a copy of the License at
09: *
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.util;
21:
22: import org.apache.mina.common.IoEventType;
23: import org.apache.mina.common.IoFilter;
24: import org.apache.mina.common.IoFilterAdapter;
25: import org.apache.mina.common.IoSession;
26: import org.apache.mina.common.WriteRequest;
27: import org.apache.mina.common.WriteRequestWrapper;
28:
29: /**
30: * An abstract {@link IoFilter} that simplifies the implementation of
31: * an {@link IoFilter} that filters an {@link IoEventType#WRITE} event.
32: *
33: * @author The Apache MINA Project (dev@mina.apache.org)
34: * @version $Rev: 594773 $, $Date: 2007-11-13 22:27:14 -0700 (Tue, 13 Nov 2007) $
35: *
36: */
37: public abstract class WriteRequestFilter extends IoFilterAdapter {
38:
39: @Override
40: public void exceptionCaught(NextFilter nextFilter,
41: IoSession session, Throwable cause) throws Exception {
42: nextFilter.exceptionCaught(session, cause);
43: }
44:
45: @Override
46: public void filterWrite(NextFilter nextFilter, IoSession session,
47: WriteRequest writeRequest) throws Exception {
48: Object filteredMessage = doFilterWrite(nextFilter, session,
49: writeRequest);
50: if (filteredMessage != null
51: && filteredMessage != writeRequest.getMessage()) {
52: nextFilter.filterWrite(session, new FilteredWriteRequest(
53: filteredMessage, writeRequest));
54: } else {
55: nextFilter.filterWrite(session, writeRequest);
56: }
57: }
58:
59: @Override
60: public void messageSent(NextFilter nextFilter, IoSession session,
61: WriteRequest writeRequest) throws Exception {
62: if (writeRequest instanceof FilteredWriteRequest) {
63: FilteredWriteRequest req = (FilteredWriteRequest) writeRequest;
64: if (req.getParent() == this ) {
65: nextFilter.messageSent(session, req.getParentRequest());
66: return;
67: }
68: }
69:
70: nextFilter.messageSent(session, writeRequest);
71: }
72:
73: protected abstract Object doFilterWrite(NextFilter nextFilter,
74: IoSession session, WriteRequest writeRequest)
75: throws Exception;
76:
77: private class FilteredWriteRequest extends WriteRequestWrapper {
78: private final Object filteredMessage;
79:
80: public FilteredWriteRequest(Object filteredMessage,
81: WriteRequest writeRequest) {
82: super (writeRequest);
83:
84: if (filteredMessage == null) {
85: throw new NullPointerException("filteredMessage");
86: }
87: this .filteredMessage = filteredMessage;
88: }
89:
90: public WriteRequestFilter getParent() {
91: return WriteRequestFilter.this ;
92: }
93:
94: @Override
95: public Object getMessage() {
96: return filteredMessage;
97: }
98: }
99: }
|