/*
* Copyright (C) 2012 Red Hat, Inc. and/or its affiliates.
*
* Licensed 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.jboss.errai.bus.server.io;
import java.io.IOException;
import org.jboss.errai.bus.server.io.buffers.BufferFilter;
/**
* This {@link BufferFilter} is used for re-writing the data in the buffer to permit properly formed
* multi-message payloads. This is because ErraiBus J.REP messages are delivered into the bus as
* single-message payloads. This filter prepends '<tt>[</tt>' to the data coming from the buffer,
* and inserts a '<tt>,</tt>' between each message in the stream. It then appends a '<tt>]</tt>' to the
* message to complete the payload.
* <p/>
* For instance, consider the following buffer data:
* <p/>
* <code>
* {"foo":"bar"}{"bar":"foo"}
* </code>
* <p/>
* This filter will transform this to:
* <p/>
* <code>
* [{"foo":"bar"},{"bar":"foo"}]
* </code>
*
* @author Mike Brock
*/
public class MultiMessageFilter implements BufferFilter {
int brackCount;
int seg;
boolean inString;
boolean escape;
@Override
public void before(final ByteWriteAdapter outstream) throws IOException {
outstream.write('[');
}
@Override
public int each(int i, final ByteWriteAdapter outstream) throws IOException {
if (inString) {
if (escape) {
escape = false;
}
else if (i == '\\') {
escape = true;
}
else if (i == '"') {
inString = false;
}
}
else {
if (i == '"') {
inString = true;
}
else if (i == '{' && ++brackCount == 1 && seg != 0) {
outstream.write(',');
}
else if (i == '}' && brackCount != 0 && --brackCount == 0) {
seg++;
}
}
return i;
}
@Override
public void after(final ByteWriteAdapter outstream) throws IOException {
if (brackCount == 1) {
outstream.write('}');
}
outstream.write(']');
}
}