ISSUE-1026 Add support for @subselect (#1038)

* Manager transacton manually

* Add readonly

* some rework

* use getTimeDimension()

* change exception

* ISSUE-1026 Add support for @subselect

* Address comments

elide-datastore/elide-datastore-aggregation/src/main/java/com/yahoo/elide/datastores/aggregation/queryengines/sql/SQLQueryEngine.java

@@ -30,7 +30,6 @@
 import com.yahoo.elide.utils.coerce.CoerceUtil;
 
 import com.google.common.base.Preconditions;
-
 import org.hibernate.jpa.QueryHints;
 
 import lombok.Getter;
@@ -48,7 +47,6 @@
 import javax.persistence.EntityManager;
 import javax.persistence.EntityManagerFactory;
 import javax.persistence.EntityTransaction;
-import javax.persistence.Table;
 
 /**
  * QueryEngine for SQL backed stores.
@@ -181,7 +179,7 @@ protected SQLQuery toSQL(Query query, SQLSchema schema) {
                     (predicate) -> { return generateHavingClauseColumnReference(predicate, query); }));
         }
 
-        if (! query.getDimensions().isEmpty())  {
+        if (!query.getDimensions().isEmpty())  {
             builder.groupByClause(extractGroupBy(query));
 
             joinPredicates.addAll(extractPathElements(query
@@ -298,25 +296,20 @@ private String extractJoin(Path.PathElement pathElement) {
         //TODO - support joins where either side owns the relationship.
         //TODO - Support INNER and RIGHT joins.
         //TODO - Support toMany joins.
-        String relationshipName = pathElement.getFieldName();
-        Class<?> relationshipClass = pathElement.getFieldType();
-        String relationshipAlias = FilterPredicate.getTypeAlias(relationshipClass);
         Class<?> entityClass = pathElement.getType();
         String entityAlias = FilterPredicate.getTypeAlias(entityClass);
 
-        Table tableAnnotation = dictionary.getAnnotation(relationshipClass, Table.class);
-
-        String relationshipTableName = (tableAnnotation == null)
-                ? dictionary.getJsonAliasFor(relationshipClass)
-                : tableAnnotation.name();
-
+        Class<?> relationshipClass = pathElement.getFieldType();
+        String relationshipAlias = FilterPredicate.getTypeAlias(relationshipClass);
+        String relationshipName = pathElement.getFieldName();
         String relationshipIdField = getColumnName(relationshipClass, dictionary.getIdFieldName(relationshipClass));
+        String relationshipColumnName = getColumnName(entityClass, relationshipName);
 
         return String.format("LEFT JOIN %s AS %s ON %s.%s = %s.%s",
-                relationshipTableName,
+                SQLSchema.getTableOrSubselect(dictionary, relationshipClass),
                 relationshipAlias,
                 entityAlias,
-                getColumnName(entityClass, relationshipName),
+                relationshipColumnName,
                 relationshipAlias,
                 relationshipIdField);
     }

elide-datastore/elide-datastore-aggregation/src/main/java/com/yahoo/elide/datastores/aggregation/queryengines/sql/schema/SQLSchema.java

@@ -19,13 +19,16 @@
 import com.yahoo.elide.datastores.aggregation.schema.metric.Aggregation;
 import com.yahoo.elide.datastores.aggregation.schema.metric.Metric;
 
+import org.hibernate.annotations.Subselect;
+
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.ToString;
 
 import java.util.List;
 import javax.persistence.Column;
 import javax.persistence.JoinColumn;
+import javax.persistence.Table;
 
 /**
  * A subclass of Schema that supports additional metadata to construct the FROM clause of a SQL query.
@@ -116,15 +119,15 @@ protected Metric constructMetric(String metricField, Class<?> cls, EntityDiction
     /**
      * Maps a logical entity attribute into a physical SQL column name.
      * @param entityDictionary The dictionary for this elide instance.
-     * @param clazz The entity class.
+     * @param cls The entity class.
      * @param fieldName The entity attribute.
      * @return The physical SQL column name.
      */
-    public static String getColumnName(EntityDictionary entityDictionary, Class<?> clazz, String fieldName) {
-        Column[] column = entityDictionary.getAttributeOrRelationAnnotations(clazz, Column.class, fieldName);
+    public static String getColumnName(EntityDictionary entityDictionary, Class<?> cls, String fieldName) {
+        Column[] column = entityDictionary.getAttributeOrRelationAnnotations(cls, Column.class, fieldName);
 
         // this would only be valid for dimension columns
-        JoinColumn[] joinColumn = entityDictionary.getAttributeOrRelationAnnotations(clazz,
+        JoinColumn[] joinColumn = entityDictionary.getAttributeOrRelationAnnotations(cls,
                 JoinColumn.class, fieldName);
 
         if (column == null || column.length == 0) {
@@ -138,14 +141,36 @@ public static String getColumnName(EntityDictionary entityDictionary, Class<?> c
         }
     }
 
