| /* |
| * 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.pig; |
| |
| import java.io.IOException; |
| |
| import org.apache.pig.classification.InterfaceAudience; |
| import org.apache.pig.classification.InterfaceStability; |
| import org.apache.pig.data.WritableByteArray; |
| import org.apache.pig.data.Tuple; |
| |
| /** |
| * The interface is used for the custom mapping of |
| * - a {@link Tuple} to a byte array. The byte array is fed to the stdin |
| * of the streaming process. |
| * - a byte array, received from the stdout of the streaming process, |
| * to a {@link Tuple}. |
| * |
| * This interface is designed to provide a common protocol for data exchange |
| * between Pig runtime and streaming executables. |
| * |
| * Typically, a user implements this interface for a particular type of stream |
| * command and specifies the implementation class in the Pig DEFINE statement. |
| * |
| * @since Pig 0.12 |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public abstract class PigStreamingBase implements PigToStream, StreamToPig { |
| |
| @Override |
| @Deprecated |
| public final byte[] serialize(Tuple t) throws IOException { |
| WritableByteArray data = serializeToBytes(t); |
| if (data.getLength() == data.getData().length) { |
| return data.getData(); |
| } else { |
| byte[] buf = new byte[data.getLength()]; |
| System.arraycopy(data.getData(), 0, buf, 0, data.getLength()); |
| return buf; |
| } |
| } |
| |
| /** |
| * Given a tuple, produce an array of bytes to be passed to the streaming |
| * executable. |
| * @param t Tuple to serialize |
| * @return Serialized form of the tuple |
| * @throws IOException |
| */ |
| public abstract WritableByteArray serializeToBytes(Tuple t) throws IOException; |
| |
| @Override |
| @Deprecated |
| public final Tuple deserialize(byte[] bytes) throws IOException { |
| return deserialize(bytes, 0, bytes.length); |
| } |
| |
| /** |
| * Given a byte array from a streaming executable, produce a tuple. |
| * @param bytes bytes to deserialize. |
| * @param offset the offset in the byte array from which to deserialize. |
| * @param length the number of bytes from the offset of the byte array to deserialize. |
| * @return Data as a Pig Tuple. |
| * @throws IOException |
| */ |
| public abstract Tuple deserialize(byte[] bytes, int offset, int length) throws IOException; |
| |
| /** |
| * This will be called on the front end during planning and not on the back |
| * end during execution. |
| * |
| * @return the {@link LoadCaster} associated with this object, or null if |
| * there is no such LoadCaster. |
| * @throws IOException if there is an exception during LoadCaster |
| */ |
| @Override |
| public abstract LoadCaster getLoadCaster() throws IOException; |
| |
| } |