com.coyotegulch.jisp

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 Summary

Modifier and Type	Method and Description
long	findKey(KeyObject key) Find the position of the object associated with a given key.
void	insertKey(KeyObject key, long pos) Insert a key into the database, associating a record position with the given key.
void	removeKey(KeyObject key) Removes the given key from the index.
void	replaceKey(KeyObject key, long pos) Replace the reference pos for the given key.
void	storeKey(KeyObject key, long pos) If the key already exists, replace the reference pos for the given key.

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