Merge pull request #78 from m-chrzan/qurnik

Run queries with Qurnik

10 files changed, 403 insertions, 36 deletions

diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/QurnikMessage.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/QurnikMessage.java
new file mode 100644
index 0000000..0161a37
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/QurnikMessage.java
@@ -0,0 +1,25 @@
+package pl.edu.mimuw.cloudatlas.agent.messages;
+
+import pl.edu.mimuw.cloudatlas.agent.modules.Module;
+import pl.edu.mimuw.cloudatlas.agent.modules.ModuleType;
+
+public abstract class QurnikMessage extends AgentMessage {
+    public enum Type {
+        RUN_QUERIES
+    }
+
+    private Type type;
+
+    public QurnikMessage(String messageId, long timestamp, Type type) {
+        super(messageId, ModuleType.QUERY, timestamp);
+        this.type = type;
+    }
+
+    public Type getType() {
+        return type;
+    }
+
+    public void callMe(Module module) throws InterruptedException, Module.InvalidMessageType {
+        module.handleTyped(this);
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/RunQueriesMessage.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/RunQueriesMessage.java
new file mode 100644
index 0000000..35f7819
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/messages/RunQueriesMessage.java
@@ -0,0 +1,9 @@
+package pl.edu.mimuw.cloudatlas.agent.messages;
+
+import pl.edu.mimuw.cloudatlas.agent.modules.ModuleType;
+
+public class RunQueriesMessage extends QurnikMessage {
+    public RunQueriesMessage(String messageId, long timestamp) {
+        super(messageId, timestamp, Type.RUN_QUERIES);
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Module.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Module.java
index d0bf083..ba5e1d1 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Module.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Module.java
@@ -3,6 +3,7 @@ package pl.edu.mimuw.cloudatlas.agent.modules;
 import pl.edu.mimuw.cloudatlas.agent.Executor;
 import pl.edu.mimuw.cloudatlas.agent.messages.AgentMessage;
 import pl.edu.mimuw.cloudatlas.agent.messages.TimerSchedulerMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.QurnikMessage;
 import pl.edu.mimuw.cloudatlas.agent.messages.ResponseMessage;
 import pl.edu.mimuw.cloudatlas.agent.messages.RMIMessage;
 import pl.edu.mimuw.cloudatlas.agent.messages.StanikMessage;
@@ -32,6 +33,10 @@ public abstract class Module {
         throw new InvalidMessageType("Got a TimerSchedulerMessage in module " + moduleType.toString());
     }
 
+    public void handleTyped(QurnikMessage message) throws InterruptedException, InvalidMessageType {
+        throw new InvalidMessageType("Got a QurnikMessage in module " + moduleType.toString());
+    }
+
     public void handleTyped(RMIMessage message) throws InterruptedException, InvalidMessageType {
         throw new InvalidMessageType("Got an RMIMessage in module " + moduleType.toString());
     }
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Qurnik.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Qurnik.java
new file mode 100644
index 0000000..9b7268a
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Qurnik.java
@@ -0,0 +1,105 @@
+package pl.edu.mimuw.cloudatlas.agent.modules;
+
+import java.util.List;
+import java.util.LinkedList;
+import java.util.Map.Entry;
+
+import pl.edu.mimuw.cloudatlas.agent.messages.GetStateMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.QurnikMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.ResponseMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.RunQueriesMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.StateMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.UpdateAttributesMessage;
+import pl.edu.mimuw.cloudatlas.interpreter.Interpreter;
