relop
Class Tuple

java.lang.Object
  relop.Tuple

public class Tuple
extends java.lang.Object

Each tuple in a relation is a collection of bytes that must fit within a single page. The Tuple class provides a logical view of fields, allowing get and set operations while automatically handling offsets and type conversions.

Field Summary

protected byte[]	data Page buffer containing this tuple.
protected Schema	schema Schema information for the fields.

Constructor Summary

Tuple(Schema schema)
Creates a new empty tuple, given its schema.

Tuple(Schema schema, byte[] data)
Creates a new tuple, given existing values to wrap.

Tuple(Schema schema, java.lang.Object... values)
Creates a new tuple, given its schema and values.

Method Summary

java.lang.Object[]	getAllFields() Returns generic values for all fields.
byte[]	getData() Gets the underlying data buffer.
java.lang.Object	getField(int fldno) Gets a field's value generically.
java.lang.Object	getField(java.lang.String fldName) Gets a field's value generically, by column name.
float	getFloatFld(int fldno) Gets a float field.
int	getIntFld(int fldno) Gets an integer field.
java.lang.String	getStringFld(int fldno) Gets a string field.
RID	insertIntoFile(HeapFile file) Inserts the tuple into the given heap file.
static Tuple	join(Tuple t1, Tuple t2, Schema schema) Builds and returns a new tuple resulting from joining two tuples.
protected void	padOutput(int fieldLen, int outputLen) Pads the current output to make columns line up.
void	print() Prints the tuple in a human-readable format.
void	setAllFields(java.lang.Object... values) Sets all fields, given generic values.
void	setField(int fldno, java.lang.Object val) Sets a field's value generically.
void	setField(java.lang.String fldName, java.lang.Object val) Sets a field's value generically, by column name.
void	setFloatFld(int fldno, float val) Sets a float field.
void	setIntFld(int fldno, int val) Sets an integer field.
void	setStringFld(int fldno, java.lang.String val) Sets a string field (automatically truncates, if necessary).

Methods inherited from class java.lang.Object

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

Field Detail

data

protected byte[] data

Page buffer containing this tuple.

schema

protected Schema schema

Schema information for the fields.

Constructor Detail

Tuple

public Tuple(Schema schema)

Creates a new empty tuple, given its schema.

Parameters:

schema - logical information for the fields

Tuple

public Tuple(Schema schema,
             java.lang.Object... values)

Creates a new tuple, given its schema and values.

Parameters:

schema - logical information for the fields

values - individual data values of the fields

Tuple

public Tuple(Schema schema,
             byte[] data)

Creates a new tuple, given existing values to wrap.

Parameters:

schema - logical information for the fields

data - record buffer containing the tuple

Method Detail

join

public static Tuple join(Tuple t1,
                         Tuple t2,
                         Schema schema)

Builds and returns a new tuple resulting from joining two tuples.

Parameters:

t1 - the left tuple

t2 - the right tuple

schema - of the result

getData

public byte[] getData()

Gets the underlying data buffer.

insertIntoFile

public RID insertIntoFile(HeapFile file)

Inserts the tuple into the given heap file.

getField

public java.lang.Object getField(int fldno)

Gets a field's value generically.

getField

public java.lang.Object getField(java.lang.String fldName)

Gets a field's value generically, by column name.

setField

public void setField(int fldno,
                     java.lang.Object val)

Sets a field's value generically.

setField

public void setField(java.lang.String fldName,
                     java.lang.Object val)

Sets a field's value generically, by column name.

getAllFields

public java.lang.Object[] getAllFields()

Returns generic values for all fields.

setAllFields

public void setAllFields(java.lang.Object... values)

Sets all fields, given generic values.

getIntFld

public int getIntFld(int fldno)

Gets an integer field.

setIntFld

public void setIntFld(int fldno,
                      int val)

Sets an integer field.

getFloatFld

public float getFloatFld(int fldno)

Gets a float field.

setFloatFld

public void setFloatFld(int fldno,
                        float val)

Sets a float field.

getStringFld

public java.lang.String getStringFld(int fldno)

Gets a string field.

setStringFld

public void setStringFld(int fldno,
                         java.lang.String val)

Sets a string field (automatically truncates, if necessary).

print

public void print()

Prints the tuple in a human-readable format.

padOutput

protected void padOutput(int fieldLen,
                         int outputLen)

Pads the current output to make columns line up.

Parameters:

fieldLen - minimum length of the current field

outputLen - length of the current output so far