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Document Store Datastructures (dsds) for Java
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Latest commit bb9f5cd Oct 20, 2012 @basking2 Adding tx.DataStructureFactory which builds proxy objects
that use a TransactionalNodeStore to commit all writes
after a data structure operation.

This allows the user to wrap operations in locks they
are able to coordinate between all clients.



Sdsai-dsds is a Document Store Data Structure Library distributed under the MIT license.

A strong emphasis is placed on minimizing reads and writes to the data store and implementing the Java Collections API where reasonable. Iterators are also an important component of reducing the amount of code required to interact with this data structure when the user wants their data.


When working with document store databases such as Cassandra, picking an evenly distributed key has very desirable properties in that it distributes data evenly across the cluster nodes. This, however, means that iterating over the data or searching the data is much more difficult.

This project implements common data structures using a basic storage API. This allows those data structures to perform their operations on a document storage system while allowing the user to store their data using evenly distributed key values.



The interface org.sdsai.dsds.node.NodeStore is all that must be implemented for the data structures to be used with a new storage system.

Data Structures

The NodeStore interface stores a Node class which is a somewhat abstract representation of a directed graph node. This allows for future implementation of new data structures or algorithms (hopefully) without changes or deep consideration being given to the persistence layer.


o B-Tree o Paged Linked List


  • DirectoryNodeStore - Stores data structures in a file system. One file per Node and one file per user data object.
  • MongoDB - Implemented using the raw MongoDB driver.
  • Riak - Implemented using Jackson 2 to serialize Node and user data.
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