Assignment Details Part 5 of 7: Ability to unwrap EppoValue to a given type

src/main/java/cloud/eppo/BaseEppoClient.java

@@ -11,10 +11,7 @@
 import cloud.eppo.logging.BanditAssignment;
 import cloud.eppo.logging.BanditLogger;
 import cloud.eppo.ufc.dto.*;
-import cloud.eppo.ufc.dto.adapters.EppoModule;
-import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Timer;
@@ -27,12 +24,7 @@
 
 public class BaseEppoClient {
   private static final Logger log = LoggerFactory.getLogger(BaseEppoClient.class);
-  private final ObjectMapper mapper =
-      new ObjectMapper()
-          .registerModule(EppoModule.eppoModule()); // TODO: is this the best place for this?
-
   protected final ConfigurationRequestor requestor;
-
   private final IConfigurationStore configurationStore;
   private final AssignmentLogger assignmentLogger;
   private final BanditLogger banditLogger;
@@ -311,8 +303,9 @@ private boolean valueTypeMatchesExpected(VariationType expectedType, EppoValue v
       case JSON:
         typeMatch =
             value.isString()
-                // Eppo leaves JSON as a JSON string; to verify it's valid we attempt to parse
-                && parseJsonString(value.stringValue()) != null;
+                // Eppo leaves JSON as a JSON string; to verify it's valid we attempt to parse (via
+                // unwrapping)
+                && value.unwrap(VariationType.JSON) != null;
         break;
       default:
         throw new IllegalArgumentException("Unexpected type for type checking: " + expectedType);
@@ -435,7 +428,7 @@ public JsonNode getJSONAssignment(
               subjectAttributes,
               EppoValue.valueOf(defaultValue.toString()),
               VariationType.JSON);
-      return parseJsonString(value.stringValue());
+      return value.unwrap(VariationType.JSON);
     } catch (Exception e) {
       return throwIfNotGraceful(e, defaultValue);
     }
@@ -481,14 +474,6 @@ public String getJSONStringAssignment(String flagKey, String subjectKey, String
     return this.getJSONStringAssignment(flagKey, subjectKey, new Attributes(), defaultValue);
   }
 
-  private JsonNode parseJsonString(String jsonString) {
-    try {
-      return mapper.readTree(jsonString);
-    } catch (JsonProcessingException e) {
-      return null;
-    }
-  }
-
   public BanditResult getBanditAction(
       String flagKey,
       String subjectKey,

src/main/java/cloud/eppo/api/EppoValue.java

@@ -1,6 +1,9 @@
 package cloud.eppo.api;
 
 import cloud.eppo.ufc.dto.EppoValueType;
+import cloud.eppo.ufc.dto.VariationType;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
@@ -96,6 +99,36 @@ public EppoValueType getType() {
     return type;
   }
 
+  /**
+   * Unwraps this EppoValue to the appropriate Java type based on the variation type.
+   *
+   * @param expectedType the expected variation type
+   * @param <T> the target type (Boolean, Integer, Double, String, or JsonNode)
+   * @return the unwrapped value
+   */
+  @SuppressWarnings("unchecked")
+  public <T> T unwrap(VariationType expectedType) {
+    switch (expectedType) {
+      case BOOLEAN:
+        return (T) Boolean.valueOf(booleanValue());
+      case INTEGER:
+        return (T) Integer.valueOf(Double.valueOf(doubleValue()).intValue());
+      case NUMERIC:
+        return (T) Double.valueOf(doubleValue());
+      case STRING:
+        return (T) stringValue();
+      case JSON:
+        String jsonString = stringValue();
+        try {
+          ObjectMapper mapper = new ObjectMapper();
+          return (T) mapper.readTree(jsonString);
+        } catch (JsonProcessingException e) {
+          return null;
+        }
+    }
+    throw new IllegalArgumentException("Unknown variation type: " + expectedType);
+  }
+
   @Override
   public String toString() {
     switch (this.type) {
@@ -106,7 +139,7 @@ public String toString() {
       case STRING:
         return this.stringValue;
       case ARRAY_OF_STRING:
-        // Android21 back-compatability
+        // Android21 back-compatibility
         return joinStringArray(this.stringArrayValue);
       case NULL:
         return "";

