Java/Scala API should allow passing feature list as a list of string #12

java/src/main/java/com/logicalclocks/featurestore/FeatureGroup.java

@@ -10,6 +10,7 @@
 import java.io.IOException;
 import java.util.Date;
 import java.util.List;
+import java.util.stream.Collectors;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FeatureGroup {
@@ -57,7 +58,14 @@ public void show(int numRows) throws FeatureStoreException, IOException {
     selectAll().show(numRows);
   }
 
-  public Query select(List<Feature> features) throws FeatureStoreException, IOException {
+  public Query select(List<String> features) throws FeatureStoreException, IOException {
+    // Create a feature object for each string feature given by the user.
+    // For the query building each feature need only the name set.
+    List<Feature> featureObjList  = features.stream().map(Feature::new).collect(Collectors.toList());
+    return selectFeatures(featureObjList);
+  }
+
+  public Query selectFeatures(List<Feature> features) throws FeatureStoreException, IOException {
     return new Query(this, features);
   }
 

java/src/main/java/com/logicalclocks/featurestore/metadata/Query.java

@@ -12,6 +12,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class Query {
 
@@ -38,25 +39,45 @@ public Query join(Query subquery) {
     return join(subquery, JoinType.INNER);
   }
 
-  public Query join(Query subquery, List<Feature> on) {
-    return join(subquery, on, JoinType.INNER);
+  public Query join(Query subquery, List<String> on) {
+    return joinFeatures(subquery, on.stream().map(Feature::new).collect(Collectors.toList()), JoinType.INNER);
   }
 
-  public Query join(Query subquery, List<Feature> leftOn, List<Feature> rightOn) {
-    return join(subquery, leftOn, rightOn, JoinType.INNER);
+  public Query joinFeatures(Query subquery, List<Feature> on) {
+    return joinFeatures(subquery, on, JoinType.INNER);
+  }
+
+  public Query join(Query subquery, List<String> leftOn, List<String> rightOn) {
+    return joinFeatures(subquery, leftOn.stream().map(Feature::new).collect(Collectors.toList()),
+        rightOn.stream().map(Feature::new).collect(Collectors.toList()), JoinType.INNER);
+  }
+
+  public Query joinFeatures(Query subquery, List<Feature> leftOn, List<Feature> rightOn) {
+    return joinFeatures(subquery, leftOn, rightOn, JoinType.INNER);
   }
 
   public Query join(Query subquery, JoinType joinType) {
     joins.add(new Join(subquery, joinType));
     return this;
   }
 
-  public Query join(Query subquery, List<Feature> on, JoinType joinType) {
+  public Query join(Query subquery, List<String> on, JoinType joinType) {
+    joins.add(new Join(subquery, on.stream().map(Feature::new).collect(Collectors.toList()), joinType));
+    return this;
+  }
+
+  public Query joinFeatures(Query subquery, List<Feature> on, JoinType joinType) {
     joins.add(new Join(subquery, on, joinType));
     return this;
   }
 
-  public Query join(Query subquery, List<Feature> leftOn, List<Feature> rightOn, JoinType joinType) {
+  public Query join(Query subquery, List<String> leftOn, List<String> rightOn, JoinType joinType) {
+    joins.add(new Join(subquery, leftOn.stream().map(Feature::new).collect(Collectors.toList()),
+        rightOn.stream().map(Feature::new).collect(Collectors.toList()), joinType));
+    return this;
+  }
+
+  public Query joinFeatures(Query subquery, List<Feature> leftOn, List<Feature> rightOn, JoinType joinType) {
     joins.add(new Join(subquery, leftOn, rightOn, joinType));
     return this;
   }