LilySpecificResponder.java

/*
 * Copyright 2010 Outerthought bvba
 *
 * 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.lilyproject.avro;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.avro.AvroRuntimeException;
import org.apache.avro.Protocol;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.DatumReader;
import org.apache.avro.io.DatumWriter;
import org.apache.avro.io.Encoder;
import org.apache.avro.ipc.generic.GenericResponder;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.specific.SpecificDatumReader;
import org.apache.avro.specific.SpecificDatumWriter;
import org.apache.avro.specific.SpecificRecord;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

// This code is copied from the Avro codebase with some customisations to handle
// remote propagation of runtime exceptions

public class LilySpecificResponder extends GenericResponder {
    private Object impl;
    private SpecificData data;
    private Log log = LogFactory.getLog(getClass());

    public LilySpecificResponder(Class iface, Object impl) {
        this(SpecificData.get().getProtocol(iface), impl);
    }

    public LilySpecificResponder(Protocol protocol, Object impl) {
        this(protocol, impl, SpecificData.get());
    }

    protected LilySpecificResponder(Protocol protocol, Object impl,
                                    SpecificData data) {
        super(protocol);
        this.impl = impl;
        this.data = data;
    }

    @Override
    protected DatumWriter<Object> getDatumWriter(Schema schema) {
        return new SpecificDatumWriter<Object>(schema);
    }

    @Override
    protected DatumReader<Object> getDatumReader(Schema actual, Schema expected) {
        return new SpecificDatumReader<Object>(actual, expected);
    }

    @Override
    public void writeError(Schema schema, Object error,
                           Encoder out) throws IOException {
        getDatumWriter(schema).write(error, out);
    }

    @Override
    public Object respond(Protocol.Message message, Object request) throws Exception {
        int numParams = message.getRequest().getFields().size();
        Object[] params = new Object[numParams];
        Class[] paramTypes = new Class[numParams];
        int i = 0;
        try {
            for (Schema.Field param : message.getRequest().getFields()) {
                params[i] = ((GenericRecord) request).get(param.name());
                paramTypes[i] = data.getClass(param.schema());
                i++;
            }
            Method method = impl.getClass().getMethod(message.getName(), paramTypes);
            method.setAccessible(true);
            return method.invoke(impl, params);
        } catch (InvocationTargetException e) {
            if (e.getTargetException() instanceof SpecificRecord) {
                throw (Exception) e.getTargetException();
            } else {
                throw AvroConverter.convertOtherException(e.getTargetException());
            }
        } catch (NoSuchMethodException e) {
            throw new AvroRuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new AvroRuntimeException(e);
        }
    }

}