simpledb

Class JoinPredicate

java.lang.Object

simpledb.JoinPredicate

All Implemented Interfaces:

java.io.Serializable

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

JoinPredicate compares fields of two tuples using a predicate. JoinPredicate is most likely used by the Join operator.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private int	field1
private int	field2
private Predicate.Op	op
private static long	serialVersionUID

Constructor Summary

Constructors

Constructor and Description
JoinPredicate(int field1, Predicate.Op op, int field2) Constructor -- create a new predicate over two fields of two tuples.

Method Summary

Modifier and Type	Method and Description
java.util.List<Tuple>	applyAll(DbIterator iterator1, DbIterator iterator2)
private java.util.List<Tuple>	applyOne(Tuple tuple, java.util.List<Tuple> tuples)
boolean	filter(Tuple t1, Tuple t2) Apply the predicate to the two specified tuples.
int	getField1()
int	getField2()
Predicate.Op	getOperator()

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

field1

private int field1

field2

private int field2

op

private Predicate.Op op

Constructor Detail

JoinPredicate

public JoinPredicate(int field1,
                     Predicate.Op op,
                     int field2)

Constructor -- create a new predicate over two fields of two tuples.

Parameters:

field1 - The field index into the first tuple in the predicate

field2 - The field index into the second tuple in the predicate

op - The operation to apply (as defined in Predicate.Op); either Predicate.Op.GREATER_THAN, Predicate.Op.LESS_THAN, Predicate.Op.EQUAL, Predicate.Op.GREATER_THAN_OR_EQ, or Predicate.Op.LESS_THAN_OR_EQ

See Also:

Predicate

Method Detail

filter

public boolean filter(Tuple t1,
                      Tuple t2)

Apply the predicate to the two specified tuples. The comparison can be made through Field's compare method.

Parameters:

t1 - First tuple

t2 - Second tuple

Returns:

true if the tuples satisfy the predicate.

getField1

public int getField1()

Returns:

First field

getField2

public int getField2()

Returns:

First field

getOperator

public Predicate.Op getOperator()

Returns:

The predicate operator

applyAll

public java.util.List<Tuple> applyAll(DbIterator iterator1,
                                      DbIterator iterator2)
                               throws DbException,
                                      TransactionAbortedException

Throws:

DbException

TransactionAbortedException

applyOne

private java.util.List<Tuple> applyOne(Tuple tuple,
                                       java.util.List<Tuple> tuples)