+import pl.edu.mimuw.cloudatlas.interpreter.InterpreterException;
+import pl.edu.mimuw.cloudatlas.interpreter.QueryResult;
+import pl.edu.mimuw.cloudatlas.model.Attribute;
+import pl.edu.mimuw.cloudatlas.model.AttributesMap;
+import pl.edu.mimuw.cloudatlas.model.AttributesUtil;
+import pl.edu.mimuw.cloudatlas.model.PathName;
+import pl.edu.mimuw.cloudatlas.model.TypePrimitive;
+import pl.edu.mimuw.cloudatlas.model.Value;
+import pl.edu.mimuw.cloudatlas.model.ValueQuery;
+import pl.edu.mimuw.cloudatlas.model.ValueString;
+import pl.edu.mimuw.cloudatlas.model.ValueTime;
+import pl.edu.mimuw.cloudatlas.model.ValueUtils;
+import pl.edu.mimuw.cloudatlas.model.ZMI;
+
+public class Qurnik extends Module {
+    public Qurnik() {
+        super(ModuleType.QUERY);
+    }
+
+    @Override
+    public void handleTyped(QurnikMessage message) throws InterruptedException, InvalidMessageType {
+        switch (message.getType()) {
+            case RUN_QUERIES:
+                handleRunQueries((RunQueriesMessage) message);
+                break;
+            default:
+                throw new InvalidMessageType("This type of message cannot be handled by Qurnik");
+        }
+    }
+
+    @Override
+    public void handleTyped(ResponseMessage message) throws InterruptedException, InvalidMessageType {
+        switch (message.getType()) {
+            case STATE:
+                runQueriesOnState((StateMessage) message);
+                break;
+            default:
+                throw new InvalidMessageType("This type of message cannot be handled by Qurnik");
+        }
+    }
+
+    private void handleRunQueries(RunQueriesMessage message) throws InterruptedException {
+        GetStateMessage getStateMessage = new GetStateMessage("", 0, ModuleType.QUERY, 0);
+        sendMessage(getStateMessage);
+    }
+
+    private void runQueriesOnState(StateMessage message) throws InterruptedException {
+        List<ValueQuery> queries = new LinkedList();
+        for (Entry<ValueQuery, ValueTime> timestampedQuery : message.getQueries().values()) {
+            queries.add(timestampedQuery.getKey());
+        }
+        executeAllQueries(message.getZMI(), queries, PathName.ROOT);
+    }
+
+    private void executeAllQueries(ZMI zmi, List<ValueQuery> queries, PathName currentPath) throws InterruptedException {
+        if(!zmi.getSons().isEmpty()) {
+            for(ZMI son : zmi.getSons()) {
+                Value sonName = son.getAttributes().getOrNull("name");
+                if (ValueUtils.valueNonNullOfType(sonName, TypePrimitive.STRING)) {
+                    String sonNameString = ((ValueString) sonName).getValue();
+                    executeAllQueries(son, queries, currentPath.levelDown(sonNameString));
+                } else {
+                    System.out.println("ERROR: zone without a name attribute found while executing queries");
+                }
+            }
+
+            Interpreter interpreter = new Interpreter(zmi);
+            AttributesMap newAttributes = new AttributesMap();
+            for (ValueQuery query : queries) {
+                try {
+                    List<QueryResult> result = interpreter.interpretProgram(query.getQuery());
+                    for(QueryResult r : result) {
+                        newAttributes.addOrChange(r.getName(), r.getValue());
+                    }
+                } catch(InterpreterException exception) {
+                    System.out.println("ERROR: thrown while running interpreter: " + exception.getMessage());
+                }
+            }
+
+            if (!currentPath.toString().equals("/")) {
+                newAttributes.add("name", new ValueString(currentPath.getSingletonName()));
+            }
+            long currentTime = System.currentTimeMillis();
