java.lang.Object
- com.mckoi.database.Table
- - com.mckoi.database.AbstractDataTable
  - - com.mckoi.database.DefaultDataTable
    - - com.mckoi.database.FunctionTable

All Implemented Interfaces:

RootTable, TableDataSource
```
public class FunctionTable
extends DefaultDataTable
```
A table that has a number of columns and as many rows as the refering table. Tables of this type are used to construct aggregate and function columns based on an expression. They are joined with the result table in the last part of the query processing.
For example, a query like 'select id, id * 2, 8 * 9 from Part' the columns 'id * 2' and '8 * 9' would be formed from this table.
SYNCHRONIZATION ISSUE: Instances of this object are NOT thread safe. The reason it's not is because if 'getCellContents' is used concurrently it's possible for the same value to be added into the cache causing an error. It is not expected that this object will be shared between threads.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

(package private) class FunctionTable.TableGroupResolver
Group resolver.
- Nested classes/interfaces inherited from class com.mckoi.database.Table
  Table.TableVariableResolver

Field Summary

Fields
Modifier and Type	Field	Description
`private QueryContext`	`context`	The context of this function table.
`private Table.TableVariableResolver`	`cr_resolver`	The TableVariableResolver for the table we are cross referencing.
`private Table`	`cross_ref_table`	The table that this function table cross references.
`private byte[]`	`exp_info`	Some information about the expression list.
`private Expression[]`	`exp_list`	The list of expressions that are evaluated to form each column.
`private DataTableDef`	`fun_table_def`	The DataTableDef object that describes the columns in this function table.
`private static TableName`	`FUNCTION_TABLE_NAME`	The table name given to all function tables.
`private IntegerVector`	`group_links`	The group row links.
`private IntegerVector`	`group_lookup`	The lookup mapping for row->group_index used for grouping.
`private FunctionTable.TableGroupResolver`	`group_resolver`	The TableGroupResolver for the table.
`private int`	`unique_id`	A unique id given to this FunctionTable when it is created.
`private static int`	`UNIQUE_KEY_SEQ`	The key used to make distinct unique ids for FunctionTables.
`private boolean`	`whole_table_as_group`	Whether the whole table is a group.
`private IntegerVector`	`whole_table_group`	If the whole table is a group, this is the grouping rows.
`private int`	`whole_table_group_size`	The total size of the whole table group size.
`private boolean`	`whole_table_is_simple_enum`	If the whole table is a simple enumeration (row index is 0 to getRowCount) then this is true.

Fields inherited from class com.mckoi.database.DefaultDataTable
row_count

Fields inherited from class com.mckoi.database.Table
DEBUG_QUERY

Constructor Summary

Constructors
Constructor	Description
`FunctionTable(Expression[] exp_list, java.lang.String[] col_names, DatabaseQueryContext context)`
`FunctionTable(Table cross_ref_table, Expression[] in_exp_list, java.lang.String[] col_names, DatabaseQueryContext context)`	Constructs the FunctionTable.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`(package private) void`	`addDataTableListener(DataTableListener listener)`	Adds a DataTableListener to the DataTable objects at the root of this table tree hierarchy.
`private TObject`	`calcValue(int column, int row, DataCellCache cache)`	Return a TObject that represents the value of the 'column', 'row' of this table.
`void`	`createGroupMatrix(Variable[] col_list)`	Creates a grouping matrix for the given tables.
`TObject`	`getCellContents(int column, int row)`	Returns an object that represents the information in the given cell in the table.
`DataTableDef`	`getDataTableDef()`	Returns the DataTableDef object that represents the columns in this function table.
`Table`	`getReferenceTable()`	Returns the Table this function is based on.
`IntegerVector`	`groupRows(int group_number)`	Returns an IntegerVector that represents the list of all rows in the group the index is at.
`int`	`groupSize(int group_number)`	The size of the group with the given number.
`boolean`	`hasRootsLocked()`	Returns true if the table has its row roots locked (via the lockRoot(int) method.
`void`	`lockRoot(int lock_key)`	Locks the root table(s) of this table so that it is impossible to overwrite the underlying rows that may appear in this table.
`(package private) IntegerVector`	`maxFromEachGroup(int col_num)`	Returns a list of rows that represent the maximum row of the given column from each distinct group in this table.
`Table`	`mergeWithReference(Variable max_column)`	Returns a Table that is this function table merged with the cross reference table.
`(package private) void`	`removeDataTableListener(DataTableListener listener)`	Removes a DataTableListener from the DataTable objects at the root of this table tree hierarchy.
`static Table`	`resultTable(DatabaseQueryContext context, int result_val)`	Returns a FunctionTable that has an int value made into a BigDecimal.
`static Table`	`resultTable(DatabaseQueryContext context, Expression expression)`	Returns a FunctionTable that has a single Expression evaluated in it.
`static Table`	`resultTable(DatabaseQueryContext context, TObject ob)`	Returns a FunctionTable that has a single TObject in it.
`static Table`	`resultTable(DatabaseQueryContext context, java.lang.Object ob)`	Returns a FunctionTable that has a single Object in it.
`RowEnumeration`	`rowEnumeration()`	Returns an Enumeration of the rows in this table.
`int`	`rowGroup(int row_index)`	Returns the group of the row at the given index.
`void`	`setWholeTableAsGroup()`	Sets the whole reference table as a single group.
`(package private) IntegerVector`	`topFromEachGroup()`	Returns a list of rows that represent one row from each distinct group in this table.
`void`	`unlockRoot(int lock_key)`	Unlocks the root tables so that the underlying rows may once again be used if they are not locked and have been removed.

