Question

I’ve been trying to combine the and() and or() methods of the Query interface to create a set of conditions where there are 2 lists of criteria, and at least one from each must be satisfied.

I read this discussion and have been trying to use the Query.and() to combine my two $or clauses.

Essentially, I’m trying to say:

Criteria[] arrayA;
Criteria[] arrayB;

// Programatically populate both arrays

Query q = dao.createQuery().and(
    q.or(arrayA),
    q.or(arrayB)
);

I’m using arrays of criteria because I have to loop through several different inputs to generate the particular criteria I need, and this approach works when I’m just using a single $or, but I can’t get Morphia to generate the query I expect when I try and include both $or clauses in the $and as I explained above. I find that there’s no $and query and the second $or has overwritten the first, just as if I had simply called or() twice.

E.g I expect a query to be generated like this:

{
    "$and": {
    "0": {
        "$or": {
            "0": //Some criteria,
            "1": //Some criteria,
            "2": //Some criteria,
        }
    },
    "1": {
        "$or": {
            "0": //Some other criteria,
            "1": //Some other criteria,
            "2": //Some other criteria,
        }
    }
}

However, I just get a query like this:

{
    "$or": {
        "0": //Some other criteria,
        "1": //Some other criteria,
        "2": //Some other criteria,
    }
}

I can’t see much documentation, but looking at the test case, this seems to be the right way to go about this. Can anyone help shed any light on why this isn’t working as I expect?

(This question was cross-posted to the Morphia mailing list, as I’m not sure which place would get the best response)

Edit 0:

Update: Revisiting this, I have checked out the Morphia test code and every thing runs fine, I’ve been unable to reproduce my issue in the test code.

Therefore, I created a new project to try and get a working example of the query I want. However I encountered the same issue, even with a barebones test project.

The project is mavenised, and the POM is:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>test</groupId>
<artifactId>test</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Test</name>


<dependencies>
    <dependency>
        <groupId>com.google.code.morphia</groupId>
        <artifactId>morphia</artifactId>
        <version>0.99</version>
    </dependency>
</dependencies>
<dependencyManagement>
    <dependencies>
        <!-- Force the use of the latest java mongoDB driver -->
        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongo-java-driver</artifactId>
            <version>2.7.3</version>
        </dependency>
    </dependencies>
</dependencyManagement>

</project>

I have a TestEntity class:

import java.util.Map;

import com.google.code.morphia.annotations.Entity;

@Entity
public class TestEntity {
    Map<String, Integer> map;
}

And finally my test class:

import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

import com.google.code.morphia.Datastore;
import com.google.code.morphia.Morphia;
import com.google.code.morphia.query.Query;
import com.google.code.morphia.query.QueryImpl;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

public class Test {

    static Mongo mongo;
    static Morphia m;
    static Datastore ds;

    static {
        mongo = null;
        try {
            mongo = new Mongo();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (MongoException e) {
            e.printStackTrace();
        }
        m = new Morphia();
        ds = m.createDatastore(mongo, "test");
    }

    public static void main(String[] args) {
        populate();
        query();
    }

    public static void query() {
        Query<TestEntity> q = ds.createQuery(TestEntity.class);

        q.and(q.or(q.criteria("map.field1").exists()),
                q.or(q.criteria("map.field2").exists()));

        Iterable<TestEntity> i = q.fetch();
        for (TestEntity e : i) {
            System.out.println("Result= " + e.map);
        }

        QueryImpl<TestEntity> qi = (QueryImpl<TestEntity>) q;
        System.out    
                .println("Query= " +         qi.prepareCursor().getQuery().toString());
    }

    public static void populate() {
        TestEntity e = new TestEntity();
        Map<String, Integer> map = new HashMap<String, Integer>();
        map.put("field1", 1);
        map.put("field2", 2);
        e.map = map;

        ds.save(e);
    }
}

For me, the above code doesn’t produce the correct $and query, but I can’t see why

Answer 1

Despite Morphia 0.99 including the Query.and(Criteria ...) method, it doesn’t generate the correct query.

Issue 338, which addresses support for explicit $and clauses in queries is targeted at Morphia 0.99.1, which is currently only available as a SNAPSHOT version via Maven.

However, using 0.99.1-SNAPSHOT resolved the issue for us.