#696 - ENH: Add fallback for @DbHstore ... fallback to JSON storage in VARCHAR

src/main/java/com/avaje/ebean/annotation/DbHstore.java

@@ -23,4 +23,8 @@ import java.lang.annotation.Target;
 @Target(ElementType.FIELD)
 public @interface DbHstore {
 
+  /**
+   * For VARCHAR storage specify the column length (defaults to 1000).
+   */
+  int length() default 0;
 }

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/AnnotationFields.java

@@ -175,8 +175,9 @@ public class AnnotationFields extends AnnotationParser {
     if (comment != null) {
       prop.setDbComment(comment.value());
     }
-    if (get(prop, DbHstore.class) != null) {
-      util.setDbHstore(prop);
+    DbHstore dbHstore = get(prop, DbHstore.class);
+    if (dbHstore != null) {
+      util.setDbHstore(prop, dbHstore);
     }
     DbJson dbJson = get(prop, DbJson.class);
     if (dbJson != null) {

src/main/java/com/avaje/ebeaninternal/server/deploy/parse/DeployUtil.java

@@ -6,6 +6,7 @@ import javax.persistence.Enumerated;
 import javax.persistence.PersistenceException;
 
 import com.avaje.ebean.annotation.DbArray;
+import com.avaje.ebean.annotation.DbHstore;
 import com.avaje.ebean.annotation.DbJson;
 import com.avaje.ebean.annotation.DbJsonB;
 import com.avaje.ebean.annotation.DbJsonType;
@@ -203,15 +204,20 @@ public class DeployUtil {
   }
 
   /**
-   * Map to Postgres HSTORE type.
+   * Map to Postgres HSTORE type (with fallback to JSON storage in VARCHAR).
    */
-  public void setDbHstore(DeployBeanProperty prop) {
-    ScalarType<?> scalarType = typeManager.getScalarType(DbType.HSTORE);
-    if (scalarType == null) {
-      throw new RuntimeException("No ScalarType found for HSTORE on [" + prop.getFullBeanName() + "] ?");
-    }
-    prop.setDbType(DbType.HSTORE);
+  public void setDbHstore(DeployBeanProperty prop, DbHstore dbHstore) {
+
+    ScalarType<?> scalarType = typeManager.getHstoreScalarType();
+    int dbType = scalarType.getJdbcType();
+    prop.setDbType(dbType);
     prop.setScalarType(scalarType);
+    if (dbType == Types.VARCHAR) {
+      // this is actually the fallback of JSON storage into VARCHAR
+      int dbLength = dbHstore.length();
+      int columnLength = (dbLength > 0) ? dbLength : DEFAULT_JSON_VARCHAR_LENGTH;
+      prop.setDbLength(columnLength);
+    }
   }
 
   /**

src/main/java/com/avaje/ebeaninternal/server/type/DefaultTypeManager.java

@@ -90,6 +90,8 @@ public final class DefaultTypeManager implements TypeManager, KnownImmutable {
 
   private final DefaultTypeFactory extraTypeFactory;
 
+  private final ScalarType<?> hstoreType = new ScalarTypePostgresHstore();
+
   private final ScalarTypeFile fileType = new ScalarTypeFile();
 
   private final ScalarType<?> charType = new ScalarTypeChar();
@@ -359,6 +361,11 @@ public final class DefaultTypeManager implements TypeManager, KnownImmutable {
     return reader;
   }
 
+  @Override
+  public ScalarType<?> getHstoreScalarType() {
+    return (postgres) ? hstoreType : ScalarTypeJsonMap.typeFor(false, Types.VARCHAR);
+  }
+
   @Override
   public ScalarType<?> getArrayScalarType(Class<?> type, DbArray dbArray, Type genericType) {
 
@@ -930,7 +937,7 @@ public final class DefaultTypeManager implements TypeManager, KnownImmutable {
     int platformClobType = databasePlatform.getClobDbType();
     int platformBlobType = databasePlatform.getBlobDbType();
 
-    nativeMap.put(DbType.HSTORE, new ScalarTypePostgresHstore());
+    nativeMap.put(DbType.HSTORE, hstoreType);
 
     ScalarType<?> utilDateType = extraTypeFactory.createUtilDate(mode);
     typeMap.put(java.util.Date.class, utilDateType);

src/main/java/com/avaje/ebeaninternal/server/type/TypeManager.java

@@ -72,4 +72,9 @@ public interface TypeManager {
    * Return the ScalarType used to handle DB ARRAY.
    */
   ScalarType<?> getArrayScalarType(Class<?> type, DbArray dbArray, Type genericType);
+
+  /**
+   * Return the ScalarType used to handle HSTORE (Map<String,String>).
+   */
+  ScalarType<?> getHstoreScalarType();
 }