[FSSDK-11161] update: implement CMAB service (#582)

* add: implement CmabDecision class and CmabService interface for CMAB decision handling

* add: implement CmabCacheValue and CmabServiceOptions classes for CMAB service functionality

* add: extend OptimizelyDecideOption with new cache management options and implement DefaultCmabService class

* add: implement DefaultCmabService with decision retrieval and attribute filtering logic

* add: implement fetchDecision method in DefaultCmabService for decision retrieval

* add: enhance getDecision method in DefaultCmabService with caching logic and attribute filtering

* refactor: optimize hashAttributes method using MurmurHash3 and improve null handling

* chore: add Apache License 2.0 header to multiple service classes

* add: implement unit tests for DefaultCmabService with caching and decision retrieval logic

* Empty commit to trigger tests

Author: FarhanAnjum-opti

core-api/src/main/java/com/optimizely/ab/cmab/service/CmabCacheValue.java

@@ -0,0 +1,66 @@
+/**
+ * Copyright 2025, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.optimizely.ab.cmab.service;
+
+import java.util.Objects;
+
+public class CmabCacheValue {
+    private final String attributesHash;
+    private final String variationId;
+    private final String cmabUUID;
+
+    public CmabCacheValue(String attributesHash, String variationId, String cmabUUID) {
+        this.attributesHash = attributesHash;
+        this.variationId = variationId;
+        this.cmabUUID = cmabUUID;
+    }
+
+    public String getAttributesHash() {
+        return attributesHash;
+    }
+
+    public String getVariationId() {
+        return variationId;
+    }
+
+    public String getCmabUuid() {
+        return cmabUUID;
+    }
+
+    @Override
+    public String toString() {
+        return "CmabCacheValue{" +
+            "attributesHash='" + attributesHash + '\'' +
+            ", variationId='" + variationId + '\'' +
+            ", cmabUuid='" + cmabUUID + '\'' +
+            '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        CmabCacheValue that = (CmabCacheValue) o;
+        return Objects.equals(attributesHash, that.attributesHash) &&
+            Objects.equals(variationId, that.variationId) &&
+            Objects.equals(cmabUUID, that.cmabUUID);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributesHash, variationId, cmabUUID);
+    }
+}

core-api/src/main/java/com/optimizely/ab/cmab/service/CmabDecision.java

@@ -0,0 +1,58 @@
+/**
+ * Copyright 2025, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.optimizely.ab.cmab.service;
+
+import java.util.Objects;
+
+public class CmabDecision {
+    private final String variationId;
+    private final String cmabUUID;
+
+    public CmabDecision(String variationId, String cmabUUID) {
+        this.variationId = variationId;
+        this.cmabUUID = cmabUUID;
+    }
+
+    public String getVariationId() {
+        return variationId;
+    }
+
+    public String getCmabUUID() {
+        return cmabUUID;
+    }
+
+    @Override
+    public String toString() {
+        return "CmabDecision{" +
+            "variationId='" + variationId + '\'' +
+            ", cmabUUID='" + cmabUUID + '\'' +
+            '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        CmabDecision that = (CmabDecision) o;
+        return Objects.equals(variationId, that.variationId) &&
+            Objects.equals(cmabUUID, that.cmabUUID);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(variationId, cmabUUID);
+    }
+}

core-api/src/main/java/com/optimizely/ab/cmab/service/CmabService.java

@@ -0,0 +1,39 @@
+/**
+ * Copyright 2025, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.optimizely.ab.cmab.service;
+
+import java.util.List;
+
+import com.optimizely.ab.OptimizelyUserContext;
+import com.optimizely.ab.config.ProjectConfig;
+import com.optimizely.ab.optimizelydecision.OptimizelyDecideOption;
+
+public interface CmabService {
+    /**
+     * Get variation id for the user
+     * @param projectConfig the project configuration
+     * @param userContext   the user context
+     * @param ruleId        the rule identifier
+     * @param options       list of decide options
+     * @return CompletableFuture containing the CMAB decision
+     */
+    CmabDecision getDecision(
+        ProjectConfig projectConfig,
+        OptimizelyUserContext userContext,
+        String ruleId,
+        List<OptimizelyDecideOption> options
+    );
+}

core-api/src/main/java/com/optimizely/ab/cmab/service/CmabServiceOptions.java

@@ -0,0 +1,49 @@
+/**
+ * Copyright 2025, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.optimizely.ab.cmab.service;
+
+import org.slf4j.Logger;
+
+import com.optimizely.ab.cmab.client.CmabClient;
+import com.optimizely.ab.internal.DefaultLRUCache;
+
+public class CmabServiceOptions {
+    private final Logger logger;
+    private final DefaultLRUCache<CmabCacheValue> cmabCache;
+    private final CmabClient cmabClient;
+
+    public CmabServiceOptions(DefaultLRUCache<CmabCacheValue> cmabCache, CmabClient cmabClient) {
+        this(null, cmabCache, cmabClient);
+    }
+
+    public CmabServiceOptions(Logger logger, DefaultLRUCache<CmabCacheValue> cmabCache, CmabClient cmabClient) {
+        this.logger = logger;
+        this.cmabCache = cmabCache;
+        this.cmabClient = cmabClient;
+    }
+
+    public Logger getLogger() {
+        return logger;
+    }
+
+    public DefaultLRUCache<CmabCacheValue> getCmabCache() {
+        return cmabCache;
+    }
+
+    public CmabClient getCmabClient() {
+        return cmabClient;
+    }
+}