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java.lang.Objectuk.ac.starlink.table.join.JoinType
public abstract class JoinType
Defines how a set of matched rows from input tables
(RowLink
objects) are used to select rows for inclusion
in an output table which represents the result of the matching operation.
This is (I think) the type of the join in database terminology, though
the naming of the instances of this class do not follow that
terminology (left outer join etc).
Instances of this class are available as public static members of it. Currently, these instances should only be used with the results of pair matches (ones involving exactly two tables).
Field Summary | |
---|---|
static JoinType |
_1AND2
Selects only rows with input from both input tables. |
static JoinType |
_1NOT2
Selects only rows in the first input table which are not matched by any row in the second input table. |
static JoinType |
_1OR2
Selects rows with input from either or both input tables. |
static JoinType |
_1XOR2
Selects only rows with input from exactly one of the two input tables. |
static JoinType |
_2NOT1
Selects only rows in the second input table which are not matched by any row in the first input table. |
static JoinType |
_ALL1
Selects all output rows with input from the first input table. |
static JoinType |
_ALL2
Selects all output rows with input from the second input table. |
Method Summary | |
---|---|
abstract java.lang.String |
getDescription()
Returns a short textual description of this type. |
java.lang.String |
getName()
Returns the name of this type. |
static JoinType[] |
getPairTypes()
Returns a list of all the known types which apply to two-table matches. |
abstract boolean |
getUsedMatchFlag()
Returns a value which indicates whether the matchScore is ever non-empty in the output table. |
abstract boolean[] |
getUsedTableFlags()
Returns an array of flags indicating whether each of the tables in the input will ever have non-empty rows in the output. |
abstract LinkSet |
processLinks(LinkSet links,
int[] rowCounts)
Turns a set of links which represent matches from the matching operation into a set of links which represent the rows to output. |
java.lang.String |
toString()
Returns the name of this type. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
---|
public static final JoinType _1AND2
public static final JoinType _1OR2
public static final JoinType _ALL1
public static final JoinType _ALL2
public static final JoinType _2NOT1
public static final JoinType _1NOT2
public static final JoinType _1XOR2
Method Detail |
---|
public abstract LinkSet processLinks(LinkSet links, int[] rowCounts)
links
is a set of RowLink
objects;
if the matching operation was between two tables, each element
will represent a pair match (have two RowRef
s,
with table indices of 0 and 1 respectively).
The ordering of links
may influence the order of
the returned collection. links
may be modified
by this method, and the returned value may or may not be the
same object as the input links
itself.
links
- set of RowLinks representing actual matchesrowCounts
- numbers of rows in the tables on which the
match was performed
public abstract boolean[] getUsedTableFlags()
public abstract boolean getUsedMatchFlag()
public java.lang.String getName()
public abstract java.lang.String getDescription()
public java.lang.String toString()
toString
in class java.lang.Object
public static JoinType[] getPairTypes()
|
Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved. | ||||||||
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