simpledb

Class Aggregator.TupleMapIterator

java.lang.Object

simpledb.Aggregator.TupleMapIterator

All Implemented Interfaces:

java.io.Serializable, DbIterator

Enclosing interface:

Aggregator

public static class Aggregator.TupleMapIterator
extends java.lang.Object
implements DbIterator

TupleMapIterator is class which converts HashMap < Field, Tuple > to a DbIterator.

Author:

hrily

See Also:

DbIterator, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.HashMap<Field,Tuple>	fieldTupleMap
(package private) Field[]	keyArray
(package private) int	position
(package private) TupleDesc	tupleDesc

Constructor Summary

Constructors

Constructor and Description
TupleMapIterator(java.util.HashMap<Field,Tuple> fieldTupleMap, TupleDesc tupleDesc)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the iterator.
TupleDesc	getTupleDesc() Returns the TupleDesc associated with this DbIterator.
boolean	hasNext() Returns true if the iterator has more tuples.
Tuple	next() Returns 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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

fieldTupleMap

java.util.HashMap<Field,Tuple> fieldTupleMap

tupleDesc

TupleDesc tupleDesc

keyArray

Field[] keyArray

position

int position

Constructor Detail

TupleMapIterator

public TupleMapIterator(java.util.HashMap<Field,Tuple> fieldTupleMap,
                        TupleDesc tupleDesc)

Method Detail

open

public void open()
          throws DbException,
                 TransactionAbortedException

Description copied from interface: DbIterator

Opens the iterator. This must be called before any of the other methods.

Specified by:

open in interface DbIterator

Throws:

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

TransactionAbortedException

hasNext

public boolean hasNext()
                throws DbException,
                       TransactionAbortedException

Description copied from interface: DbIterator

Returns true if the iterator has more tuples.

Specified by:

hasNext in interface DbIterator

Returns:

true f the iterator has more tuples.

Throws:

DbException

TransactionAbortedException

next

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

Description copied from interface: DbIterator

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

Specified by:

next in interface DbIterator

Returns:

the next tuple in the iteration.

Throws:

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

DbException

TransactionAbortedException

rewind

public void rewind()
            throws DbException,
                   TransactionAbortedException

Description copied from interface: DbIterator

Resets the iterator to the start.

Specified by:

rewind in interface DbIterator

Throws:

DbException - when rewind is unsupported.

TransactionAbortedException

getTupleDesc

public TupleDesc getTupleDesc()

Description copied from interface: DbIterator

Returns the TupleDesc associated with this DbIterator.

Specified by:

getTupleDesc in interface DbIterator

Returns:

the TupleDesc associated with this DbIterator.

close

public void close()

Description copied from interface: DbIterator

Closes the iterator. When the iterator is closed, calling next(), hasNext(), or rewind() should fail by throwing IllegalStateException.

Specified by:

close in interface DbIterator