Query Java Objects
MQL allows you to easily filter, transform and join objects from within your Java code. This example will show you how to filter a List of User objects.
Let’s say your User data base has a List of users like this:
List<User> users = new ArrayList<User>();users.add(new User("Dan", "Diephouse", "MuleSoft", "Engineering"));users.add(new User("Joe", "Sales", "MuleSoft", "Sales"));where your User object has fields along with getters and setters for the fields:
public class User { private String firstName; private String lastName; private String company; private String division; ...}And you would like to filter these users to only include engineers.
First, populate the context:
Map<String,Object> context = new HashMap<String,Object>();context.put("users", users);Then, execute your query to select them:
Collection<User> result = Query.execute("from users where division = 'Engineering'", context);You’ll get a single object back in the collection with the user "Dan Diephouse."
Transformation
Now, let’s say, you want to create an object with a name field which combines firstName and lastName. You can create a new Map of properties by doing this:
Collection<Map> result = Query.execute("from users select new { name = firstName + ' ' + lastName }", context);Each Map in the collection will have a single "name" key with the firstName concatenated to the lastName.