Use Maven to add this component as your dependency:
<repositories>
<repository>
<id>persistence-mvn-repo</id>
<url>https://raw.github.com/p2p-sync/persistence/mvn-repo/</url>
<snapshots>
<enabled>true</enabled>
<updatePolicy>always</updatePolicy>
</snapshots>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>org.rmatil.sync.persistence</groupId>
<artifactId>sync-persistence</artifactId>
<version>0.1-SNAPSHOT</version>
</dependency>
</dependencies>This component provides an abstraction for manipulating multiple storage systems. Not only storage adapters to filesystems using a tree-like approach to store data are provided but also adapters to persist data in a distributed hash table (DHT).
A storage adapter abstracts the access to the underlying file system strucutre resp. implementation.
Its specification is provided in IStorageAdapter. Due to these different structures, each interface specifying a type of a storage adapter must also provide
an implementation of IPathElement, defining how values can be retrieved.
Currently Specified Adapters
An ITreeStorageAdapter extends from the general IStorageAdapter and uses the concept of files and directories (implementations could also resolve sym-/hardlinks) to organise persisted data. It is specified in ITreeStorageAdapter. Additionally to the basic CRUD operations (Create, Read, Update, Delete), implementations of this interface must also provide methods to check whether a particular element is a file resp. a directory and accessor to retrieve contents of a directory.
Currently, one implementation of an ITreeStorageAdapter is integrated, specified in ILocalStorageAdapter. It provides the access to a local file system, using Java's io functionality.
Such an adapter is always relative to a particular root directory, path elements are then resolved to this root before
their contents are fetched from the file system
Besides the tree-like storage adapters, an interface for accessing data in distributed hash tables is specified in IDhtStorageAdapter
The IUnsecuredDhtStorageAdapter defines access to data stored in the Distributed Hash Table using only a LocationKey and a ContentKey. Data maintained by such an adapter is not protected against overwrites from other nodes at all.
Its interface is specified in IUnsecuredDhtStorageAdapter
In contrast, an ISecuredDhtStorageAdapter is also responsible to provide a protection mechanism of its stored values by
using a third dimension besides the LocationKey and the ContentKey: the DomainKey. Values stored by using such
an adapter are protected against overwrites from other clients by signing messages. Its interface can be found in ISecuredDhtStorageAdapter
import org.rmatil.sync.persistence.core.tree.ITreeStorageAdapter;
import org.rmatil.sync.persistence.core.tree.TreePathElement;
import org.rmatil.sync.persistence.core.tree.local.LocalStorageAdapter;
import java.nio.file.Paths;
import java.util.List;
// ...
ITreeStorageAdapter treeStorageAdapter = new LocalStorageAdapter(
Paths.get("path/to/root/dir")
);
// get the directory contents at path/to/root/dir/directory
TreePathElement directoryElement = new TreePathElement("directory");
List<TreePathElement> directoryContents = treeStorageAdapter.getDirectoryContents(directoryElement);
// ...
Copyright 2015 rmatil
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.