simpledb

Class TupleIterator

java.lang.Object

simpledb.TupleIterator

All Implemented Interfaces:

java.io.Serializable, DbIterator

public class TupleIterator
extends java.lang.Object
implements DbIterator

Implements a DbIterator by wrapping an Iterable.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.Iterator<Tuple>	i
private static long	serialVersionUID
(package private) TupleDesc	td
(package private) java.lang.Iterable<Tuple>	tuples

Constructor Summary

Constructors

Constructor and Description
TupleIterator(TupleDesc td, java.lang.Iterable<Tuple> tuples) Constructs an iterator from the specified Iterable, and the specified descriptor.

Method Summary

Methods

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

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

i

java.util.Iterator<Tuple> i

td

TupleDesc td

tuples

java.lang.Iterable<Tuple> tuples

Constructor Detail

TupleIterator

public TupleIterator(TupleDesc td,
             java.lang.Iterable<Tuple> tuples)

Constructs an iterator from the specified Iterable, and the specified descriptor.

Parameters:

tuples - The set of tuples to iterate over

Method Detail

open

public void open()

Description copied from interface: DbIterator

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

Specified by:

open in interface DbIterator

hasNext

public boolean hasNext()

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.

next

public Tuple next()

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.

rewind

public void rewind()

Description copied from interface: DbIterator

Resets the iterator to the start.

Specified by:

rewind in interface DbIterator

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