+            newAttributes.add("timestamp", new ValueTime(currentTime));
+
+            AttributesUtil.transferAttributes(newAttributes, zmi.getAttributes());
+
+            UpdateAttributesMessage message = new UpdateAttributesMessage("", currentTime, currentPath.toString(), newAttributes);
+            sendMessage(message);
+        }
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
index e8721b3..4694219 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
@@ -12,6 +12,7 @@ import pl.edu.mimuw.cloudatlas.agent.messages.UpdateAttributesMessage;
 import pl.edu.mimuw.cloudatlas.agent.messages.UpdateQueriesMessage;
 import pl.edu.mimuw.cloudatlas.model.Attribute;
 import pl.edu.mimuw.cloudatlas.model.AttributesMap;
+import pl.edu.mimuw.cloudatlas.model.AttributesUtil;
 import pl.edu.mimuw.cloudatlas.model.PathName;
 import pl.edu.mimuw.cloudatlas.model.Type;
 import pl.edu.mimuw.cloudatlas.model.TypePrimitive;
@@ -67,7 +68,7 @@ public class Stanik extends Module {
             ZMI zone = hierarchy.findDescendant(message.getPathName());
             AttributesMap attributes = zone.getAttributes();
             if (valueLower(attributes.get("timestamp"), message.getAttributes().get("timestamp"))) {
-                transferAttributes(message.getAttributes(), attributes);
+                AttributesUtil.transferAttributes(message.getAttributes(), attributes);
             } else {
                 System.out.println("DEBUG: not applying update with older attributes");
             }
@@ -127,21 +128,6 @@ public class Stanik extends Module {
         return value != null && !value.isNull() && value.getType().isCompatible(type);
     }
 
-    private void transferAttributes(AttributesMap fromAttributes, AttributesMap toAttributes) {
-        Iterator<Entry<Attribute, Value>> iterator = toAttributes.iterator();
-        while (iterator.hasNext()) {
-            Entry<Attribute, Value> entry = iterator.next();
-            Attribute attribute = entry.getKey();
-            Value newValue = fromAttributes.getOrNull(attribute);
-            if (newValue == null) {
-                iterator.remove();
-            }
-        }
-        for (Entry<Attribute, Value> entry : fromAttributes) {
-            toAttributes.addOrChange(entry.getKey(), entry.getValue());
-        }
-    }
-
     private void addMissingZones(PathName path) {
         try {
             if (!hierarchy.descendantExists(path)) {
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/model/AttributesUtil.java b/src/main/java/pl/edu/mimuw/cloudatlas/model/AttributesUtil.java
new file mode 100644
index 0000000..cd2ae91
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/model/AttributesUtil.java
@@ -0,0 +1,21 @@
+package pl.edu.mimuw.cloudatlas.model;
+
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+public class AttributesUtil {
+    public static void transferAttributes(AttributesMap fromAttributes, AttributesMap toAttributes) {
+        Iterator<Entry<Attribute, Value>> iterator = toAttributes.iterator();
+        while (iterator.hasNext()) {
+            Entry<Attribute, Value> entry = iterator.next();
+            Attribute attribute = entry.getKey();
+            Value newValue = fromAttributes.getOrNull(attribute);
+            if (newValue == null) {
+                iterator.remove();
+            }
+        }
+        for (Entry<Attribute, Value> entry : fromAttributes) {
+            toAttributes.addOrChange(entry.getKey(), entry.getValue());
+        }
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueUtils.java b/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueUtils.java
new file mode 100644
index 0000000..01a45b5
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueUtils.java
@@ -0,0 +1,7 @@
+package pl.edu.mimuw.cloudatlas.model;
+