Methods inherited from class com.mckoi.database.DefaultDataTable
addCellToColumnSchemes, addRowToColumnSchemes, blankSelectableSchemes, blankSelectableSchemes, clearColumnScheme, findFieldName, getColumnCount, getDatabase, getResolvedVariable, getRootColumnScheme, getRowCount, getSelectableSchemeFor, removeRowToColumnSchemes, resolveToRawTable, setToRowTableDomain

Methods inherited from class com.mckoi.database.AbstractDataTable
getTableName, toString, typeEquals

Methods inherited from class com.mckoi.database.Table
all, allColumnMatchesValue, allRowsIn, allRowsNotIn, any, columnContainsCell, columnContainsValue, columnMatchesValue, columnMerge, compareCells, Debug, distinct, distinct, dumpTo, emptySelect, exhaustiveSelect, fastFindFieldName, getColumnDefAt, getColumnScheme, getFirstCellContent, getFirstCellContent, getLastCellContent, getLastCellContent, getSingleCellContent, getSingleCellContent, getSystem, getTableAccessState, getTTypeForColumn, getTTypeForColumn, getVariableResolver, join, orderByColumn, orderByColumn, orderByColumn, orderByColumns, orderedRowList, outside, printGraph, rangeSelect, selectAll, selectAll, selectFirst, selectFromPattern, selectFromRegex, selectLast, selectRange, selectRest, selectRows, selectRows, selectRows, simpleJoin, simpleSelect, singleRowSelect, toMap, union

