Sending Your Android App's Requests Using Batch Processing

The Mobile SDK also allows sending requests in batch. This can be much more efficient than sending separate requests. For example, suppose you want to delete ten blog entries in a site’s Blogs portlet at the same time. Instead of making a request for each deletion, you can create a batch of calls and send them all together.

This tutorial shows you how to implement batch processing for your Android app. It’s assumed that you already know how to invoke Liferay services from your Android app. If you don’t, see the tutorial Invoking Liferay Services in Your Android App. Now get ready to whip up a fresh batch of service calls!

Implementing Batch Processing

Making service calls in batch only requires two extra steps over making them one at a time:

• Create a batch session with BatchSessionImpl.
• Make the batch service calls with the invoke method of BatchSessionImpl.

The rest of the steps are the same as making other service calls. You still need a service object, and you still need to call its service methods. As an example, here’s a code snippet from an app that deletes a Blogs portlet’s blog entries synchronously in batch:

import com.liferay.mobile.android.service.BatchSessionImpl;

BatchSessionImpl batch = new BatchSessionImpl(session);
BlogsEntryService service = new BlogsEntryService(batch);

service.deleteEntry(1);
service.deleteEntry(2);
service.deleteEntry(3);

JSONArray jsonArray = batch.invoke();

So what’s going on here? After the import, BatchSessionImpl is used with a pre-existing session to create a batch session. Note that the BatchSessionImpl constructor takes either credentials or a session. Passing a session to the constructor is useful when you already have a Session object and want to reuse the same credentials. After creating the service object, several deleteEntry service calls are created. Since the service object is created with a batch session, these calls aren’t made immediately; they return null instead. The calls aren’t made until issued in batch by calling the invoke() method on the batch session object. It returns a JSONArray containing the results for each service call. Since this example contains three deleteEntry calls, the jsonArray contains three objects. The results are ordered the same as the service calls.

Great! But what if you want to make batch calls asynchronously? No problem! Set the callback as a BatchAsyncTaskCallback instance:

import com.liferay.mobile.android.task.callback.BatchAsyncTaskCallback;

batch.setCallback(new BatchAsyncTaskCallback() {

    public void onFailure(Exception exception) {
    }

    public void onSuccess(JSONArray results) {
        // The result is always a JSONArray 
    }

});

This is similar to the procedure for making asynchronous calls as described in the tutorial Invoking Services Asynchronously from Your Android App. Awesome! Now you know how to make efficient service calls in batch!

Related Topics

Invoking Liferay Services in Your Android App

Invoking Services Asynchronously from Your Android App

Creating iOS Apps that Use Liferay

Service Builder and Services