Added prereq matcher

Author: chillaq

client/src/main/java/io/split/engine/matchers/PrerequisitesMatcher.java

@@ -0,0 +1,60 @@
+package io.split.engine.matchers;
+
+import io.split.client.dtos.Prerequisites;
+import io.split.engine.evaluator.EvaluationContext;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class PrerequisitesMatcher implements Matcher {
+    private List<Prerequisites> _prerequisites;
+
+    public PrerequisitesMatcher(List<Prerequisites> prerequisites) {
+        _prerequisites = prerequisites;
+    }
+
+    @Override
+    public boolean match(Object matchValue, String bucketingKey, Map<String, Object> attributes, EvaluationContext evaluationContext) {
+        if (matchValue == null) {
+            return false;
+        }
+
+        if (!(matchValue instanceof String)) {
+            return false;
+        }
+        for (Prerequisites prerequisites : _prerequisites) {
+            String treatment = evaluationContext.getEvaluator().evaluateFeature((String) matchValue, bucketingKey, prerequisites.featureFlagName, attributes). treatment;
+            if (!prerequisites.treatments.contains(treatment)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder bldr = new StringBuilder();
+        bldr.append("prerequisites: ");
+        bldr.append(this._prerequisites.stream().map(pr -> pr.featureFlagName + " " + pr.treatments.toString()).map(Object::toString).collect(Collectors.joining(", ")));
+        return bldr.toString();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        PrerequisitesMatcher that = (PrerequisitesMatcher) o;
+
+        return Objects.equals(_prerequisites, that._prerequisites);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = _prerequisites != null ? _prerequisites.hashCode() : 0;
+        result = 31 * result + (_prerequisites != null ? _prerequisites.hashCode() : 0);
+        return result;
+    }
+}

client/src/test/java/io/split/engine/matchers/PrerequisitesMatcherTest.java

@@ -0,0 +1,52 @@
+package io.split.engine.matchers;
+
+import io.split.client.dtos.Prerequisites;
+import io.split.client.utils.Json;
+import io.split.engine.evaluator.EvaluationContext;
+import io.split.engine.evaluator.Evaluator;
+import io.split.engine.evaluator.EvaluatorImp;
+import io.split.storages.RuleBasedSegmentCache;
+import io.split.storages.SegmentCache;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Tests for Prerequisites matcher
+ */
+public class PrerequisitesMatcherTest {
+
+    @Test
+    public void works() {
+        Evaluator evaluator = Mockito.mock(Evaluator.class);
+        EvaluationContext evaluationContext = new EvaluationContext(evaluator, Mockito.mock(SegmentCache.class), Mockito.mock(RuleBasedSegmentCache.class));
+        List<Prerequisites> prerequisites = Arrays.asList(Json.fromJson("{\"n\": \"split1\", \"ts\": [\"on\"]}", Prerequisites.class), Json.fromJson("{\"n\": \"split2\", \"ts\": [\"off\"]}", Prerequisites.class));
+        PrerequisitesMatcher matcher = new PrerequisitesMatcher(prerequisites);
+        Assert.assertEquals("prerequisites: split1 [on], split2 [off]", matcher.toString());
+        PrerequisitesMatcher matcher2 = new PrerequisitesMatcher(prerequisites);
+        Assert.assertTrue(matcher.equals(matcher2));
+        Assert.assertTrue(matcher.hashCode() != 0);
+
+        Mockito.when(evaluator.evaluateFeature("user", "user", "split1", null)).thenReturn(new EvaluatorImp.TreatmentLabelAndChangeNumber("on", ""));
+        Mockito.when(evaluator.evaluateFeature("user", "user", "split2", null)).thenReturn(new EvaluatorImp.TreatmentLabelAndChangeNumber("off", ""));
+        Assert.assertTrue(matcher.match("user", "user", null, evaluationContext));
+
+        Mockito.when(evaluator.evaluateFeature("user", "user", "split2", null)).thenReturn(new EvaluatorImp.TreatmentLabelAndChangeNumber("on", ""));
+        Assert.assertFalse(matcher.match("user", "user", null, evaluationContext));
+    }
+
+    @Test
+    public void invalidParams() {
+        Evaluator evaluator = Mockito.mock(Evaluator.class);
+        EvaluationContext evaluationContext = new EvaluationContext(evaluator, Mockito.mock(SegmentCache.class), Mockito.mock(RuleBasedSegmentCache.class));
+
+        List<Prerequisites> prerequisites = Arrays.asList(Json.fromJson("{\"n\": \"split1\", \"ts\": [\"on\"]}", Prerequisites.class), Json.fromJson("{\"n\": \"split2\", \"ts\": [\"off\"]}", Prerequisites.class));
+        PrerequisitesMatcher matcher = new PrerequisitesMatcher(prerequisites);
+        Mockito.when(evaluator.evaluateFeature("user", "user", "split1", null)).thenReturn(new EvaluatorImp.TreatmentLabelAndChangeNumber("on", ""));
+        Assert.assertFalse(matcher.match(null, null, null, evaluationContext));
+        Assert.assertFalse(matcher.match(123, null, null, evaluationContext));
+    }
+}