| /** |
| * 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.hadoop.io.serializer; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * <p> |
| * Provides a facility for deserializing objects of type <T> from an |
| * {@link InputStream}. |
| * </p> |
| * |
| * <p> |
| * Deserializers are stateful, but must not buffer the input since |
| * other producers may read from the input between calls to |
| * {@link #deserialize(Object)}. |
| * </p> |
| * @param <T> |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"}) |
| @InterfaceStability.Evolving |
| public interface Deserializer<T> { |
| /** |
| * <p>Prepare the deserializer for reading.</p> |
| */ |
| void open(InputStream in) throws IOException; |
| |
| /** |
| * <p> |
| * Deserialize the next object from the underlying input stream. |
| * If the object <code>t</code> is non-null then this deserializer |
| * <i>may</i> set its internal state to the next object read from the input |
| * stream. Otherwise, if the object <code>t</code> is null a new |
| * deserialized object will be created. |
| * </p> |
| * @return the deserialized object |
| */ |
| T deserialize(T t) throws IOException; |
| |
| /** |
| * <p>Close the underlying input stream and clear up any resources.</p> |
| */ |
| void close() throws IOException; |
| } |