+    /**
+     * Maps an entity class to a physical table of subselect query, if neither {@link Table} nor {@link Subselect}
+     * annotation is present on this class, use the class alias as default.
+     *
+     * @param entityDictionary The dictionary for this elide instance.
+     * @param cls The entity class.
+     * @return The physical SQL table or subselect query.
+     */
+    public static String getTableOrSubselect(EntityDictionary entityDictionary, Class<?> cls) {
+        Subselect subselectAnnotation = entityDictionary.getAnnotation(cls, Subselect.class);
+
+        if (subselectAnnotation == null) {
+            Table tableAnnotation = entityDictionary.getAnnotation(cls, Table.class);
+
+            return (tableAnnotation == null)
+                    ? entityDictionary.getJsonAliasFor(cls)
+                    : tableAnnotation.name();
+        } else {
+            return "(" + subselectAnnotation.value() + ")";
+        }
+    }
+
     /**
      * Returns the physical database column name of an entity field.
-     * @param clazz The entity which owns the field.
+     * @param cls The entity which owns the field.
      * @param fieldName The field name to lookup
-     * @return
+     * @return physical database column name of an entity field
      */
-    private String getColumnName(Class<?> clazz, String fieldName) {
-        return getColumnName(entityDictionary, clazz, fieldName);
+    private String getColumnName(Class<?> cls, String fieldName) {
+        return getColumnName(entityDictionary, cls, fieldName);
     }
 
     private String getJoinColumn(Path path) {

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/AggregationDataStoreTestHarness.java

@@ -12,6 +12,7 @@
 import com.yahoo.elide.datastores.aggregation.example.Player;
 import com.yahoo.elide.datastores.aggregation.example.PlayerStats;
 import com.yahoo.elide.datastores.aggregation.example.PlayerStatsView;
+import com.yahoo.elide.datastores.aggregation.example.SubCountry;
 import com.yahoo.elide.datastores.aggregation.example.VideoGame;
 
 public class AggregationDataStoreTestHarness implements DataStoreTestHarness {
@@ -28,6 +29,7 @@ public DataStore getDataStore() {
             public void populateEntityDictionary(EntityDictionary dictionary) {
                 dictionary.bindEntity(PlayerStats.class);
                 dictionary.bindEntity(Country.class);
+                dictionary.bindEntity(SubCountry.class);
                 dictionary.bindEntity(PlayerStatsView.class);
                 dictionary.bindEntity(Player.class);
                 dictionary.bindEntity(VideoGame.class);

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/Country.java

@@ -14,13 +14,15 @@
 
 import javax.persistence.Entity;
 import javax.persistence.Id;
+import javax.persistence.Table;
 
 /**
  * A root level entity for testing AggregationDataStore.
  */
 @Data
 @Entity
 @Include(rootLevel = true)
+@Table(name = "countries")
 @Cardinality(size = CardinalitySize.SMALL)
 public class Country {
 

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/Player.java

@@ -9,16 +9,19 @@
 import com.yahoo.elide.datastores.aggregation.annotation.Cardinality;
 import com.yahoo.elide.datastores.aggregation.annotation.CardinalitySize;
 import com.yahoo.elide.datastores.aggregation.annotation.FriendlyName;
+
 import lombok.Data;
 
 import javax.persistence.Entity;
 import javax.persistence.Id;
+import javax.persistence.Table;
 
 /**
  * A root level entity for testing AggregationDataStore.
  */
 @Entity
 @Include(rootLevel = true)
+@Table(name = "players")
 @Cardinality(size = CardinalitySize.MEDIUM)
 @Data
 public class Player {

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/PlayerStats.java

@@ -24,10 +24,11 @@
 import lombok.ToString;
 
 import java.util.Date;
+import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
-import javax.persistence.OneToOne;
+import javax.persistence.ManyToOne;
 
 /**
  * A root level entity for testing AggregationDataStore.
@@ -65,11 +66,21 @@ public class PlayerStats {
      */
     private Country country;
 
+    /**
+     * A subselect dimension.
+     */
+    private SubCountry subCountry;
+
     /**
      * A dimension field joined to this table.
      */
     private String countryIsoCode;
 
+    /**
+     * A dimension field joined to this table.
+     */
+    private String subCountryIsoCode;
+
     /**
      * A table dimension.
      */
@@ -115,7 +126,7 @@ public void setOverallRating(final String overallRating) {
         this.overallRating = overallRating;
     }
 