+public class ValueUtils {
+    public static boolean valueNonNullOfType(Value value, Type type) {
+        return value != null && !value.isNull() && value.getType().isCompatible(type);
+    }
+}
diff --git a/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/QurnikTest.java b/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/QurnikTest.java
new file mode 100644
index 0000000..0c10092
--- /dev/null
+++ b/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/QurnikTest.java
@@ -0,0 +1,203 @@
+package pl.edu.mimuw.cloudatlas.agent.modules;
+
+import java.util.AbstractMap.SimpleImmutableEntry;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import pl.edu.mimuw.cloudatlas.agent.messages.AgentMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.GetStateMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.RunQueriesMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.StanikMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.StateMessage;
+import pl.edu.mimuw.cloudatlas.agent.messages.UpdateAttributesMessage;
+import pl.edu.mimuw.cloudatlas.agent.MockExecutor;
+import pl.edu.mimuw.cloudatlas.model.Attribute;
+import pl.edu.mimuw.cloudatlas.model.AttributesMap;
+import pl.edu.mimuw.cloudatlas.model.TestUtil;
+import pl.edu.mimuw.cloudatlas.model.ValueInt;
+import pl.edu.mimuw.cloudatlas.model.ValueQuery;
+import pl.edu.mimuw.cloudatlas.model.ValueString;
+import pl.edu.mimuw.cloudatlas.model.ValueTime;
+import pl.edu.mimuw.cloudatlas.model.ZMI;
+
+import org.junit.Before;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class QurnikTest {
+    private Qurnik qurnik;
+    private MockExecutor executor;
+
+    @Before
+    public void setupLocals() {
+        qurnik = new Qurnik();
+        executor = new MockExecutor(qurnik);
+    }
+
+    @Test
+    public void runQueriesRequestsState() throws Exception {
+        RunQueriesMessage message = new RunQueriesMessage("", 0);
+        qurnik.handleTyped(message);
+        AgentMessage receivedMessage = (AgentMessage) executor.messagesToPass.take();
+        assertEquals(ModuleType.STATE, receivedMessage.getDestinationModule());
+        StanikMessage stanikMessage = (StanikMessage) receivedMessage;
+        assertEquals(StanikMessage.Type.GET_STATE, stanikMessage.getType());
+        GetStateMessage getStateMessage = (GetStateMessage) stanikMessage;
+        assertEquals(ModuleType.QUERY, getStateMessage.getRequestingModule());
+    }
+
+    @Test
+    public void simpleQuery() throws Exception {
+        ZMI root = new ZMI();
+        ZMI son = new ZMI(root);
+        root.addSon(son);
+        AttributesMap sonAttributes = new AttributesMap();
+        sonAttributes.add("name", new ValueString("son"));
+        Map<Attribute, Entry<ValueQuery, ValueTime>> queries = new HashMap();
+        queries.put(
+                new Attribute("&query"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT 1 AS one"),
+                    new ValueTime(0l)
+                )
+        );
+        StateMessage message = new StateMessage("", ModuleType.QUERY, 0, 0, root, queries);
+        long timeBefore = System.currentTimeMillis();
+        qurnik.handleTyped(message);
+        long timeAfter = System.currentTimeMillis();
+
+        assertEquals(1, executor.messagesToPass.size());
+        AgentMessage receivedMessage = (AgentMessage) executor.messagesToPass.take();
+        assertEquals(ModuleType.STATE, receivedMessage.getDestinationModule());
+        StanikMessage stanikMessage = (StanikMessage) receivedMessage;
+        assertEquals(StanikMessage.Type.UPDATE_ATTRIBUTES, stanikMessage.getType());
+        UpdateAttributesMessage updateAttributesMessage = (UpdateAttributesMessage) stanikMessage;
+        assertEquals("/", updateAttributesMessage.getPathName());
