| /* |
| * 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.ace.repository.ext; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * Provides an interface for backing up objects. <code>write</code> and <code>read</code> |
| * allow writing and reading of the current version of the object. <code>backup</code> |
| * backs up the object, and <code>restore</code> restores it from a previously backed up |
| * version, if any. There is no way to directly use the backup. |
| */ |
| public interface BackupRepository |
| { |
| |
| /** |
| * Writes the input stream to the current object. |
| * @param data The data to be written. Remember to close this stream, if necessary. |
| * @throws java.io.IOException Will be thrown when (a) the input stream gets closed |
| * unexpectedly, or (b) there is an error writing the data. |
| */ |
| public void write(InputStream data) throws IOException; |
| |
| /** |
| * Reads the input stream from the current object. If there is no current version, |
| * an empty stream will be returned. |
| * @return An input stream, from which can be read. Remember to close it. |
| * @throws java.io.IOException Will be thrown when there is a problem storing the data. |
| */ |
| public InputStream read() throws IOException; |
| |
| /** |
| * Restores a previously backuped version of the object. |
| * @return True when there was a previously backup version which has |
| * now been restored, false otherwise. |
| * @throws java.io.IOException Thrown when the restore process goes bad. |
| */ |
| public boolean restore() throws IOException; |
| |
| /** |
| * Backs up the current version of the object, overwriting a previous |
| * backup, if any. |
| * @return True when there was a current version to be backed up, false |
| * otherwise. |
| * @throws java.io.IOException Thrown when the restore process goes bad. |
| */ |
| public boolean backup() throws IOException; |
| |
| /** |
| * Deletes the whole repository. |
| * |
| * @throws IOException when the repository could not be deleted. |
| */ |
| public void delete() throws IOException; |
| } |