org.h2.index
Class BaseHashIndex

java.lang.Object
  org.h2.engine.DbObjectBase
      org.h2.schema.SchemaObjectBase
          org.h2.index.BaseIndex
              org.h2.index.BaseHashIndex

All Implemented Interfaces:

DbObject, Index, SchemaObject

Direct Known Subclasses:

HashIndex, NonUniqueHashIndex

public abstract class BaseHashIndex
extends BaseIndex

Base of hash indexes.

Field Summary

Fields inherited from class org.h2.index.BaseIndex

columnIds, columns, indexColumns, indexType, isMultiVersion, table

Fields inherited from class org.h2.engine.DbObjectBase

comment, database, trace

Fields inherited from interface org.h2.index.Index

EMPTY_HEAD

Fields inherited from interface org.h2.engine.DbObject

AGGREGATE, COMMENT, CONSTANT, CONSTRAINT, FUNCTION_ALIAS, INDEX, RIGHT, ROLE, SCHEMA, SEQUENCE, SETTING, TABLE_OR_VIEW, TRIGGER, USER, USER_DATATYPE

Constructor Summary

BaseHashIndex(TableData table, int id, java.lang.String indexName, IndexColumn[] columns, IndexType indexType)

Method Summary

boolean	canGetFirstOrLast() Check if this index can quickly find the first or last value.
void	checkRename() Check if this object can be renamed.
void	close(Session session) Close this index.
Cursor	findFirstOrLast(Session session, boolean first) Find the first (or last) value of this index.
double	getCost(Session session, int[] masks) Calculate the cost to find rows.
protected Value	getKey(SearchRow row) Generate the search key from a row.
boolean	needRebuild() Check if this index needs to be re-built.
void	remove(Session session) Remove the index.

Methods inherited from class org.h2.index.BaseIndex

add, canFindNext, commit, compareKeys, compareRows, containsNullAndAllowMultipleNull, find, findNext, getColumnIndex, getColumnListSQL, getColumns, getCostRangeIndex, getCreateSQL, getCreateSQLForCopy, getDropSQL, getDuplicateKeyException, getIndexColumns, getIndexType, getLookupCost, getPlanSQL, getRootPageId, getTable, getType, remove, removeChildrenAndResources, truncate

Methods inherited from class org.h2.schema.SchemaObjectBase

getSchema, getSQL, initSchemaObjectBase

Methods inherited from class org.h2.engine.DbObjectBase

getChildren, getComment, getDatabase, getHeadPos, getId, getModificationId, getName, initDbObjectBase, invalidate, isTemporary, rename, setComment, setModified, setObjectName, setTemporary, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.index.Index

getRowCount, getRowCountApproximation

Methods inherited from interface org.h2.schema.SchemaObject

getSchema

Methods inherited from interface org.h2.engine.DbObject

getChildren, getComment, getDatabase, getHeadPos, getId, getModificationId, getName, getSQL, isTemporary, rename, setComment, setModified, setTemporary

Constructor Detail

BaseHashIndex

public BaseHashIndex(TableData table,
                     int id,
                     java.lang.String indexName,
                     IndexColumn[] columns,
                     IndexType indexType)

Method Detail

close

public void close(Session session)

Description copied from class: BaseIndex

Close this index.

Specified by:

close in interface Index

Specified by:

close in class BaseIndex

Parameters:

session - the session

remove

public void remove(Session session)

Description copied from class: BaseIndex

Remove the index.

Specified by:

remove in interface Index

Specified by:

remove in class BaseIndex

Parameters:

session - the session

getKey

protected Value getKey(SearchRow row)

Generate the search key from a row. Single column indexes are mapped to the value, multi-column indexes are mapped to an value array.

Parameters:

row - the row

Returns:

the value

getCost

public double getCost(Session session,
                      int[] masks)

Description copied from class: BaseIndex

Calculate the cost to find rows.

Specified by:

getCost in interface Index

Specified by:

getCost in class BaseIndex

Parameters:

session - the session

masks - the condition mask

Returns:

the cost

checkRename

public void checkRename()

Description copied from class: DbObjectBase

Check if this object can be renamed. System objects may not be renamed.

Specified by:

checkRename in interface DbObject

Specified by:

checkRename in class DbObjectBase

needRebuild

public boolean needRebuild()

Description copied from class: BaseIndex

Check if this index needs to be re-built.

Specified by:

needRebuild in interface Index

Specified by:

needRebuild in class BaseIndex

Returns:

true if it must be re-built.

canGetFirstOrLast

public boolean canGetFirstOrLast()

Description copied from class: BaseIndex

Check if this index can quickly find the first or last value.

Specified by:

canGetFirstOrLast in interface Index

Specified by:

canGetFirstOrLast in class BaseIndex

Returns:

true if it can

findFirstOrLast

public Cursor findFirstOrLast(Session session,
                              boolean first)
                       throws java.sql.SQLException

Description copied from class: BaseIndex

Find the first (or last) value of this index. The cursor returned is positioned on the correct row, or on null if no row has been found.

Specified by:

findFirstOrLast in interface Index

Specified by:

findFirstOrLast in class BaseIndex

Parameters:

session - the session

first - true for the first value, false for the last

Returns:

a cursor (never null)

Throws:

java.sql.SQLException