+        AttributesMap updatedAttributes = updateAttributesMessage.getAttributes();
+        assertEquals(2, TestUtil.iterableSize(updatedAttributes));
+        assertEquals(new ValueInt(1l), updatedAttributes.getOrNull("one"));
+        long timestamp = ((ValueTime) updatedAttributes.getOrNull("timestamp")).getValue();
+        assertTrue(timeBefore <= timestamp);
+        assertTrue(timestamp <= timeAfter);
+    }
+
+    private ZMI setupSampleHierarchy() {
+        ZMI root = new ZMI();
+
+        ZMI uw = new ZMI(root);
+        root.addSon(uw);
+        ZMI pw = new ZMI(root);
+        root.addSon(pw);
+
+        ZMI uw1 = new ZMI(uw);
+        uw.addSon(uw1);
+        ZMI uw2 = new ZMI(uw);
+        uw.addSon(uw2);
+
+        AttributesMap uwAttributes = uw.getAttributes();
+        uwAttributes.add("name", new ValueString("uw"));
+
+        AttributesMap pwAttributes = pw.getAttributes();
+        pwAttributes.add("name", new ValueString("pw"));
+        pwAttributes.add("x", new ValueInt(42l));
+        pwAttributes.add("y", new ValueInt(250l));
+        pwAttributes.add("z", new ValueInt(5l));
+
+        AttributesMap uw1Attributes = uw1.getAttributes();
+        uw1Attributes.add("name", new ValueString("uw1"));
+        uw1Attributes.add("x", new ValueInt(12l));
+        uw1Attributes.add("y", new ValueInt(100l));
+        uw1Attributes.add("a", new ValueInt(123l));
+
+        AttributesMap uw2Attributes = uw2.getAttributes();
+        uw2Attributes.add("name", new ValueString("uw2"));
+        uw2Attributes.add("x", new ValueInt(13l));
+        uw2Attributes.add("a", new ValueInt(134l));
+        uw2Attributes.add("b", new ValueInt(777l));
+
+        return root;
+    }
+
+    public Map<Attribute, Entry<ValueQuery, ValueTime>> setupSampleQueries() throws Exception {
+        Map<Attribute, Entry<ValueQuery, ValueTime>> queries = new HashMap();
+
+        queries.put(
+                new Attribute("&query1"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT sum(x) AS x"),
+                    new ValueTime(0l)
+                )
+        );
+        queries.put(
+                new Attribute("&query2"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT min(y) AS y"),
+                    new ValueTime(0l)
+                )
+        );
+        queries.put(
+                new Attribute("&query3"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT max(z) AS z"),
+                    new ValueTime(0l)
+                )
+        );
+        queries.put(
+                new Attribute("&query4"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT sum(a + 1) AS a"),
+                    new ValueTime(0l)
+                )
+        );
+        queries.put(
+                new Attribute("&query5"),
+                new SimpleImmutableEntry(
+                    new ValueQuery("SELECT sum(2 * b) AS b"),
+                    new ValueTime(0l)
+                )
+        );
+
+        return queries;
+    }
+
+    @Test
+    public void multipleQueries() throws Exception {
+        ZMI root = setupSampleHierarchy();
+
+        Map<Attribute, Entry<ValueQuery, ValueTime>> queries = setupSampleQueries();
+        StateMessage message = new StateMessage("", ModuleType.QUERY, 0, 0, root, queries);
+        long timeBefore = System.currentTimeMillis();
+        qurnik.handleTyped(message);
+        long timeAfter = System.currentTimeMillis();
+
+        assertEquals(2, executor.messagesToPass.size());
+
+        UpdateAttributesMessage message1 = (UpdateAttributesMessage) executor.messagesToPass.take();
+        assertEquals("/uw", message1.getPathName());
+        AttributesMap attributes1 = message1.getAttributes();
+        assertEquals(6, TestUtil.iterableSize(attributes1));
+        assertEquals(new ValueString("uw"), attributes1.getOrNull("name"));
