simpledb

Interface DbFileIterator

All Known Implementing Classes:

AbstractDbFileIterator

public interface DbFileIterator

DbFileIterator is the iterator interface that all SimpleDB Dbfile should implement.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the iterator.
boolean	hasNext()
Tuple	next() Gets the next tuple from the operator (typically implementing by reading from a child operator or an access method).
void	open() Opens the iterator
void	rewind() Resets the iterator to the start.

Method Detail

open

void open()
   throws DbException,
          TransactionAbortedException

Opens the iterator

Throws:

DbException - when there are problems opening/accessing the database.

TransactionAbortedException

hasNext

boolean hasNext()
         throws DbException,
                TransactionAbortedException

Returns:

true if there are more tuples available, false if no more tuples or iterator isn't open.

Throws:

DbException

TransactionAbortedException

next

Tuple next()
    throws DbException,
           TransactionAbortedException,
           java.util.NoSuchElementException

Gets the next tuple from the operator (typically implementing by reading from a child operator or an access method).

Returns:

The next tuple in the iterator.

Throws:

java.util.NoSuchElementException - if there are no more tuples

DbException

TransactionAbortedException

rewind

void rewind()
     throws DbException,
            TransactionAbortedException

Resets the iterator to the start.

Throws:

DbException - When rewind is unsupported.

TransactionAbortedException

close

void close()

Closes the iterator.