simpledb

Class HeapFile.HeapFileIterator

java.lang.Object

simpledb.HeapFile.HeapFileIterator

All Implemented Interfaces:

java.io.Serializable, DbFileIterator

Enclosing class:

HeapFile

public class HeapFile.HeapFileIterator
extends java.lang.Object
implements DbFileIterator

Class for iterating over all tuples of this file

Author:

hrily

See Also:

DbFileIterator, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	numPages
(package private) Page	page
(package private) int	pageCounter
(package private) HeapPageId	pid
(package private) int	tableId
(package private) TransactionId	tid
(package private) java.util.Iterator<Tuple>	tuples

Constructor Summary

Constructors

Constructor and Description
HeapFileIterator(TransactionId tid, int tableId, int numPages) Constructor for Iterator

Method Summary

Modifier and Type	Method and Description
void	close() Close the iterator
private java.util.Iterator<Tuple>	getTuples(int pageNumber) Gets tuples from file with given page number
boolean	hasNext() Checks if iterator has next tuple
Tuple	next() Get next tuple in this file
void	open() Opens it iterator for iteration
void	rewind() Rewinds iterator to the start of file

Methods inherited from class java.lang.Object

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

Field Detail

tid

TransactionId tid

pageCounter

int pageCounter

tableId

int tableId

numPages

int numPages

page

Page page

tuples

java.util.Iterator<Tuple> tuples

pid

HeapPageId pid

Constructor Detail

HeapFileIterator

public HeapFileIterator(TransactionId tid,
                        int tableId,
                        int numPages)

Constructor for Iterator

Parameters:

tid - TransactionId of requesting transaction

tableId - id of the HeapFile

numPages - number of pages in file

Method Detail

getTuples

private java.util.Iterator<Tuple> getTuples(int pageNumber)
                                     throws DbException,
                                            TransactionAbortedException

Gets tuples from file with given page number

Parameters:

pageNumber -

Returns:

Iterator < Tuples > Iterator for tuples in the page

Throws:

DbException

TransactionAbortedException

open

public void open()
          throws DbException,
                 TransactionAbortedException

Opens it iterator for iteration

Specified by:

open in interface DbFileIterator

Throws:

DbException

TransactionAbortedException

hasNext

public boolean hasNext()
                throws DbException,
                       TransactionAbortedException

Checks if iterator has next tuple

Specified by:

hasNext in interface DbFileIterator

Returns:

boolean true if exists

Throws:

DbException

TransactionAbortedException

next

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

Get next tuple in this file

Specified by:

next in interface DbFileIterator

Returns:

Throws:

DbException

TransactionAbortedException

java.util.NoSuchElementException

rewind

public void rewind()
            throws DbException,
                   TransactionAbortedException

Rewinds iterator to the start of file

Specified by:

rewind in interface DbFileIterator

Throws:

DbException

TransactionAbortedException

close

public void close()

Close the iterator

Specified by:

close in interface DbFileIterator