#1460 - ENH: Add FetchGroup ... as a mechanism to specify select() + fetch() separately from Query

src/main/java/io/ebeaninternal/server/expression/DefaultExpressionList.java

@@ -6,6 +6,7 @@ import io.ebean.DtoQuery;
 import io.ebean.Expression;
 import io.ebean.ExpressionFactory;
 import io.ebean.ExpressionList;
+import io.ebean.FetchGroup;
 import io.ebean.FetchPath;
 import io.ebean.FutureIds;
 import io.ebean.FutureList;
@@ -460,6 +461,11 @@ public class DefaultExpressionList<T> implements SpiExpressionList<T> {
     return query.select(fetchProperties);
   }
 
+  @Override
+  public Query<T> select(FetchGroup fetchGroup) {
+    return query.select(fetchGroup);
+  }
+
   @Override
   public Query<T> setDistinct(boolean distinct) {
     return query.setDistinct(distinct);

src/main/java/io/ebeaninternal/server/expression/JunctionExpression.java

@@ -5,6 +5,7 @@ import io.ebean.CountDistinctOrder;
 import io.ebean.DtoQuery;
 import io.ebean.Expression;
 import io.ebean.ExpressionList;
+import io.ebean.FetchGroup;
 import io.ebean.FetchPath;
 import io.ebean.FutureIds;
 import io.ebean.FutureList;
@@ -759,6 +760,11 @@ class JunctionExpression<T> implements SpiJunction<T>, SpiExpression, Expression
     return exprList.select(properties);
   }
 
+  @Override
+  public Query<T> select(FetchGroup fetchGroup) {
+    return exprList.select(fetchGroup);
+  }
+
   @Override
   public Query<T> setDistinct(boolean distinct) {
     return exprList.setDistinct(distinct);

src/main/java/io/ebeaninternal/server/query/DFetchGroup.java

@@ -0,0 +1,26 @@
+package io.ebeaninternal.server.query;
+
+import io.ebeaninternal.server.querydefn.OrmQueryDetail;
+import io.ebeaninternal.server.querydefn.SpiFetchGroup;
+
+/**
+ * Default FetchGroup implementation.
+ */
+class DFetchGroup implements SpiFetchGroup {
+
+  private final OrmQueryDetail detail;
+
+  DFetchGroup(OrmQueryDetail detail) {
+    this.detail = detail;
+  }
+
+  @Override
+  public OrmQueryDetail detail() {
+    return detail.copy();
+  }
+
+  @Override
+  public OrmQueryDetail underlying() {
+    return detail;
+  }
+}

src/main/java/io/ebeaninternal/server/query/DFetchGroupBuilder.java

@@ -0,0 +1,85 @@
+package io.ebeaninternal.server.query;
+
+import io.ebean.FetchConfig;
+import io.ebean.FetchGroup;
+import io.ebean.FetchGroupBuilder;
+import io.ebeaninternal.server.querydefn.OrmQueryDetail;
+import io.ebeaninternal.server.querydefn.SpiFetchGroup;
+
+/**
+ * Default implementation of the FetchGroupBuilder.
+ */
+class DFetchGroupBuilder implements FetchGroupBuilder {
+
+  private static final FetchConfig FETCH_QUERY = new FetchConfig().query();
+
+  private static final FetchConfig FETCH_LAZY = new FetchConfig().lazy();
+
+  private OrmQueryDetail detail;
+
+  DFetchGroupBuilder(OrmQueryDetail detail) {
+    this.detail = detail;
+  }
+
+  @Override
+  public FetchGroupBuilder fetch(String path) {
+    detail.fetch(path, null, null);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetch(String path, FetchGroup nestedGroup) {
+    return fetchNested(path, nestedGroup, null);
+  }
+  @Override
+  public FetchGroupBuilder fetchQuery(String path, FetchGroup nestedGroup) {
+    return fetchNested(path, nestedGroup, FETCH_QUERY);
+  }
+
+  @Override
+  public FetchGroupBuilder fetchLazy(String path, FetchGroup nestedGroup) {
+    return fetchNested(path, nestedGroup, FETCH_LAZY);
+  }
+
+  private FetchGroupBuilder fetchNested(String path, FetchGroup nestedGroup, FetchConfig fetchConfig) {
+
+    OrmQueryDetail nestedDetail = ((SpiFetchGroup) nestedGroup).underlying();
+    detail.addNested(path, nestedDetail, fetchConfig);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetchQuery(String path) {
+    detail.fetch(path, null, FETCH_QUERY);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetchLazy(String path) {
+    detail.fetch(path, null, FETCH_LAZY);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetch(String path, String properties) {
+    detail.fetch(path, properties, null);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetchQuery(String path, String properties) {
+    detail.fetch(path, properties, FETCH_QUERY);
+    return this;
+  }
+
+  @Override
+  public FetchGroupBuilder fetchLazy(String path, String properties) {
+    detail.fetch(path, properties, FETCH_LAZY);
+    return this;
+  }
+
+  @Override
+  public FetchGroup build() {
+    return new DFetchGroup(detail);
+  }
+}

