provider/fastbin/src/main/java/org/apache/aries/rsa/provider/fastbin/tcp/BlockingInvocationStrategy.java

/*
 * 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.aries.rsa.provider.fastbin.tcp;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.rmi.RemoteException;
import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;

import org.apache.aries.rsa.provider.fastbin.api.AsyncCallback;
import org.apache.aries.rsa.provider.fastbin.api.SerializationStrategy;
import org.fusesource.hawtbuf.DataByteArrayInputStream;
import org.fusesource.hawtbuf.DataByteArrayOutputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * <p>
 * </p>
 *
 */
@SuppressWarnings("rawtypes")
public class BlockingInvocationStrategy extends AbstractInvocationStrategy {

    protected static final Logger LOGGER = LoggerFactory.getLogger(BlockingInvocationStrategy.class);

    private static final Callable<Object> EMPTY_CALLABLE = new Callable<Object>() {
        public Object call() {
            return null;
        }
    };

    private class BlockingResponseFuture extends FutureTask<Object> implements ResponseFuture, AsyncCallback {

        private final ClassLoader loader;
        private final Method method;
        private final SerializationStrategy serializationStrategy;

        public BlockingResponseFuture(ClassLoader loader, Method method, SerializationStrategy serializationStrategy) {
            super(EMPTY_CALLABLE);
            this.loader = loader;
            this.method = method;
            this.serializationStrategy = serializationStrategy;
        }

        public void set(DataByteArrayInputStream source) throws IOException, ClassNotFoundException {
            try {
                serializationStrategy.decodeResponse(loader, method.getReturnType(), source, this);
            } catch (Throwable e) {
                super.setException(e);
            }
        }

        public void fail(Throwable failure) {
            super.setException(failure);
        }

        public void onSuccess(Object result) {
            super.set(result);
        }

        public void onFailure(Throwable failure) {
            super.setException(failure);
        }
    }

    @Override
    protected ResponseFuture createResponse(SerializationStrategy serializationStrategy, ClassLoader loader, Method method, Object[] args) throws Exception {
        return new BlockingResponseFuture(loader, method, serializationStrategy);
    }

    public void doService(SerializationStrategy serializationStrategy, ClassLoader loader, Method method, Object target, DataByteArrayInputStream requestStream, DataByteArrayOutputStream responseStream, Runnable onComplete) {

        int pos = responseStream.position();
        try {

            Object value = null;
            Throwable error = null;

            try {
                Class<?>[] types = method.getParameterTypes();
                final Object[] args = new Object[types.length];
                serializationStrategy.decodeRequest(loader, types, requestStream, args);
                value = method.invoke(target, args);
                if(isStream(method.getReturnType())) {
                    value = replaceStream(value);
                }
            } catch (Throwable t) {
                if (t instanceof InvocationTargetException) {
                    error = t.getCause();
                } else {
                    error = t;
                }
            }

            serializationStrategy.encodeResponse(loader, method.getReturnType(), value, error, responseStream);

        } catch(Exception e) {

            LOGGER.warn("Initial Encoding response for method "+method+" failed. Retrying", e);
            // we failed to encode the response.. reposition and write that error.
            try {
                responseStream.position(pos);
                serializationStrategy.encodeResponse(loader, method.getReturnType(), null, new RemoteException(e.toString()), responseStream);
            } catch (Exception unexpected) {
                LOGGER.error("Error while servicing "+method, unexpected);
            }

        } finally {
            onComplete.run();
        }
    }

}