+        assertEquals(new ValueInt(25l), attributes1.getOrNull("x"));
+        assertEquals(new ValueInt(100l), attributes1.getOrNull("y"));
+        assertEquals(new ValueInt(259l), attributes1.getOrNull("a"));
+        assertEquals(new ValueInt(1554l), attributes1.getOrNull("b"));
+        long timestamp1 = ((ValueTime) attributes1.getOrNull("timestamp")).getValue();
+        assertTrue(timeBefore <= timestamp1);
+        assertTrue(timestamp1 <= timeAfter);
+
+        UpdateAttributesMessage message2 = (UpdateAttributesMessage) executor.messagesToPass.take();
+        assertEquals("/", message2.getPathName());
+        AttributesMap attributes2 = message2.getAttributes();
+        System.out.println("got attributes " + attributes2.toString());
+        assertEquals(6, TestUtil.iterableSize(attributes2));
+        assertEquals(new ValueInt(67l), attributes2.getOrNull("x"));
+        assertEquals(new ValueInt(100l), attributes2.getOrNull("y"));
+        assertEquals(new ValueInt(5l), attributes2.getOrNull("z"));
+        assertEquals(new ValueInt(260l), attributes2.getOrNull("a"));
+        assertEquals(new ValueInt(3108l), attributes2.getOrNull("b"));
+        long timestamp2 = ((ValueTime) attributes2.getOrNull("timestamp")).getValue();
+        assertTrue(timeBefore <= timestamp2);
+        assertTrue(timestamp2 <= timeAfter);
+    }
+}
diff --git a/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/StanikTest.java b/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/StanikTest.java
index aeaf19f..8958472 100644
--- a/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/StanikTest.java
+++ b/src/test/java/pl/edu/mimuw/cloudatlas/agent/modules/StanikTest.java
@@ -1,7 +1,5 @@
 package pl.edu.mimuw.cloudatlas.agent.modules;
 
-import java.util.Iterator;
-import java.util.List;
 import java.util.AbstractMap.SimpleImmutableEntry;
 import java.util.HashMap;
 import java.util.Map;
@@ -16,6 +14,7 @@ import pl.edu.mimuw.cloudatlas.agent.messages.UpdateQueriesMessage;
 import pl.edu.mimuw.cloudatlas.agent.MockExecutor;
 import pl.edu.mimuw.cloudatlas.model.Attribute;
 import pl.edu.mimuw.cloudatlas.model.AttributesMap;
+import pl.edu.mimuw.cloudatlas.model.TestUtil;
 import pl.edu.mimuw.cloudatlas.model.Value;
 import pl.edu.mimuw.cloudatlas.model.ValueInt;
 import pl.edu.mimuw.cloudatlas.model.ValueQuery;
@@ -32,7 +31,7 @@ public class StanikTest {
     private MockExecutor executor;
 
     @Before
-    public void setupEventBus() {
+    public void setupLocals() {
         stanik = new Stanik();
         executor = new MockExecutor(stanik);
     }
@@ -50,9 +49,9 @@ public class StanikTest {
         ZMI zmi = stateMessage.getZMI();
         assertNull(zmi.getFather());
         assertTrue(zmi.getSons().isEmpty());
-        assertEquals(1, iterableSize(zmi.getAttributes()));
+        assertEquals(1, TestUtil.iterableSize(zmi.getAttributes()));
         Map<Attribute, Entry<ValueQuery, ValueTime>> queries = stateMessage.getQueries();
-        assertEquals(0, iterableSize(queries.keySet()));
+        assertEquals(0, TestUtil.iterableSize(queries.keySet()));
     }
 
     @Test
@@ -81,7 +80,7 @@ public class StanikTest {
         UpdateAttributesMessage message = new UpdateAttributesMessage("test_msg", 0, "/", attributes);
         stanik.handleTyped(message);
         AttributesMap actualAttributes = stanik.getHierarchy().getAttributes();
-        assertEquals(3, iterableSize(actualAttributes));
+        assertEquals(3, TestUtil.iterableSize(actualAttributes));
         assertEquals(new ValueInt(1337l), actualAttributes.get("foo"));
         assertEquals(new ValueString("baz"), actualAttributes.get("bar"));
         assertEquals(new ValueTime("2012/12/21 04:20:00.000"), actualAttributes.getOrNull("timestamp"));
