org.opengts.dbtools
Class DBRecordIterator<DBR extends DBRecord>

java.lang.Object
  org.opengts.dbtools.DBRecordIterator<DBR>

public class DBRecordIterator<DBR extends DBRecord>
extends java.lang.Object

DBRecordIterator is used to iterate through a DBRecord selection.
This DBRecordIterator currently uses the SQL DB provider OFFSET/LIMIT keywords to iterate through a selection, and thus is only supported by DB providers that support these keywords. This method has the disadvantage that record insertions/deletions occurring while this DBRecordIterator is in use may cause this iterator to possibly miss some records, or produce duplicate records.

Field Summary

static long

DEFAULT_LIMIT

Constructor Summary

DBRecordIterator(DBR[] records)
Constructor

DBRecordIterator(DBSelect<DBR> dbSel)
Constructor

DBRecordIterator(java.lang.Iterable<DBR> iterable)
Constructor

DBRecordIterator(java.util.Iterator<DBR> iterator)
Constructor

Method Summary

protected java.util.Iterator<DBR>	fetch() Preloads the next block of records to return.
protected DBSelect<DBR>	getDBSelect()
long	getLimit() Gets the block size limit
boolean	hasNext() Returns true if another DBRecord is available from the iterator
DBR	next() Returns the next object from the iterator
void	setLimit(long limit) Sets the limit block size

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_LIMIT

public static final long DEFAULT_LIMIT

See Also:

Constant Field Values

Constructor Detail

DBRecordIterator

public DBRecordIterator(DBR[] records)

Constructor

Parameters:

records - An array of DBRecord

DBRecordIterator

public DBRecordIterator(java.lang.Iterable<DBR> iterable)

Constructor

Parameters:

iterable - An Iterable

DBRecordIterator

public DBRecordIterator(java.util.Iterator<DBR> iterator)

Constructor

Parameters:

iterator - An iterator

DBRecordIterator

public DBRecordIterator(DBSelect<DBR> dbSel)
                 throws DBException

Constructor

Parameters:

dbSel - The DBSelect instance

Throws:

DBException - if the DBProvider does not support offset/limit.

Method Detail

getLimit

public long getLimit()

Gets the block size limit

Returns:

The block size limit

setLimit

public void setLimit(long limit)

Sets the limit block size

Parameters:

limit - The block size limit

hasNext

public boolean hasNext()
                throws DBException

Returns true if another DBRecord is available from the iterator

Returns:

True if another DBRecord is available from the iterator

Throws:

DBException - if a DB access error occurs.

next

public DBR next()
                          throws DBException,
                                 DBNotFoundException

Returns the next object from the iterator

Returns:

The next object

Throws:

DBException - if a DB access error occurs.

DBNotFoundException - if there ore no more DBRecords to return

getDBSelect

protected DBSelect<DBR> getDBSelect()

fetch

protected java.util.Iterator<DBR> fetch()
                                                  throws DBException,
                                                         DBNotFoundException

Preloads the next block of records to return.

Returns:

The DBRecord iterator

Throws:

DBException

DBNotFoundException