001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.mina.filter.codec.prefixedstring;
021
022import org.apache.mina.core.buffer.BufferDataException;
023import org.apache.mina.core.session.IoSession;
024import org.apache.mina.filter.codec.ProtocolCodecFactory;
025import org.apache.mina.filter.codec.ProtocolDecoder;
026import org.apache.mina.filter.codec.ProtocolEncoder;
027
028import java.nio.charset.Charset;
029
030/**
031 * A {@link ProtocolCodecFactory} that performs encoding and decoding
032 * of a Java String object using a fixed-length length prefix.
033 *
034 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
035 */
036public class PrefixedStringCodecFactory implements ProtocolCodecFactory {
037
038    private final PrefixedStringEncoder encoder;
039
040    private final PrefixedStringDecoder decoder;
041
042    public PrefixedStringCodecFactory(Charset charset) {
043        encoder = new PrefixedStringEncoder(charset);
044        decoder = new PrefixedStringDecoder(charset);
045    }
046
047    public PrefixedStringCodecFactory() {
048        this(Charset.defaultCharset());
049    }
050
051    /**
052     * Returns the allowed maximum size of an encoded string.
053     * If the size of the encoded String exceeds this value, the encoder
054     * will throw a {@link IllegalArgumentException}.
055     * The default value is {@link PrefixedStringEncoder#DEFAULT_MAX_DATA_LENGTH}.
056     * <p>
057     * This method does the same job as {@link PrefixedStringEncoder#setMaxDataLength(int)}.
058     *
059     * @return the allowed maximum size of an encoded string.
060     */
061    public int getEncoderMaxDataLength() {
062        return encoder.getMaxDataLength();
063    }
064
065    /**
066     * Sets the allowed maximum size of an encoded String.
067     * If the size of the encoded String exceeds this value, the encoder
068     * will throw a {@link IllegalArgumentException}.
069     * The default value is {@link PrefixedStringEncoder#DEFAULT_MAX_DATA_LENGTH}.
070     * <p>
071     * This method does the same job as {@link PrefixedStringEncoder#getMaxDataLength()}.
072     *
073     * @param maxDataLength allowed maximum size of an encoded String.
074     */
075    public void setEncoderMaxDataLength(int maxDataLength) {
076        encoder.setMaxDataLength(maxDataLength);
077    }
078
079    /**
080     * @return the allowed maximum size of a decoded string.
081     * <p>
082     * This method does the same job as {@link PrefixedStringEncoder#setMaxDataLength(int)}.
083     * @see #setDecoderMaxDataLength(int)
084     */
085    public int getDecoderMaxDataLength() {
086        return decoder.getMaxDataLength();
087    }
088
089    /**
090     * Sets the maximum allowed value specified as data length in the decoded data
091     * <p>
092     * Useful for preventing an OutOfMemory attack by the peer.
093     * The decoder will throw a {@link BufferDataException} when data length
094     * specified in the incoming data is greater than maxDataLength
095     * The default value is {@link PrefixedStringDecoder#DEFAULT_MAX_DATA_LENGTH}.
096     * <p>
097     * This method does the same job as {@link PrefixedStringDecoder#setMaxDataLength(int)}.
098     *
099     * @param maxDataLength maximum allowed value specified as data length in the incoming data
100     */
101    public void setDecoderMaxDataLength(int maxDataLength) {
102        decoder.setMaxDataLength(maxDataLength);
103    }
104
105    /**
106     * Sets the length of the prefix used by the decoder
107     *
108     * @param prefixLength the length of the length prefix (1, 2, or 4)
109     */
110    public void setDecoderPrefixLength(int prefixLength) {
111        decoder.setPrefixLength(prefixLength);
112    }
113
114    /**
115     * Gets the length of the length prefix (1, 2, or 4) used by the decoder
116     *
117     * @return length of the length prefix
118     */
119    public int getDecoderPrefixLength() {
120        return decoder.getPrefixLength();
121    }
122
123    /**
124     * Sets the length of the prefix used by the encoder
125     *
126     * @param prefixLength the length of the length prefix (1, 2, or 4)
127     */
128    public void setEncoderPrefixLength(int prefixLength) {
129        encoder.setPrefixLength(prefixLength);
130    }
131
132    /**
133     * Gets the length of the length prefix (1, 2, or 4) used by the encoder
134     *
135     * @return length of the length prefix
136     */
137    public int getEncoderPrefixLength() {
138        return encoder.getPrefixLength();
139    }
140
141    public ProtocolEncoder getEncoder(IoSession session) throws Exception {
142        return encoder;
143    }
144
145    public ProtocolDecoder getDecoder(IoSession session) throws Exception {
146        return decoder;
147    }
148}