Interface ObjectIndex

  • All Known Implementing Classes:
    BTreeIndex, HashIndex

    public interface ObjectIndex
    ObjectIndex defines the concept of an index that associates key values with references to serializable objects. Concrete subclasses of ObjectIndex assume that an object's position (as given by a long value) is constant, regardless of the actual meaning of that position. In general, the position represents the * location (file pointer) of a Serializable object in an IndexedObjectDatabase. *

    * Use the IndexedObjectDatabase.attachIndex method to attach an ObjectIndex * to a database. A database updates all attached indexes when it writes or removes objects * from its file.

    See Also:
    ObjectIndex, IndexedObjectDatabase
    • Method Detail

      • insertKey

        void insertKey​(KeyObject key,
                       long pos)
                throws java.io.IOException,
                       java.lang.ClassNotFoundException
        Insert a key into the database, associating a record position with the given key. Throws a DuplicateKey exception if the key already exists.

        Parameters:
        key - A key identifying the record to be read.
        pos - File position of record associated with key
        Throws:
        java.io.IOException - when an I/O exception is thrown by an underlying java.io.* class
        java.lang.ClassNotFoundException - for a casting error, usually when a persistent object or index does match the expected type
        DuplicateKey - when inserting a duplicate key into an index that does not support duplicates
        See Also:
        DuplicateKey, KeyObject
      • replaceKey

        void replaceKey​(KeyObject key,
                        long pos)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException
        Replace the reference pos for the given key. Throws a KeyNotFound exception if the requested key does not exist in the index.
        Parameters:
        key - A key identifying the record to be read.
        pos - File position of record associated with key
        Throws:
        java.io.IOException - when an I/O exception is thrown by an underlying java.io.* class
        java.lang.ClassNotFoundException - for a casting error, usually when a persistent object or index does match the expected type
        KeyNotFound - when the specified key can not be found in the index
        See Also:
        KeyNotFound, KeyObject
      • storeKey

        void storeKey​(KeyObject key,
                      long pos)
               throws java.io.IOException,
                      java.lang.ClassNotFoundException
        If the key already exists, replace the reference pos for the given key. Otherwise, insert a key into the database, associating a record position with the given key.
        Parameters:
        key - A key identifying the record to be read.
        pos - File position of record associated with key
        Throws:
        java.io.IOException - when an I/O exception is thrown by an underlying java.io.* class
        java.lang.ClassNotFoundException - for a casting error, usually when a persistent object or index does match the expected type
        See Also:
        KeyObject
      • findKey

        long findKey​(KeyObject key)
              throws java.io.IOException,
                     java.lang.ClassNotFoundException
        Find the position of the object associated with a given key.
        Parameters:
        key - A key identifying the record to be read.
        Returns:
        The position of the record associated with key.
        Throws:
        java.io.IOException - when an I/O exception is thrown by an underlying java.io.* class
        java.lang.ClassNotFoundException - for a casting error, usually when a persistent object or index does match the expected type
        KeyNotFound - when the specified key can not be found in the index
        See Also:
        KeyNotFound, KeyObject
      • removeKey

        void removeKey​(KeyObject key)
                throws java.io.IOException,
                       java.lang.ClassNotFoundException
        Removes the given key from the index.
        Parameters:
        key - A key identifying the record to be read.
        Throws:
        java.io.IOException - when an I/O exception is thrown by an underlying java.io.* class
        java.lang.ClassNotFoundException - for a casting error, usually when a persistent object or index does match the expected type
        KeyNotFound - when the specified key can not be found in the index
        See Also:
        KeyNotFound, KeyObject