Package edu.caltech.nanodb.plannodes

Class TableFunctionScanNode

java.lang.Object

edu.caltech.nanodb.plannodes.PlanNode

edu.caltech.nanodb.plannodes.TableFunctionScanNode

All Implemented Interfaces:

java.lang.Cloneable

public class TableFunctionScanNode
extends PlanNode

A select plan-node that produces the output of a specific table-returning function, checking the optional predicate against each tuple. Note that the planner is at the mercy of whatever statistics and other relevant information are reported by the table-returning function.

Field Summary

Fields

Modifier and Type	Field	Description
private TableFunction	tableFunc	The table-returning function whose tuples will be output by this plan-node.

Fields inherited from class edu.caltech.nanodb.plannodes.PlanNode

cost, environment, leftChild, rightChild, schema, stats

Constructor Summary

Constructors

Constructor	Description
TableFunctionScanNode(TableFunction tableFunc)

Method Summary

Modifier and Type	Method	Description
void	cleanUp()	Perform any necessary clean up tasks.
boolean	equals(java.lang.Object obj)	Checks if the argument is a plan node tree with the same structure, but not necesarily the same references.
Tuple	getNextTuple()	Gets the next tuple that fulfills the conditions for this plan node.
int	hashCode()	Computes the hash-code of a plan-node, including any sub-plans of this plan.
void	prepare()	This method is responsible for computing critical details about the plan node, such as the schema of the results that are produced, the estimated cost of evaluating the plan node (and its children), and statistics describing the results produced by the plan node.
java.util.List<OrderByExpression>	resultsOrderedBy()	If the results are ordered in some way, this method returns a collection of expressions specifying what columns or expressions the results are ordered by.
java.lang.String	toString()	Reports this node and its vital parameters as a string.

Methods inherited from class edu.caltech.nanodb.plannodes.PlanNode

addParentEnvironmentToPlanTree, clone, duplicate, getCost, getEnvironment, getSchema, getStats, initialize, markCurrentPosition, printNodeTree, printNodeTree, printNodeTree, printNodeTreeToString, printNodeTreeToString, requiresLeftMarking, requiresRightMarking, resetToLastMark, setEnvironment, supportsMarking

Methods inherited from class java.lang.Object

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

Field Detail

tableFunc

private TableFunction tableFunc

The table-returning function whose tuples will be output by this plan-node.

Constructor Detail

TableFunctionScanNode

public TableFunctionScanNode(TableFunction tableFunc)

Method Detail

getNextTuple

public Tuple getNextTuple()

Description copied from class: PlanNode

Gets the next tuple that fulfills the conditions for this plan node. If the node has a child, it should call getNextTuple() on the child. If the node is a leaf, the tuple comes from some external source such as a table file, the network, etc.

Specified by:

getNextTuple in class PlanNode

Returns:

the next tuple to be generated by this plan, or null if the plan has finished generating plan nodes.

resultsOrderedBy

public java.util.List<OrderByExpression> resultsOrderedBy()

Description copied from class: PlanNode

If the results are ordered in some way, this method returns a collection of expressions specifying what columns or expressions the results are ordered by. If the results are not ordered then this method may return either an empty list or a null value.

When this method returns a list of ordering expressions, the order of the expressions themselves also matters. The entire set of results will be ordered by the first expression; rows with the same value for the first expression will be ordered by the second expression; etc.

Specified by:

resultsOrderedBy in class PlanNode

Returns:

If the plan node produces ordered results, this will be a list of objects specifying the ordering. If the node doesn't produce ordered results then the return-value will either be an empty list or it will be null.

prepare

public void prepare()

Description copied from class: PlanNode

This method is responsible for computing critical details about the plan node, such as the schema of the results that are produced, the estimated cost of evaluating the plan node (and its children), and statistics describing the results produced by the plan node.

Specified by:

prepare in class PlanNode

cleanUp

public void cleanUp()

Description copied from class: PlanNode

Perform any necessary clean up tasks. This should probably be called when we are done with this plan node.

Specified by:

cleanUp in class PlanNode

toString

public java.lang.String toString()

Description copied from class: PlanNode

Reports this node and its vital parameters as a string.

Specified by:

toString in class PlanNode

Returns:

the node in string format.

equals

public boolean equals(java.lang.Object obj)

Description copied from class: PlanNode

Checks if the argument is a plan node tree with the same structure, but not necesarily the same references.

Specified by:

equals in class PlanNode

Parameters:

obj - the object to which we are comparing

hashCode

public int hashCode()

Description copied from class: PlanNode

Computes the hash-code of a plan-node, including any sub-plans of this plan. This method is used to see if two plan nodes (or subtrees) might be equal.

Specified by:

hashCode in class PlanNode

Returns:

the hash code for the plan node and any subnodes it may contain.