src/test/java/cloud/eppo/api/EppoValueTest.java

@@ -1,7 +1,11 @@
 package cloud.eppo.api;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import cloud.eppo.ufc.dto.VariationType;
+import com.fasterxml.jackson.databind.JsonNode;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -65,4 +69,123 @@ public void testToStringConsistencyAcrossTypes() {
     EppoValue arrayValue = EppoValue.valueOf(array);
     assertEquals("test1, test2", arrayValue.toString());
   }
+
+  @Test
+  public void testUnwrapBoolean() {
+    EppoValue boolValue = EppoValue.valueOf(true);
+    Boolean result = boolValue.unwrap(VariationType.BOOLEAN);
+    assertEquals(Boolean.TRUE, result);
+
+    EppoValue falseValue = EppoValue.valueOf(false);
+    Boolean falseResult = falseValue.unwrap(VariationType.BOOLEAN);
+    assertEquals(Boolean.FALSE, falseResult);
+  }
+
+  @Test
+  public void testUnwrapInteger() {
+    EppoValue numValue = EppoValue.valueOf(42.0);
+    Integer result = numValue.unwrap(VariationType.INTEGER);
+    assertEquals(Integer.valueOf(42), result);
+
+    EppoValue negativeValue = EppoValue.valueOf(-17.0);
+    Integer negativeResult = negativeValue.unwrap(VariationType.INTEGER);
+    assertEquals(Integer.valueOf(-17), negativeResult);
+  }
+
+  @Test
+  public void testUnwrapNumeric() {
+    EppoValue numValue = EppoValue.valueOf(123.456);
+    Double result = numValue.unwrap(VariationType.NUMERIC);
+    assertEquals(Double.valueOf(123.456), result);
+
+    EppoValue intValue = EppoValue.valueOf(100.0);
+    Double intResult = intValue.unwrap(VariationType.NUMERIC);
+    assertEquals(Double.valueOf(100.0), intResult);
+  }
+
+  @Test
+  public void testUnwrapString() {
+    EppoValue strValue = EppoValue.valueOf("hello world");
+    String result = strValue.unwrap(VariationType.STRING);
+    assertEquals("hello world", result);
+
+    EppoValue emptyValue = EppoValue.valueOf("");
+    String emptyResult = emptyValue.unwrap(VariationType.STRING);
+    assertEquals("", emptyResult);
+  }
+
+  @Test
+  public void testUnwrapJsonValid() {
+    String jsonString = "{\"foo\":\"bar\",\"count\":42}";
+    EppoValue jsonValue = EppoValue.valueOf(jsonString);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isObject());
+    assertEquals("bar", result.get("foo").asText());
+    assertEquals(42, result.get("count").asInt());
+  }
+
+  @Test
+  public void testUnwrapJsonArray() {
+    String jsonArrayString = "[1,2,3,4,5]";
+    EppoValue jsonValue = EppoValue.valueOf(jsonArrayString);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isArray());
+    assertEquals(5, result.size());
+    assertEquals(1, result.get(0).asInt());
+    assertEquals(5, result.get(4).asInt());
+  }
+
+  @Test
+  public void testUnwrapJsonWithSpecialCharacters() {
+    String jsonString = "{\"a\":\"kümmert\",\"b\":\"schön\"}";
+    EppoValue jsonValue = EppoValue.valueOf(jsonString);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isObject());
+    assertEquals("kümmert", result.get("a").asText());
+    assertEquals("schön", result.get("b").asText());
+  }
+
+  @Test
+  public void testUnwrapJsonWithEmojis() {
+    String jsonString = "{\"a\":\"🤗\",\"b\":\"🌸\"}";
+    EppoValue jsonValue = EppoValue.valueOf(jsonString);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isObject());
+    assertEquals("🤗", result.get("a").asText());
+    assertEquals("🌸", result.get("b").asText());
+  }
+
+  @Test
+  public void testUnwrapJsonWithWhitespace() {
+    String jsonString = "{ \"key\": \"value\", \"number\": 123 }";
+    EppoValue jsonValue = EppoValue.valueOf(jsonString);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isObject());
+    assertEquals("value", result.get("key").asText());
+    assertEquals(123, result.get("number").asInt());
+  }
+
+  @Test
+  public void testUnwrapJsonInvalid() {
+    String invalidJson = "not valid json {";
+    EppoValue jsonValue = EppoValue.valueOf(invalidJson);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertNull(result, "Invalid JSON should return null");
+  }
+
+  @Test
+  public void testUnwrapJsonEmpty() {
+    String emptyJson = "{}";
+    EppoValue jsonValue = EppoValue.valueOf(emptyJson);
+    JsonNode result = jsonValue.unwrap(VariationType.JSON);
+
+    assertTrue(result.isObject());
+    assertEquals(0, result.size());
+  }
 }