com.netrics.likeit

Class NetricsTableCursor

java.lang.Object

com.netrics.likeit.NetricsTableCursor

All Implemented Interfaces:

java.io.Serializable

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

This class is used to scan the records in a table. A cursor allows you to scan through all records in a table, in batches of a specified size.

If the table is updated in any way after a scan with a cursor is started the results become unpredictable. The scan might skip records, or return the same record multiple times.

As long as no records are added or deleted, the ordering of records is stable: two cursors on the same table will return the records in the same order, and cursors remain valid across a checkpoint/restore.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
NetricsTableCursor(java.lang.String table_name, int batch_size) Create an initialized cursor, setting all options.
NetricsTableCursor(java.lang.String table_name, java.lang.String[] child_tables, int batch_size) Create an initialized cursor for compound records, setting all options.

Method Summary

Modifier and Type	Method and Description
boolean	atEOT() Determine if a cursor is at the end-of-table position.
int	getBatchSize() Retrieve the batch size for this cursor.
java.lang.String[]	getChildTables() Get the list of child tables for compound records.
java.lang.String	getPosition() Obtains the current cursor position.
int	getSkipCount() Gets the number of records to skip before the next batch is retrieved.
java.lang.String	getTableName() Retrieve the table name for this cursor.
void	setBatchSize(int batch_size) Set the batch size for this cursor.
void	setChildTables(java.util.List<java.lang.String> child_tables) Set the list of child tables.
void	setChildTables(java.lang.String[] child_tables) Set the list of child tables.
void	setPosition(java.lang.String pos) Reset the position of a cursor.
void	setSkipCount(int count) Sets the number of records to skip before the next batch is retrieved.

Methods inherited from class java.lang.Object

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

Constructor Detail

NetricsTableCursor

public NetricsTableCursor(java.lang.String table_name,
                          int batch_size)

Create an initialized cursor, setting all options. This creates a cursor for scanning the records of a table.

Parameters:

table_name - name of the table this cursor is on.

batch_size - number of records to be returned at a time. If <= 0 the default batch size of 1 is used.

NetricsTableCursor

public NetricsTableCursor(java.lang.String table_name,
                          java.lang.String[] child_tables,
                          int batch_size)

Create an initialized cursor for compound records, setting all options. This creates a cursor for scanning the records of a table. It sets the set of child tables to be retrieved in a compound record scan.

Parameters:

table_name - name of the table this cursor is on.

child_tables - names of all child tables to be included in a returned compound record. All tables listed must be children of table_name but validation is not performed until a scan is started. This may be null, in which case all child tables of table_name will be used in a compound record scan.

batch_size - number of records to be returned at a time. If <= 0 the default batch size of 1 is used.

Method Detail

getBatchSize

public int getBatchSize()

Retrieve the batch size for this cursor.

Returns:

the batch size for this cursor.

setBatchSize

public void setBatchSize(int batch_size)

Set the batch size for this cursor.

Parameters:

batch_size - Set the number of records to be returned at a time. If <= 0 the default batch size of 1 is used.

getTableName

public java.lang.String getTableName()

Retrieve the table name for this cursor.

Returns:

the table name for this cursor.

setChildTables

public void setChildTables(java.lang.String[] child_tables)

Set the list of child tables.

Parameters:

child_tables - names of all child tables to be included in a returned compound record. All tables listed must be children of the main table for this cursor but validation is not performed until a scan is started. This may be null, in which case all child tables of table_name are used in a compound record scan.

setChildTables

public void setChildTables(java.util.List<java.lang.String> child_tables)

Set the list of child tables.

Parameters:

child_tables - names of all child tables to be included in a returned compound record. All tables listed must be children of the main table for this cursor but validation is not performed until a scan is started. This may be null, in which case all child tables of table_name are used in a compound record scan.

getChildTables

public java.lang.String[] getChildTables()

Get the list of child tables for compound records.

Returns:

the list of child tables for compound records, null if none set.

atEOT

public boolean atEOT()

Determine if a cursor is at the end-of-table position.

Returns:

true if this cursor is at the end-of-table position.

setPosition

public void setPosition(java.lang.String pos)

Reset the position of a cursor.

This resets the position of a cursor so that it will start reading records at a given position. Note that any table update operation, including a checkpoint/restore operation, can invalidate a saved position value. The results become unpredictable.

This does not affect the skip count.

Parameters:

pos - a position value returned by a previous call to getPosition. If null, the cursor is set to the start of the table.

getPosition

public java.lang.String getPosition()

Obtains the current cursor position. This position may be used to later set the cursor position using setPosition.

Returns:

the cursor position as an encoded, opaque string value.

setSkipCount

public void setSkipCount(int count)

Sets the number of records to skip before the next batch is retrieved. Skip count is reset to zero when a batch is retrieved.

Parameters:

count - Number of records to skip. Values less than zero are treated as zero.

getSkipCount

public int getSkipCount()

Gets the number of records to skip before the next batch is retrieved. Skip count is reset to zero when a batch is retrieved.

Returns:

the number of records to skip.