Getting Started:
CRUD Operations with Java

Creating Objects in Riak

The first object that we create is a very basic object with a content type of text/plain. Once that object is created, we create a StoreValue operation that will store the object later on down the line

RiakObject quoteObject = new RiakObject()
        .setContentType("text/plain")
        .setValue(BinaryValue.create("You're dangerous, Maverick"));
Namespace quotesBucket = new Namespace("quotes");
Location quoteObjectLocation = new Location(quotesBucket, "Icemand");
StoreValue storeOp = new StoreValue.Builder(quoteObject)
        .withLocation(quoteObjectLocation)
        .build();

We then use our client object to execute the storage operation:

StoreValue.Response response = client.execute(storeOp);

Reading Objects from Riak

After that, we check to make sure that the stored object has the same value as the object that we created. This requires us to fetch the object by way of a FetchValue operation:

FetchValue fetchOp = new FetchValue.Builder(quoteObjectLocation)
        .build();
RiakObject fetchedObject = client.execute(fetchOp).getValue(RiakObject.class);
assert(fetchedObject.getValue.equals(quoteObject.getValue()));

If the values are equal, as they should be, the Java client will say Success! The object we created and the object we fetched have the same value. If not, then the client will throw an exception.

Updating Objects

Once we’ve read the object back in from Riak, we can update the object and store it back as we did before with the StoreValue object:

fetchedObject.setValue(BinaryValue.create("You can be my wingman any time."));
StoreValue updateOp = new StoreValue.Builder(fetchedObject)
        .withLocation(quoteObjectLocation)
        .build();
StoreValue.Response updateOpResp = client.execute(updateOp);

For more in depth information on updating objects and sibling resolution in Riak, see Updating Objects and Conflict Resolution documentation.

Deleting Objects

Now that we’ve stored and then fetched the object, we can delete it by creating and executing a DeleteValue operation:

DeleteValue deleteOp = new DeleteValue.Builder(quoteObjectLocation)
        .build();
client.execute(deleteOp);

Working With Complex Objects

Since the world is a little more complicated than simple integers and bits of strings, let’s see how we can work with more complex objects. Take for example, this plain old Java object (POJO) that encapsulates some knowledge about a book.

public class Book {
    public String title;
    public String author;
    public String body;
    public String isbn;
    publict Integer copiesOwned;
}

By default, the Java Riak client serializes POJOs as JSON. Let’s create a new Book object to store:

Book mobyDick = new Book();
modyDick.title = "Moby Dick";
mobyDick.author = "Herman Melville";
mobyDick.body = "Call me Ishmael. Some years ago...";
mobyDick.isbn = "11119799723";
mobyDick.copiesOwned = 3;

Now we can store that POJO object just like we stored the more simple object earlier:

Namespace booksBucket = new Namespace("books");
Location mobyDickLocation = new Location(booksBucket, "moby_dick");
StoreValue storeBookOp = new StoreValue.Builder(mobyDick)
        .withLocation(mobyDickLocation)
        .build();
client.execute(storeBookOp);

If we fetch the object (using the same method we showed up above and in TasteOfRiak.java), we should get the following:

{
  "title": "Moby Dick",
  "author": "Herman Melville",
  "body": "Call me Ishmael. Some years ago...",
  "isbn": "1111979723",
  "copiesOwned": 3
}

Since we really like Moby Dick, let’s buy a couple more copies and update the POJO.

To update the POJO, we would use UpdateValue by extending a new BookUpdate class as follows:

public static class BookUpdate extends UpdateValue.Update<Book> {
    private final Book update;
    public BookUpdate(Book update){
        this.update = update;
    }

    @Override
    public Book apply(Book t) {
        if(t == null) {
            t = new Book();
        }

        t.author = update.author;
        t.body = update.body;
        t.copiesOwned = update.copiesOwned;
        t.isbn = update.isbn;
        t.title = update.title;

        return t;
    }
}

Then using the BookUpdate class with our mobyDick object:

mobyDick.copiesOwned = 5;
BookUpdate updatedBook = new BookUpdate(mobyDick);

UpdateValue updateValue = new UpdateValue.Builder(mobyDickLocation)
    .withUpdate(updatedBook).build();
UpdateValue.Response response = client.execute(updateValue);

For more in depth information on updating objects and sibling resolution in Riak, see Updating Objects and Conflict Resolution documention.