| /* |
| * 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.druid.frame.channel; |
| |
| import com.google.common.util.concurrent.ListenableFuture; |
| import org.apache.druid.frame.Frame; |
| |
| import javax.annotation.Nullable; |
| import java.io.Closeable; |
| import java.io.IOException; |
| |
| /** |
| * Interface for writing a sequence of frames. Supports nonblocking writes through the {@link #writabilityFuture()} |
| * method. |
| * |
| * May be implemented using an in-memory queue, disk file, stream, etc. |
| * |
| * Channels implementing this interface are used by a single writer; they do not support concurrent writes. |
| */ |
| public interface WritableFrameChannel extends Closeable |
| { |
| /** |
| * Writes a frame with an attached partition number. |
| * |
| * May throw an exception if {@link #writabilityFuture()} is unresolved. |
| */ |
| void write(FrameWithPartition frameWithPartition) throws IOException; |
| |
| /** |
| * Writes a frame without an attached partition number. |
| * |
| * May throw an exception if {@link #writabilityFuture()} is unresolved. |
| */ |
| default void write(Frame frame) throws IOException |
| { |
| write(new FrameWithPartition(frame, FrameWithPartition.NO_PARTITION)); |
| } |
| |
| /** |
| * Called prior to {@link #close()} if the writer has failed. Must be followed by a call to {@link #close()}. |
| * |
| * @param cause optional cause of failure. Used by the in-memory channel {@link BlockingQueueFrameChannel.Writable} |
| * to propagate exeptions to downstream processors. Most other channels ignore the provided cause. |
| */ |
| void fail(@Nullable Throwable cause) throws IOException; |
| |
| /** |
| * Finish writing to this channel. |
| * |
| * When this method is called without {@link #fail(Throwable)} having previously been called, the writer is |
| * understood to have completed successfully. |
| * |
| * After calling this method, no additional calls to {@link #write}, {@link #fail(Throwable)}, or this method |
| * are permitted. |
| */ |
| @Override |
| void close() throws IOException; |
| |
| /** |
| * Returns a future that resolves when {@link #write} is able to receive a new frame without blocking or throwing |
| * an exception. The future never resolves to an exception. |
| */ |
| ListenableFuture<?> writabilityFuture(); |
| } |