Package io.permazen

Class UntypedPermazenObject

java.lang.Object
io.permazen.UntypedPermazenObject
All Implemented Interfaces:
PermazenObject
public abstract class UntypedPermazenObject extends Object implements PermazenObject
Represents a PermazenObject for which no Java model type is defined in the instance's associated schema.

Instances of this class are used to represent objects with a type that is defined in some other database schema but not in the current one. This situation can occur when a new schema drops a previously defined Java model type when there are objects still existing in the database. If encountered, such objects are represented by instances of this class.

These objects are still fully accessible, but they must be accessed via introspection using the PermazenTransaction field access methods, with the migrateSchema parameter set to false (to prevent a TypeNotInSchemaException).

For example, suppose a schema update removes the Account class and replaces fields referencing Account objects with a simple String account ID field. Then the corresponding schema migration might look like this: 

      @OnSchemaChange
      private void applySchemaChanges(Map<String, Object> oldValues) {
          if (oldValues.containsKey("account")) {                         // was replaced with "accountId"
              final PermazenObject acct = (PermazenObject)oldValues.get("account");     // acct has type UntypedPermazenObject
              final PermazenTransaction ptx = this.getTransaction();
              final String acctId = (String)ptx.readSimpleField(acct.getObjId(), "accountId", false);
              this.setAccountId(acctId);
          }
          // ...etc
      }

  • Constructor Details

    • UntypedPermazenObject

      public UntypedPermazenObject()