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/*
* Copyright 2010 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* 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.amazon.carbonado.capability;
import java.io.Serializable;
import java.util.Collection;
import com.amazon.carbonado.Cursor;
import com.amazon.carbonado.Repository;
import com.amazon.carbonado.RepositoryException;
/**
* Defines a remote procedure which can be executed by {@link
* RemoteProcedureCapability}. Any data within the procedure instance is
* serialized to the remote host, and possibly the class definition
* too. Execution might have security restrictions applied.
*
* <p>The RemoteProcedure instance is Serializable, and so and serializable
* parameters can be passed with it. Storables and extra data can be sent
* through the {@link Request} object. Any data returned by procedure
* implementation must be sent through the {@link Reply} object.
*
* @param <R> reply object type
* @param <D> request data object type
* @author Brian S O'Neill
*/
public interface RemoteProcedure<R, D> extends Serializable {
/**
* Request handler for remote procedure implementation.
*
* @param repo repository as seen by host that procedure is running from
* @param request non-null request object
* @return false if request is still active when this method returns;
* request must eventually be explicitly finished
*/
boolean handleRequest(Repository repo, Request<R, D> request) throws RepositoryException;
/**
* Client-side call into a remote procedure. To avoid leaking resources,
* the finish method must be invoked or all reply data be fully read. If an
* exception is thrown by a method defined in this interface, resources are
* automatically released.
*
* @param <R> reply object type
* @param <D> request data object type
* @see RemoteProcedureCapability#beginCall
*/
public static interface Call<R, D> {
/**
* Send data to the remote procedure.
*
* @return this Call instance
* @throws IllegalArgumentException if data is null
* @throws IllegalStateException if a call has been executed
*/
Call<R, D> send(D data) throws RepositoryException;
/**
* Send all data from the given cursor to the remote procedure.
*
* @return this Call instance
* @throws IllegalArgumentException if data is null
* @throws IllegalStateException if a call has been executed
*/
Call<R, D> sendAll(Cursor<? extends D> cursor) throws RepositoryException;
/**
* Reset the internal object stream of the call, allowing cached
* objects to get freed.
*
* @return this Call instance
* @throws IllegalStateException if a call has been executed
*/
Call<R, D> reset() throws RepositoryException;
/**
* Flushes all the data sent so far. Flush is invoked automatically
* when call is executed.
*/
void flush() throws RepositoryException;
/**
* Executes the call and receive a reply. Calling this method does not
* block, but methods on the returned Cursor may block waiting for
* data.
*
* @throws IllegalStateException if a call has been executed
*/
Cursor<R> fetchReply() throws RepositoryException;
/**
* Executes the call without expecting a reply. Method blocks waiting
* for procedure to finish.
*
* @throws IllegalStateException if a call has been executed
*/
void execute() throws RepositoryException;
/**
* Executes the call without expecting a reply. Method does not block
* waiting for procedure to finish. Asynchronous execution is not
* allowed if the current thread is in a transaction. This is because
* transaction ownership becomes ambiguous.
*
* @throws IllegalStateException if a call has been executed or if
* current thread is in a transaction
*/
void executeAsync() throws RepositoryException;
}
/**
* Request into a remote procedure, as seen by procedure implementation. To
* avoid leaking resources, the request or reply object must always be
* finished. If an exception is thrown by a method defined in this
* interface, resources are automatically released.
*
* @param <R> reply object type
* @param <D> request data object type
*/
public static interface Request<R, D> {
/**
* Receive data from caller.
*
* @return null if no more data
*/
D receive() throws RepositoryException;
/**
* Receive all remaining data from caller.
*
* @param c collection to receive data
* @return amount received
*/
int receiveInto(Collection<? super D> c) throws RepositoryException;
/**
* Begin a reply after receiving all data. If no data is expected,
* reply can be made without calling receive.
*
* @throws IllegalStateException if reply was already begun or if
* request is finished
*/
Reply<R> beginReply() throws RepositoryException;
/**
* Reply and immediately finish, without sending and data to caller.
*
* @throws IllegalStateException if a reply was already begun
*/
void finish() throws RepositoryException;
}
/**
* Reply from remote procedure implementation. To avoid leaking resources,
* the finish method must always be invoked. If an exception is thrown by a
* method defined in this interface, resources are automatically released.
*
* @param <R> reply object type
*/
public static interface Reply<R> {
/**
* Send reply data to the caller.
*
* @return this Reply instance
* @throws IllegalStateException if reply is finished
*/
Reply<R> send(R data) throws RepositoryException;
/**
* Reply with all data from the given cursor to the caller.
*
* @return this Reply instance
* @throws IllegalStateException if reply is finished
*/
Reply<R> sendAll(Cursor<? extends R> cursor) throws RepositoryException;
/**
* Reset the internal object stream of the reply, allowing cached
* objects to get freed.
*
* @return this Reply instance
* @throws IllegalStateException if reply is finished
*/
Reply<R> reset() throws RepositoryException;
/**
* Flushes all the data sent so far. Flush is invoked automatically
* when reply is finished.
*/
void flush() throws RepositoryException;
/**
* Finish the reply.
*/
void finish() throws RepositoryException;
}
}
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