org.apache.mina.filter.codec.statemachine.IntegerDecodingState Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.mina.filter.codec.statemachine;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.filter.codec.ProtocolDecoderException;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
/**
* {@link DecodingState} which decodes int
values in big-endian
* order (high bytes come first).
*
* @author Apache MINA Project
*/
public abstract class IntegerDecodingState implements DecodingState {
private int counter;
/**
* {@inheritDoc}
*/
@Override
public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception {
int firstByte = 0;
int secondByte = 0;
int thirdByte = 0;
while (in.hasRemaining()) {
switch (counter) {
case 0:
firstByte = in.getUnsigned();
break;
case 1:
secondByte = in.getUnsigned();
break;
case 2:
thirdByte = in.getUnsigned();
break;
case 3:
counter = 0;
return finishDecode((firstByte << 24) | (secondByte << 16) | (thirdByte << 8) | in.getUnsigned(), out);
default:
throw new InternalError();
}
counter++;
}
return this;
}
/**
* {@inheritDoc}
*/
@Override
public DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception {
throw new ProtocolDecoderException("Unexpected end of session while waiting for an integer.");
}
/**
* Invoked when this state has consumed a complete int
.
*
* @param value the integer.
* @param out the current {@link ProtocolDecoderOutput} used to write
* decoded messages.
* @return the next state if a state transition was triggered (use
* this
for loop transitions) or null
if
* the state machine has reached its end.
* @throws Exception if the read data violated protocol specification.
*/
protected abstract DecodingState finishDecode(int value, ProtocolDecoderOutput out) throws Exception;
}