Transactional Memory

Simple in-memory transactional database of native objects with persistent log.

Use scripts/test to run tests and scripts/posts-example to run examples.

Example

For the actual code go to examples/PostsExample.java

Define your Domain Models.

public static class Post {
  private String text;
  public String getText() {...}
  public void setText(String text) {...}
}

public static class Posts extends TransactionalMemory {
  public Post get(int i) {...}
  public boolean add(Post post) {...}
  public int size() {...}
}

And use it as plain native Java Objects, changes will be transactional and persistent.

Transactional means that either the whole changes will be applied or nothing (if canceled explicitly or exception thrown).

// Creating collection of Posts.
final Posts posts = new Posts();

// One post will be added.
atomic(new Transaction() { public void run() {
  posts.add(new Post("First post..."));
}});

// Name of the first post will be changed and the second Post will be added,
// transactionally.
atomic(new Transaction() { public void run() {
  posts.get(0).setText("Another name");
  posts.add(new Post("Second post..."));
}});

// Nothing will be changed.
atomic(new Transaction() { public void run() {
  posts.get(0).setText("Yet another name");
  posts.add(new Post("Third post..."));

  // Rolling back changes.
  rollback();
}});

To make operation transactional you need to explain how to roll it back, code below shows how the setText operation implemented.

public static class Post {
  private String text;
  
  public String getText() { return text; }
  
  public void setText(String text) {
    atomize(this, "setText", text).with(this.text);
    this.text = text;
  }
  public void rollbackSetText(String text, String oldText) { this.text = oldText; }
}

Persistence

Not finished yet...

Questions

• Variable visibility in inner and anonymous classes.