simpledb

Class Tuple

java.lang.Object

simpledb.Tuple

All Implemented Interfaces:

java.io.Serializable

public class Tuple
extends java.lang.Object
implements java.io.Serializable

Tuple maintains information about the contents of a tuple. Tuples have a specified schema specified by a TupleDesc object and contain Field objects with the data for each field.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.List<Field>	fieldValues
private RecordId	recordId
private static long	serialVersionUID
private TupleDesc	tupleDesc

Constructor Summary

Constructors

Constructor and Description
Tuple(TupleDesc td) Create a new tuple with the specified schema (type).

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object o)
java.util.Iterator<Field>	fields()
Field	getField(int i)
RecordId	getRecordId()
TupleDesc	getTupleDesc()
int	hashCode()
static Tuple	merge(Tuple t1, Tuple t2) Merges two tuples
void	removeField(int i) Removes a field from the tuple Also chages the tuple desc accordingly
void	setField(int i, Field f) Change the value of the ith field of this tuple.
void	setRecordId(RecordId rid) Set the RecordId information for this tuple.
static java.util.List<Tuple>	sortedList(DbIterator iterator, int field)
java.lang.String	toString() Returns the contents of this Tuple as a string.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

tupleDesc

private TupleDesc tupleDesc

recordId

private RecordId recordId

fieldValues

java.util.List<Field> fieldValues

Constructor Detail

Tuple

public Tuple(TupleDesc td)

Create a new tuple with the specified schema (type).

Parameters:

td - the schema of this tuple. It must be a valid TupleDesc instance with at least one field.

Method Detail

getTupleDesc

public TupleDesc getTupleDesc()

Returns:

The TupleDesc representing the schema of this tuple.

getRecordId

public RecordId getRecordId()

Returns:

The RecordId representing the location of this tuple on disk. May be null.

setRecordId

public void setRecordId(RecordId rid)

Set the RecordId information for this tuple.

Parameters:

rid - the new RecordId for this tuple.

setField

public void setField(int i,
                     Field f)

Change the value of the ith field of this tuple.

Parameters:

i - index of the field to change. It must be a valid index.

f - new value for the field.

getField

public Field getField(int i)

Parameters:

i - field index to return. Must be a valid index.

Returns:

the value of the ith field, or null if it has not been set.

toString

public java.lang.String toString()

Returns the contents of this Tuple as a string. Note that to pass the system tests, the format needs to be as follows: column1\tcolumn2\tcolumn3\t...\tcolumnN\n where \t is any whitespace, except newline, and \n is a newline

Overrides:

toString in class java.lang.Object

fields

public java.util.Iterator<Field> fields()

Returns:

An iterator which iterates over all the fields of this tuple

merge

public static Tuple merge(Tuple t1,
                          Tuple t2)

Merges two tuples

Parameters:

t1 - Tuple 1

t2 - Tuple 2

Returns:

tuple The merged Tuple

removeField

public void removeField(int i)

Removes a field from the tuple Also chages the tuple desc accordingly

Parameters:

i - The index of field to remove

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

sortedList

public static java.util.List<Tuple> sortedList(DbIterator iterator,
                                               int field)
                                        throws DbException,
                                               TransactionAbortedException

Throws:

DbException

TransactionAbortedException