com.sleepycat.je

Class JoinConfig

java.lang.Object

com.sleepycat.je.JoinConfig

All Implemented Interfaces:

java.lang.Cloneable

public class JoinConfig
extends java.lang.Object
implements java.lang.Cloneable

The configuration properties of a JoinCursor. The join cursor configuration is specified when calling Database.join.

To create a configuration object with default attributes:

     JoinConfig config = new JoinConfig();
 

To set custom attributes:

     JoinConfig config = new JoinConfig();
     config.setNoSort(true);
 

See Also:

Database.join, JoinCursor

Field Summary

Fields

Modifier and Type	Field and Description
static JoinConfig	DEFAULT Default configuration used if null is passed to Database.join.

Constructor Summary

Constructors

Constructor and Description
JoinConfig() Creates an instance with the system's default settings.

Method Summary

Methods

Modifier and Type	Method and Description
(package private) JoinConfig	cloneConfig() Used by SecondaryDatabase to create a copy of the application supplied configuration.
boolean	getNoSort() Returns whether automatic sorting of the input cursors is disabled.
void	setNoSort(boolean noSort) Specifies whether automatic sorting of the input cursors is disabled.
java.lang.String	toString() Returns the values for each configuration attribute.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final JoinConfig DEFAULT

Default configuration used if null is passed to Database.join.

Constructor Detail

JoinConfig

public JoinConfig()

Creates an instance with the system's default settings.

Method Detail

setNoSort

public void setNoSort(boolean noSort)

Specifies whether automatic sorting of the input cursors is disabled.

Joined values are retrieved by doing a sequential iteration over the first cursor in the cursor array, and a nested iteration over each following cursor in the order they are specified in the array. This requires database traversals to search for the current datum in all the cursors after the first. For this reason, the best join performance normally results from sorting the cursors from the one that refers to the least number of data items to the one that refers to the most. Unless this method is called with true, Database.join does this sort on behalf of its caller.

If the data are structured so that cursors with many data items also share many common elements, higher performance will result from listing those cursors before cursors with fewer data items; that is, a sort order other than the default. Calling this method permits applications to perform join optimization prior to calling Database.join.

Parameters:

noSort - whether automatic sorting of the input cursors is disabled.

See Also:

Database.join

getNoSort

public boolean getNoSort()

Returns whether automatic sorting of the input cursors is disabled.

Returns:

whether automatic sorting of the input cursors is disabled.

See Also:

setNoSort(boolean)

cloneConfig

JoinConfig cloneConfig()

Used by SecondaryDatabase to create a copy of the application supplied configuration. Done this way to provide non-public cloning.

toString

public java.lang.String toString()

Returns the values for each configuration attribute.

Overrides:

toString in class java.lang.Object

Returns:

the values for each configuration attribute.