/*
* Copyright (C) 2012-2013 Facebook, Inc.
*
* 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 com.facebook.nifty.processor;
import com.facebook.nifty.core.RequestContext;
import org.apache.thrift.TException;
import org.apache.thrift.TProcessor;
import org.apache.thrift.TProcessorFactory;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.transport.TTransport;
public class NiftyProcessorAdapters
{
/**
* Adapt a {@link TProcessor} to a standard Thrift {@link NiftyProcessor}. Nifty uses this
* internally to adapt the processors generated by the standard Thrift code generator into
* instances of {@link NiftyProcessor} usable by {@link com.facebook.nifty.core.NiftyDispatcher}
*/
public static NiftyProcessor processorFromTProcessor(final TProcessor standardThriftProcessor)
{
checkProcessMethodSignature();
return new NiftyProcessor()
{
@Override
public boolean process(TProtocol in, TProtocol out, RequestContext requestContext) throws TException
{
return standardThriftProcessor.process(in, out);
}
};
}
/**
* Create a {@link NiftyProcessorFactory} that always returns the same {@link NiftyProcessor}
* adapted from the given standard Thrift {@link TProcessor}
*/
public static NiftyProcessorFactory factoryFromTProcessor(final TProcessor standardThriftProcessor)
{
checkProcessMethodSignature();
return new NiftyProcessorFactory()
{
@Override
public NiftyProcessor getProcessor(TTransport transport)
{
return processorFromTProcessor(standardThriftProcessor);
}
};
}
/**
* Create a {@link NiftyProcessorFactory} that delegates to a standard Thrift {@link TProcessorFactory}
* to construct an instance, then adapts each instance to a {@link NiftyProcessor}
*/
public static NiftyProcessorFactory factoryFromTProcessorFactory(final TProcessorFactory standardThriftProcessorFactory)
{
checkProcessMethodSignature();
return new NiftyProcessorFactory()
{
@Override
public NiftyProcessor getProcessor(TTransport transport)
{
return processorFromTProcessor(standardThriftProcessorFactory.getProcessor
(transport));
}
};
}
/**
* Adapt a {@link NiftyProcessor} to a standard Thrift {@link TProcessor}. The {@link
* RequestContext} will always be {@code null}
*/
public static TProcessor processorToTProcessor(final NiftyProcessor niftyProcessor)
{
return new TProcessor()
{
@Override
public boolean process(TProtocol in, TProtocol out) throws TException
{
return niftyProcessor.process(in, out, null);
}
};
}
/**
* Create a standard thrift {@link TProcessorFactory} that always returns the same
* {@link TProcessor} adapted from the given {@link NiftyProcessor}
*/
public static TProcessorFactory processorToTProcessorFactory(final NiftyProcessor niftyProcessor)
{
return new TProcessorFactory(processorToTProcessor(niftyProcessor));
}
/**
* Create a standard thrift {@link TProcessorFactory} that delegates to a
* {@link NiftyProcessorFactory} to construct an instance, then adapts each instance to a
* standard Thrift {@link TProcessor}
*/
public static TProcessorFactory processorFactoryToTProcessorFactory(final NiftyProcessorFactory niftyProcessorFactory)
{
return new TProcessorFactory(null) {
@Override
public TProcessor getProcessor(TTransport trans)
{
return processorToTProcessor(niftyProcessorFactory.getProcessor(trans));
}
};
}
/**
* Catch the mismatch early if someone tries to pass our internal variant of TProcessor with
* a different signature on the process() method into these adapters.
*/
private static void checkProcessMethodSignature()
{
try {
TProcessor.class.getMethod("process", TProtocol.class, TProtocol.class);
}
catch (NoSuchMethodException e) {
// Facebook's TProcessor variant needs processor adapters from a different package
throw new IllegalStateException("The loaded TProcessor class is not supported by version of the adapters");
}
}
}