src/main/java/io/ebeaninternal/server/query/DFetchGroupService.java

@@ -0,0 +1,28 @@
+package io.ebeaninternal.server.query;
+
+import io.ebean.FetchGroup;
+import io.ebean.FetchGroupBuilder;
+import io.ebean.service.SpiFetchGroupService;
+import io.ebeaninternal.server.querydefn.OrmQueryDetail;
+
+/**
+ * Default implementation of SpiFetchGroupService.
+ */
+public final class DFetchGroupService implements SpiFetchGroupService {
+
+  @Override
+  public FetchGroup of(String select) {
+    return new DFetchGroup(detail(select));
+  }
+
+  @Override
+  public FetchGroupBuilder select(String select) {
+    return new DFetchGroupBuilder(detail(select));
+  }
+
+  private OrmQueryDetail detail(String select) {
+    OrmQueryDetail detail = new OrmQueryDetail();
+    detail.select(select);
+    return detail;
+  }
+}

src/main/java/io/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -7,6 +7,7 @@ import io.ebean.Expression;
 import io.ebean.ExpressionFactory;
 import io.ebean.ExpressionList;
 import io.ebean.FetchConfig;
+import io.ebean.FetchGroup;
 import io.ebean.FetchPath;
 import io.ebean.FutureIds;
 import io.ebean.FutureList;
@@ -1329,6 +1330,12 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     return this;
   }
 
+  @Override
+  public DefaultOrmQuery<T> select(FetchGroup fetchGroup) {
+    this.detail = ((SpiFetchGroup)fetchGroup).detail();
+    return this;
+  }
+
   @Override
   public DefaultOrmQuery<T> fetch(String property) {
     return fetch(property, null, null);

src/main/java/io/ebeaninternal/server/querydefn/OrmQueryDetail.java

@@ -55,6 +55,16 @@ public class OrmQueryDetail implements Serializable {
     return copy;
   }
 
+  /**
+   * Add a nested OrmQueryDetail to this detail.
+   */
+  public void addNested(String path, OrmQueryDetail other, FetchConfig config) {
+    fetch(path, other.baseProps.getProperties(), config);
+    for (Map.Entry<String, OrmQueryProperties> entry : other.fetchPaths.entrySet()) {
+      fetch(path + "." + entry.getKey(), entry.getValue().getProperties(), entry.getValue().getFetchConfig());
+    }
+  }
+
   /**
    * Calculate the hash for the query plan.
    */

src/main/java/io/ebeaninternal/server/querydefn/OrmQueryProperties.java

@@ -148,27 +148,30 @@ public class OrmQueryProperties implements Serializable {
   /**
    * Copy constructor.
    */
-  private OrmQueryProperties(OrmQueryProperties source) {
-
+  private OrmQueryProperties(OrmQueryProperties source, FetchConfig sourceFetchConfig) {
+    this.fetchConfig = sourceFetchConfig;
     this.parentPath = source.parentPath;
     this.path = source.path;
     this.rawProperties = source.rawProperties;
     this.trimmedProperties = source.trimmedProperties;
     this.cache = source.cache;
     this.readOnly = source.readOnly;
-    this.fetchConfig = source.fetchConfig;
     this.filterMany = source.filterMany;
     this.included = (source.included == null) ? null : new LinkedHashSet<>(source.included);
-    if (includedBeanJoin != null) {
-      this.includedBeanJoin = new HashSet<>(source.includedBeanJoin);
-    }
   }
 
   /**
    * Creates a copy of the OrmQueryProperties.
    */
   public OrmQueryProperties copy() {
-    return new OrmQueryProperties(this);
+    return new OrmQueryProperties(this, this.fetchConfig);
+  }
+
+  /**
+   * Create a copy with the given fetch config.
+   */
+  public OrmQueryProperties copy(FetchConfig fetchConfig) {
+    return new OrmQueryProperties(this, fetchConfig);
   }
 
   /**

src/main/java/io/ebeaninternal/server/querydefn/SpiFetchGroup.java

@@ -0,0 +1,19 @@
+package io.ebeaninternal.server.querydefn;
+
+import io.ebean.FetchGroup;
+
+/**
+ * Service API of FetchGroup.
+ */
+public interface SpiFetchGroup extends FetchGroup {
+
+  /**
+   * Return the detail to use for query execution.
+   */
+  OrmQueryDetail detail();
+
+  /**
+   * Return the underlying detail for copy purposes.
+   */
+  OrmQueryDetail underlying();
+}