@@ -97,7 +96,7 @@ public class StanikTest {
         UpdateAttributesMessage message = new UpdateAttributesMessage("test_msg", 0, "/new", attributes);
         stanik.handleTyped(message);
         AttributesMap actualAttributes = stanik.getHierarchy().findDescendant("/new").getAttributes();
-        assertEquals(4, iterableSize(actualAttributes));
+        assertEquals(4, TestUtil.iterableSize(actualAttributes));
         assertEquals(new ValueInt(1337l), actualAttributes.getOrNull("foo"));
         assertEquals(new ValueString("baz"), actualAttributes.getOrNull("bar"));
         assertEquals(new ValueString("new"), actualAttributes.getOrNull("name"));
@@ -120,7 +119,7 @@ public class StanikTest {
         stanik.handleTyped(newMessage);
 
         AttributesMap actualAttributes = stanik.getHierarchy().getAttributes();
-        assertEquals(2, iterableSize(actualAttributes));
+        assertEquals(2, TestUtil.iterableSize(actualAttributes));
         assertEquals(new ValueInt(1338l), actualAttributes.getOrNull("foo"));
         assertEquals(new ValueTime("2012/12/21 04:20:42.000"), actualAttributes.getOrNull("timestamp"));
     }
@@ -140,7 +139,7 @@ public class StanikTest {
         stanik.handleTyped(newMessage);
 
         AttributesMap actualAttributes = stanik.getHierarchy().getAttributes();
-        assertEquals(2, iterableSize(actualAttributes));
+        assertEquals(2, TestUtil.iterableSize(actualAttributes));
         assertEquals(new ValueInt(1337l), actualAttributes.getOrNull("foo"));
         assertEquals(new ValueTime("2012/12/21 04:20:00.000"), actualAttributes.getOrNull("timestamp"));
     }
@@ -153,7 +152,7 @@ public class StanikTest {
         stanik.handleTyped(message);
 
         HashMap<Attribute, Entry<ValueQuery, ValueTime>> actualQueries = stanik.getQueries();
-        assertEquals(1, iterableSize(actualQueries.keySet()));
+        assertEquals(1, TestUtil.iterableSize(actualQueries.keySet()));
         assertTrue(actualQueries.containsKey(new Attribute("&query")));
         Entry<ValueQuery, ValueTime> timestampedQuery = actualQueries.get(new Attribute("&query"));
         assertEquals(new ValueTime(42l), timestampedQuery.getValue());
@@ -177,7 +176,7 @@ public class StanikTest {
         stanik.handleTyped(otherMessage);
 
         HashMap<Attribute, Entry<ValueQuery, ValueTime>> actualQueries = stanik.getQueries();
-        assertEquals(4, iterableSize(actualQueries.keySet()));
+        assertEquals(4, TestUtil.iterableSize(actualQueries.keySet()));
         assertTrue(actualQueries.containsKey(new Attribute("&query1")));
         assertTrue(actualQueries.containsKey(new Attribute("&query2")));
         assertTrue(actualQueries.containsKey(new Attribute("&query3")));
@@ -199,13 +198,4 @@ public class StanikTest {
         assertEquals(new ValueTime(43l), timestampedQuery4.getValue());
         assertEquals(new ValueQuery("SELECT 1000 AS foo"), timestampedQuery4.getKey());
     }
-
-    public <T> int iterableSize(Iterable<T> iterable) {
-        int count = 0;
-        for (T attribute : iterable) {
-            count++;
-        }
-
-        return count;
-    }
 }
diff --git a/src/test/java/pl/edu/mimuw/cloudatlas/model/TestUtil.java b/src/test/java/pl/edu/mimuw/cloudatlas/model/TestUtil.java
new file mode 100644
index 0000000..ed633d7
--- /dev/null
+++ b/src/test/java/pl/edu/mimuw/cloudatlas/model/TestUtil.java
@@ -0,0 +1,16 @@
+package pl.edu.mimuw.cloudatlas.model;
+
+public class TestUtil {
+    public static boolean valueLower(Value a, Value b) {
+        return ((ValueBoolean) a.isLowerThan(b)).getValue();
+    }
+
+    public static <T> int iterableSize(Iterable<T> iterable) {
+        int count = 0;
+        for (T attribute : iterable) {
+            count++;
+        }
+
+        return count;
+    }
+}