-    @OneToOne
+    @ManyToOne
     @JoinColumn(name = "country_id")
     public Country getCountry() {
         return country;
@@ -125,7 +136,17 @@ public void setCountry(final Country country) {
         this.country = country;
     }
 
-    @OneToOne
+    @ManyToOne
+    @JoinColumn(name = "sub_country_id")
+    public SubCountry getSubCountry() {
+        return subCountry;
+    }
+
+    public void setSubCountry(final SubCountry subCountry) {
+        this.subCountry = subCountry;
+    }
+
+    @ManyToOne
     @JoinColumn(name = "player_id")
     public Player getPlayer() {
         return player;
@@ -157,4 +178,15 @@ public String getCountryIsoCode() {
     public void setCountryIsoCode(String isoCode) {
         this.countryIsoCode = isoCode;
     }
+
+
+    @JoinTo(path = "subCountry.isoCode")
+    @Column(updatable = false, insertable = false) // subselect field should be read-only
+    public String getSubCountryIsoCode() {
+        return subCountryIsoCode;
+    }
+
+    public void setSubCountryIsoCode(String isoCode) {
+        this.subCountryIsoCode = isoCode;
+    }
 }

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/PlayerStatsView.java

@@ -23,7 +23,7 @@
 @Entity
 @Include(rootLevel = true)
 @Data
-@FromSubquery(sql = "SELECT stats.highScore, stats.player_id, c.name as countryName FROM playerStats AS stats LEFT JOIN country AS c ON stats.country_id = c.id WHERE stats.overallRating = 'Great'")
+@FromSubquery(sql = "SELECT stats.highScore, stats.player_id, c.name as countryName FROM playerStats AS stats LEFT JOIN countries AS c ON stats.country_id = c.id WHERE stats.overallRating = 'Great'")
 public class PlayerStatsView {
 
     /**

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/SubCountry.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2019, Yahoo Inc.
+ * Licensed under the Apache License, Version 2.0
+ * See LICENSE file in project root for terms.
+ */
+package com.yahoo.elide.datastores.aggregation.example;
+
+import com.yahoo.elide.annotation.Include;
+import com.yahoo.elide.datastores.aggregation.annotation.Cardinality;
+import com.yahoo.elide.datastores.aggregation.annotation.CardinalitySize;
+import com.yahoo.elide.datastores.aggregation.annotation.FriendlyName;
+
+import org.hibernate.annotations.Subselect;
+
+import lombok.Data;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+/**
+ * A root level entity for testing AggregationDataStore with @Subselect annotation
+ */
+@Data
+@Entity
+@Include(rootLevel = true)
+@Subselect(value = "select * from countries")
+@Cardinality(size = CardinalitySize.SMALL)
+public class SubCountry {
+
+    private String id;
+
+    private String isoCode;
+
+    private String name;
+
+    @Id
+    public String getId() {
+        return id;
+    }
+
+    public void setId(final String id) {
+        this.id = id;
+    }
+
+    public String getIsoCode() {
+        return isoCode;
+    }
+
+    public void setIsoCode(final String isoCode) {
+        this.isoCode = isoCode;
+    }
+
+    @FriendlyName
+    public String getName() {
+        return name;
+    }
+
+    public void setName(final String name) {
+        this.name = name;
+    }
+}

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/example/VideoGame.java

@@ -14,13 +14,15 @@
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.Id;
+import javax.persistence.Table;
 
 /**
  * A root level entity for testing AggregationDataStore.
  */
 @Entity
 @Include(rootLevel = true)
-@FromTable(name = "videoGame")
+@Table(name = "videoGames")
+@FromTable(name = "videoGames")
 public class VideoGame {
 
     @Id

elide-datastore/elide-datastore-aggregation/src/test/java/com/yahoo/elide/datastores/aggregation/filter/visitor/SplitFilterExpressionVisitorTest.java

@@ -21,6 +21,7 @@
 import com.yahoo.elide.datastores.aggregation.example.Country;
 import com.yahoo.elide.datastores.aggregation.example.Player;
 import com.yahoo.elide.datastores.aggregation.example.PlayerStats;
+import com.yahoo.elide.datastores.aggregation.example.SubCountry;
 import com.yahoo.elide.datastores.aggregation.schema.Schema;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -49,6 +50,7 @@ public static void setupEntityDictionary() {
         entityDictionary = new EntityDictionary(Collections.emptyMap());
         entityDictionary.bindEntity(PlayerStats.class);
         entityDictionary.bindEntity(Country.class);
+        entityDictionary.bindEntity(SubCountry.class);
         entityDictionary.bindEntity(Player.class);
         schema = new Schema(PlayerStats.class, entityDictionary);
         splitFilterExpressionVisitor = new SplitFilterExpressionVisitor(schema);