Package org.odmg

Interface DCollection

  • All Superinterfaces:
    java.util.Collection, java.lang.Iterable
    All Known Subinterfaces:
    DArray, DBag, DList, DSet
    All Known Implementing Classes:
    RasBag, RasCollection, RasList, RasSet
    public interface DCollection
extends java.util.Collection
    The base interface for all ODMG collections. The ODMG collections are based on JavaSoft's collection interfaces. All of the operations defined by the JavaSoft Collection interface are supported by an ODMG implementation of DCollection; the exception UnsupportedOperationException is not thrown when a call is made to any of the Collection methods.

    DCollection contains methods used to perform queries on the collection. The OQL query predicate is given as a string with the syntax of the where clause of OQL. The predefined OQL variable this is used inside the predicate to denote the current element of the collection.

    Author:
    David Jordan (as Java Editor of the Object Data Management Group)

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      boolean existsElement​(java.lang.String predicate)
      Determines whether there is an element of the collection that evaluates to true for the predicate,
      not yet available in RasDaMan.
      DCollection query​(java.lang.String predicate)
      Evaluate the boolean query predicate for each element of the collection and return a new collection that contains each element that evaluated to true,
      not yet available in RasDaMan.
      java.util.Iterator select​(java.lang.String predicate)
      Access all of the elements of the collection that evaluate to true for the provided query predicate,
      not yet available in RasDaMan.
      java.lang.Object selectElement​(java.lang.String predicate)
      Selects the single element of the collection for which the provided OQL query predicate is true,
      not yet available in RasDaMan.

      • Methods inherited from interface java.util.Collection

        add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray, toArray

      • Methods inherited from interface java.lang.Iterable

        forEach

    • Method Detail

      • selectElement

        java.lang.Object selectElement​(java.lang.String predicate)
                        throws QueryInvalidException
        Selects the single element of the collection for which the provided OQL query predicate is true,
        not yet available in RasDaMan.
        Parameters:
        predicate - An OQL boolean query predicate.
        Returns:
        The element that evaluates to true for the predicate. If no element evaluates to true, null is returned.
        Throws:
        QueryInvalidException - The query predicate is invalid.

      • select

        java.util.Iterator select​(java.lang.String predicate)
                   throws QueryInvalidException
        Access all of the elements of the collection that evaluate to true for the provided query predicate,
        not yet available in RasDaMan.
        Parameters:
        predicate - An OQL boolean query predicate.
        Returns:
        An iterator used to iterate over the elements that evaluated true for the predicate.
        Throws:
        QueryInvalidException - The query predicate is invalid.

      • query

        DCollection query​(java.lang.String predicate)
           throws QueryInvalidException
        Evaluate the boolean query predicate for each element of the collection and return a new collection that contains each element that evaluated to true,
        not yet available in RasDaMan.
        Parameters:
        predicate - An OQL boolean query predicate.
        Returns:
        A new collection containing the elements that evaluated true for the predicate.
        Throws:
        QueryInvalidException - The query predicate is invalid.

      • existsElement

        boolean existsElement​(java.lang.String predicate)
               throws QueryInvalidException
        Determines whether there is an element of the collection that evaluates to true for the predicate,
        not yet available in RasDaMan.
        Parameters:
        predicate - An OQL boolean query predicate.
        Returns:
        True if there is an element of the collection that evaluates to true for the predicate, otherwise false.
        Throws:
        QueryInvalidException - The query predicate is invalid.