Package wt.fc

Class QueryResult

java.lang.Object
wt.fc.QueryResult
All Implemented Interfaces:
Externalizable, Serializable, Enumeration
Direct Known Subclasses:
PagingQueryResult
public class QueryResult extends Object implements Enumeration, Externalizable
The QueryResult class is a container of results returned from a query. Normally, these results are accessed via the Enumeration interface which is implemented by this class. The Enumeration interface provides generic access to elements of type Object. The actual runtime type for the element is based on the type of query that is performed. For simple queries using the QuerySpec where only a single class is specified in the constructor, the element type will be Persistable. For all other queries, the safest assumption is to consider the element type to be an Object array (i.e. Object[]). In the Windchill Object-to-Relational mapping, an element in the Enumeration corresponds to a row in the result set of the query. In general, multiple classes can be specified in the query so each Object is returned as an array indexed value.

An instance of this object will internally reference each item returned from a query. When processing very large result sets, this could lead to performance issues. To handle processing large results sets, the getEnumeration() method can be called to return an Enumeration which will internally "free" references as each element is returned. This will allow the result objects to be garbage collected as soon as the object is processed and no other external references exist. When using this technique, it is important to remove (e.g. set to null) any references to the QueryResult itself, after the getEnumeration() method is called.

Supported API: true

Extendable: false

See Also:

  • Method Details

    • size

      public int size()
      Answer the number of objects in the result set.

      Supported API: true
      Returns:
      size

    • reset

      public Enumeration reset()
      Reset the enumeration to start of set.

      Supported API: true
      Returns:
      Enumeration of objects

    • getEnumeration

      public Enumeration getEnumeration()
      Returns an Enumeration of the results optimized to remove references to elements as they are returned. For very large results sets, this method can improve performance by allowing the elements to be garbage collected as soon as the object is processed and no other external references exist. When using this method, it is important to remove (e.g. set to null) any references to the QueryResult itself after this method is called.

      Supported API: true
      Returns:
      Enumeration of objects

    • hasMoreElements

      public boolean hasMoreElements()
      Indicates if more elements are available for this enumeration of the results.

      Supported API: true
      Specified by:
      hasMoreElements in interface Enumeration
      Returns:
      true if more elements are available

    • nextElement

      public Object nextElement()
      Returns the next element in this enumeration of the results.

      Supported API: true
      Specified by:
      nextElement in interface Enumeration
      Returns:
      next result object

    • getObjectVectorIfc

      public ObjectVectorIfc getObjectVectorIfc()
      Returns an ObjectVector of the results.

      Supported API: true