Class QueryResults


  • public final class QueryResults
    extends java.lang.Object
    The result of a query in the context of a transaction. A query is executed against the cache engine in the context of a transaction. The result of a query is this object that can be used to obtain the next object in the query.
    Version:
    $Revision: 7951 $ $Date: 2006-04-22 11:05:30 -0600 (Sat, 22 Apr 2006) $
    Author:
    Assaf Arkin
    • Method Detail

      • getTransaction

        public TransactionContext getTransaction()
        Returns the transaction context in which this query was opened. The transaction may be closed.
        Returns:
        The query's transaction context
      • getQuery

        public PersistenceQuery getQuery()
        Returns the associated query.
        Returns:
        The query
      • getResultType

        public java.lang.Class getResultType()
        Returns the type of object returned by this query.
        Returns:
        The type of object returned by this query
      • nextIdentity

        public java.lang.Object nextIdentity()
                                      throws PersistenceException
        Returns the identity of the next object to be returned. Calling this method multiple time will skip objects. When the result set has been exhuasted, this method will return null.
        Returns:
        The identity of the next object
        Throws:
        PersistenceException - An error reported by the persistence engine
        TransactionNotInProgressException - The transaction has been closed
      • fetch

        public java.lang.Object fetch()
                               throws PersistenceException
        Loads the specified object with the identity. The identity must have been retrieved with a call to nextIdentity().

        If the object is locked by another transaction this method will block until the lock is released, or a timeout occured. If a timeout occurs or the object has been deleted by the other transaction, this method will report an. The query may proceed to the next identity.

        If the object has been deleted in this transaction, this method will report an. However, the caller may iterate to and obtain the next object.

        This method is equivalent to TransactionContext.fetch(org.exolab.castor.persist.ClassMolder, org.exolab.castor.persist.spi.Identity, org.exolab.castor.mapping.AccessMode) with a know cache engine, identity and lock and acts on the query results rather than issuing a new query to load the object.

        Returns:
        The loaded object
        Throws:
        PersistenceException - An error reported by the persistence engine. The object was not found in persistent storage. The transaction has been closed. Could not acquire a lock on the object.
      • close

        public void close()
        Close the query and release all resources held by the query.