Merge pull request #3474 from ebean-orm/feature/3453

#3453 - Different filterMany behavior when no matches found

Author: rbygrave

ebean-core/src/main/java/io/ebeaninternal/api/SpiQueryManyJoin.java

@@ -14,4 +14,9 @@ public interface SpiQueryManyJoin {
    * Order by clause defined via mapping on the ToMany property.
    */
   String fetchOrderBy();
+
+  /**
+   * Wrap the filter many expression with a condition allowing lEFT JOIN null matching row.
+   */
+  String idNullOr(String filterManyExpression);
 }

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanFkeyProperty.java

@@ -36,6 +36,11 @@ public String toString() {
     return "prefix:" + prefix + " name:" + name + " dbColumn:" + dbColumn + " ph:" + placeHolder;
   }
 
+  @Override
+  public String idNullOr(String filterManyExpression) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public boolean isAggregation() {
     return false;

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanProperty.java

@@ -512,6 +512,11 @@ public boolean isAssignableFrom(Class<?> type) {
     return owningType.isAssignableFrom(type);
   }
 
+  @Override
+  public String idNullOr(String filterManyExpression) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public void loadIgnore(DbReadContext ctx) {
     ctx.dataReader().incrementPos(1);

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanPropertyAssocMany.java

@@ -634,6 +634,11 @@ public String fetchOrderBy() {
     return fetchOrderBy;
   }
 
+  @Override
+  public String idNullOr(String filterManyExpression) {
+    return targetIdBinder.idNullOr(name, filterManyExpression);
+  }
+
   /**
    * Return the order by for use when lazy loading the associated collection.
    */

ebean-core/src/main/java/io/ebeaninternal/server/deploy/id/IdBinder.java

@@ -27,6 +27,11 @@ public interface IdBinder {
    */
   void initialise();
 
+  /**
+   * Wrap the filter many expression with a condition allowing lEFT JOIN null matching row.
+   */
+  String idNullOr(String name, String filterManyExpression);
+
   String idSelect();
 
   /**

ebean-core/src/main/java/io/ebeaninternal/server/deploy/id/IdBinderEmbedded.java

@@ -46,6 +46,20 @@ public void initialise() {
     this.idInValueSql = idInExpandedForm ? idInExpanded() : idInCompressed();
   }
 
+  @Override
+  public String idNullOr(String prefix, String filterManyExpression) {
+    StringBuilder sb = new StringBuilder(100);
+    sb.append("((");
+    for (int i = 0; i < props.length; i++) {
+      if (i > 0) {
+        sb.append(" and ");
+      }
+      sb.append("${").append(prefix).append('.').append(embIdProperty.name()).append('}').append(props[i].name()).append(" is null");
+    }
+    sb.append(") or (").append(filterManyExpression).append("))");
+    return sb.toString();
+  }
+
   @Override
   public String idSelect() {
     return embIdProperty.name();

ebean-core/src/main/java/io/ebeaninternal/server/deploy/id/IdBinderEmpty.java

@@ -28,6 +28,11 @@ public IdBinderEmpty() {
   public void initialise() {
   }
 
+  @Override
+  public String idNullOr(String name, String filterManyExpression) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public String idSelect() {
     return "";

ebean-core/src/main/java/io/ebeaninternal/server/deploy/id/IdBinderSimple.java

@@ -260,4 +260,9 @@ public String cacheKeyFromBean(EntityBean bean) {
     final Object value = idProperty.getValue(bean);
     return scalarType.format(value);
   }
+
+  @Override
+  public String idNullOr(String prefix, String filterManyExpression) {
+    return "(${" + prefix + "}" + idProperty.name() + " is null or (" + filterManyExpression + "))";
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/el/ElPropertyChain.java

@@ -286,4 +286,8 @@ public void pathSet(Object bean, Object value) {
     }
   }
 
+  @Override
+  public String idNullOr(String filterManyExpression) {
+    throw new UnsupportedOperationException();
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/query/CQueryPredicates.java

@@ -191,7 +191,7 @@ public void prepare(boolean buildSql) {
         if (filterManyExpr != null) {
           this.filterMany = new DefaultExpressionRequest(request, deployParser, binder, filterManyExpr);
           if (buildSql) {
-            dbFilterMany = filterMany.buildSql();
+            dbFilterMany = manyProperty.idNullOr(filterMany.buildSql());
           }
         }
       }