org.apache.mina.filter.codec.statemachine.ConsumeToDynamicTerminatorDecodingState Maven / Gradle / Ivy
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* 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.ProtocolDecoderOutput;
/**
* {@link DecodingState} which consumes all bytes until a fixed (ASCII)
* character is reached. The terminator is skipped.
*
* @author Apache MINA Project
*/
public abstract class ConsumeToDynamicTerminatorDecodingState implements DecodingState {
private IoBuffer buffer;
/**
* {@inheritDoc}
*/
@Override
public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception {
int beginPos = in.position();
int terminatorPos = -1;
int limit = in.limit();
for (int i = beginPos; i < limit; i++) {
byte b = in.get(i);
if (isTerminator(b)) {
terminatorPos = i;
break;
}
}
if (terminatorPos >= 0) {
IoBuffer product;
if (beginPos < terminatorPos) {
in.limit(terminatorPos);
if (buffer == null) {
product = in.slice();
} else {
buffer.put(in);
product = buffer.flip();
buffer = null;
}
in.limit(limit);
} else {
// When input contained only terminator rather than actual data...
if (buffer == null) {
product = IoBuffer.allocate(0);
} else {
product = buffer.flip();
buffer = null;
}
}
in.position(terminatorPos + 1);
return finishDecode(product, out);
}
if (buffer == null) {
buffer = IoBuffer.allocate(in.remaining());
buffer.setAutoExpand(true);
}
buffer.put(in);
return this;
}
/**
* {@inheritDoc}
*/
@Override
public DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception {
IoBuffer product;
// When input contained only terminator rather than actual data...
if (buffer == null) {
product = IoBuffer.allocate(0);
} else {
product = buffer.flip();
buffer = null;
}
return finishDecode(product, out);
}
/**
* Determines whether the specified byte
is a terminator.
*
* @param b the byte
to check.
* @return true if b
is a terminator,
* false otherwise.
*/
protected abstract boolean isTerminator(byte b);
/**
* Invoked when this state has reached the terminator byte.
*
* @param product the read bytes not including the terminator.
* @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(IoBuffer product, ProtocolDecoderOutput out) throws Exception;
}