org.apache.derby.impl.store.access.btree
Class BTreeForwardScan

java.lang.Object
  extended by org.apache.derby.impl.store.access.btree.OpenBTree
      extended by org.apache.derby.impl.store.access.btree.BTreeScan
          extended by org.apache.derby.impl.store.access.btree.BTreeForwardScan
All Implemented Interfaces:
ScanManager, GenericScanController, GroupFetchScanController, RowCountable, ScanController
Direct Known Subclasses:
B2IForwardScan

public class BTreeForwardScan
extends BTreeScan

A b-tree scan controller corresponds to an instance of an open b-tree scan.

Concurrency Notes

The concurrency rules are derived from OpenBTree.

See Also:
OpenBTree

Field Summary
 
Fields inherited from class org.apache.derby.impl.store.access.btree.BTreeScan
fetchNext_one_slot_array, init_fetchDesc, init_forUpdate, init_hold, init_lock_fetch_desc, init_qualifier, init_rawtran, init_scanColumnList, init_startKeyValue, init_startSearchOperator, init_stopKeyValue, init_stopSearchOperator, init_template, init_useUpdateLocks, lock_operation, SCAN_DONE, SCAN_HOLD_INIT, SCAN_HOLD_INPROGRESS, SCAN_INIT, SCAN_INPROGRESS, scan_position, scan_state, stat_numdeleted_rows_visited, stat_numpages_visited, stat_numrows_qualified, stat_numrows_visited
 
Fields inherited from class org.apache.derby.impl.store.access.btree.OpenBTree
btree_undo, container, err_containerid, init_lock_level, init_open_user_scans, runtime_mem
 
Fields inherited from interface org.apache.derby.iapi.store.access.ScanController
GE, GT, NA
 
Constructor Summary
BTreeForwardScan()
           
 
Method Summary
protected  int fetchRows(BTreeRowPosition pos, DataValueDescriptor[][] row_array, RowLocation[] rowloc_array, BackingStoreHashtable hash_table, long max_rowcnt, int[] key_column_numbers)
          Fetch the next N rows from the table.
protected  void positionAtStartPosition(BTreeRowPosition pos)
          Position scan at "start" position.
 
Methods inherited from class org.apache.derby.impl.store.access.btree.BTreeScan
close, closeForEndTransaction, delete, didNotQualify, doesCurrentPositionQualify, fetch, fetchLocation, fetchNext, fetchNextGroup, fetchNextGroup, fetchSet, fetchWithoutQualify, getCurrentRecordHandleForDebugging, getScanInfo, init, isCurrentPositionDeleted, isHeldAfterCommit, isKeyed, newRowLocationTemplate, next, positionAtDoneScan, positionAtDoneScanFromClose, positionAtNextPage, positionAtRowLocation, positionAtStartForForwardScan, process_qualifier, reopenScan, reopenScanByRowLocation, replace, reposition, savePositionAndReleasePage, savePositionAndReleasePage, toString
 
Methods inherited from class org.apache.derby.impl.store.access.btree.OpenBTree
checkConsistency, debugConglomerate, getColumnSortOrderInfo, getConglomerate, getContainer, getContainerHandle, getEstimatedRowCount, getHeight, getHold, getLockingPolicy, getLockLevel, getOpenMode, getRawTran, getRuntimeMem, getSpaceInfo, getXactMgr, init, isClosed, isIndexableRowConsistent, isTableLocked, reopen, setEstimatedRowCount, setLockingPolicy, test_errors
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.derby.iapi.store.access.GenericScanController
isTableLocked
 
Methods inherited from interface org.apache.derby.iapi.store.access.RowCountable
getEstimatedRowCount, setEstimatedRowCount
 

Constructor Detail

BTreeForwardScan

public BTreeForwardScan()
Method Detail

positionAtStartPosition

protected void positionAtStartPosition(BTreeRowPosition pos)
                                throws StandardException
Position scan at "start" position.

Positions the scan to the slot just before the first record to be returned from the scan. Returns the start page latched, and sets "current_slot" to the slot number.

Specified by:
positionAtStartPosition in class BTreeScan
Throws:
StandardException - Standard exception policy.

fetchRows

protected int fetchRows(BTreeRowPosition pos,
                        DataValueDescriptor[][] row_array,
                        RowLocation[] rowloc_array,
                        BackingStoreHashtable hash_table,
                        long max_rowcnt,
                        int[] key_column_numbers)
                 throws StandardException
Fetch the next N rows from the table.

Utility routine used by both fetchSet() and fetchNextGroup().

Specified by:
fetchRows in class BTreeScan
Throws:
StandardException - Standard exception policy.

Built on Thu 2011-03-10 11:54:14+0000, from revision ???

Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.