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - UNIQUE_KEY_SEQ
```
private static int UNIQUE_KEY_SEQ
```
    The key used to make distinct unique ids for FunctionTables.
    NOTE: This is a thread-safe static mutable variable.
  - FUNCTION_TABLE_NAME
```
private static final TableName FUNCTION_TABLE_NAME
```
    The table name given to all function tables.
  - unique_id
```
private int unique_id
```
    A unique id given to this FunctionTable when it is created. No two FunctionTable objects may have the same number. This number is between 0 and 260 million.
  - fun_table_def
```
private DataTableDef fun_table_def
```
    The DataTableDef object that describes the columns in this function table.
  - cross_ref_table
```
private Table cross_ref_table
```
    The table that this function table cross references. This is not a parent table, but more like the table we will eventually be joined with.
  - cr_resolver
```
private Table.TableVariableResolver cr_resolver
```
    The TableVariableResolver for the table we are cross referencing.
  - group_resolver
```
private FunctionTable.TableGroupResolver group_resolver
```
    The TableGroupResolver for the table.
  - exp_list
```
private Expression[] exp_list
```
    The list of expressions that are evaluated to form each column.
  - exp_info
```
private byte[] exp_info
```
    Some information about the expression list. If the value is 0 then the column is simple to solve and shouldn't be cached.
  - group_lookup
```
private IntegerVector group_lookup
```
    The lookup mapping for row->group_index used for grouping.
  - group_links
```
private IntegerVector group_links
```
    The group row links. Iterate through this to find all the rows in a group until bit 31 set.
  - whole_table_as_group
```
private boolean whole_table_as_group
```
    Whether the whole table is a group.
  - whole_table_group
```
private IntegerVector whole_table_group
```
    If the whole table is a group, this is the grouping rows. This is obtained via 'selectAll' of the reference table.
  - whole_table_group_size
```
private int whole_table_group_size
```
    The total size of the whole table group size.
  - whole_table_is_simple_enum
```
private boolean whole_table_is_simple_enum
```
    If the whole table is a simple enumeration (row index is 0 to getRowCount) then this is true.
  - context
```
private QueryContext context
```
    The context of this function table.
- Constructor Detail
  - FunctionTable
```
public FunctionTable(Table cross_ref_table,
                     Expression[] in_exp_list,
                     java.lang.String[] col_names,
                     DatabaseQueryContext context)
```
    Constructs the FunctionTable.
  - FunctionTable
```
public FunctionTable(Expression[] exp_list,
                     java.lang.String[] col_names,
                     DatabaseQueryContext context)
```
- Method Detail
  - calcValue
```
private TObject calcValue(int column,
                          int row,
                          DataCellCache cache)
```
    Return a TObject that represents the value of the 'column', 'row' of this table. If 'cache' is not null then the resultant value is added to the cache. If 'cache' is null, no caching happens.
  - setWholeTableAsGroup
```
public void setWholeTableAsGroup()
```
    Sets the whole reference table as a single group.
  - createGroupMatrix
```
public void createGroupMatrix(Variable[] col_list)
```
    Creates a grouping matrix for the given tables. The grouping matrix is arranged so that each row of the referring table that is in the group is given a number that refers to the top group entry in the group list. The group list is a linked integer list that chains through each row item in the list.
  - getReferenceTable
```
public Table getReferenceTable()
```
    Returns the Table this function is based on. We need to provide this method for aggregate functions.
  - rowGroup
```
public int rowGroup(int row_index)
```
    Returns the group of the row at the given index.
  - groupSize
```
public int groupSize(int group_number)
```
    The size of the group with the given number.
  - groupRows
```
public IntegerVector groupRows(int group_number)
```
    Returns an IntegerVector that represents the list of all rows in the group the index is at.
  - mergeWithReference
```
public Table mergeWithReference(Variable max_column)
```
    Returns a Table that is this function table merged with the cross reference table. The result table includes only one row from each group.
    The 'max_column' argument is optional (can be null). If it's set to a column in the reference table, then the row with the max value from the group is used as the group row. For example, 'Part.id' will return the row with the maximum part.id from each group.
  - topFromEachGroup
```
IntegerVector topFromEachGroup()
```
    Returns a list of rows that represent one row from each distinct group in this table. This should be used to construct a virtual table of rows from each distinct group.
  - maxFromEachGroup
```
IntegerVector maxFromEachGroup(int col_num)
```
    Returns a list of rows that represent the maximum row of the given column from each distinct group in this table. This should be used to construct a virtual table of rows from each distinct group.
  - getDataTableDef
```
public DataTableDef getDataTableDef()
```
    Returns the DataTableDef object that represents the columns in this function table.
    
    Specified by:
    
    getDataTableDef in interface TableDataSource
    
    Specified by:
    
    getDataTableDef in class Table
  - getCellContents
```
public TObject getCellContents(int column,
                               int row)
```
    Returns an object that represents the information in the given cell in the table. This can be used to obtain information about the given table cells.
    
    Specified by:
    
    getCellContents in interface TableDataSource
    
    Specified by:
    
    getCellContents in class Table
  - rowEnumeration
```
public RowEnumeration rowEnumeration()
```
    Returns an Enumeration of the rows in this table. Each call to 'nextRowIndex' returns the next valid row index in the table.
    
    Specified by:
    
    rowEnumeration in interface TableDataSource
    
    Specified by:
    
    rowEnumeration in class Table
  - addDataTableListener
```
void addDataTableListener(DataTableListener listener)
```
    Adds a DataTableListener to the DataTable objects at the root of this table tree hierarchy. If this table represents the join of a number of tables then the DataTableListener is added to all the DataTable objects at the root.
    A DataTableListener is notified of all modifications to the raw entries of the table. This listener can be used for detecting changes in VIEWs, for triggers or for caching of common queries.
    
    Specified by:
    
    addDataTableListener in class Table
  - removeDataTableListener
```
void removeDataTableListener(DataTableListener listener)
```
    Removes a DataTableListener from the DataTable objects at the root of this table tree hierarchy. If this table represents the join of a number of tables, then the DataTableListener is removed from all the DataTable objects at the root.
    
    Specified by:
    
    removeDataTableListener in class Table
  - lockRoot
```
public void lockRoot(int lock_key)
```
    Locks the root table(s) of this table so that it is impossible to overwrite the underlying rows that may appear in this table. This is used when cells in the table need to be accessed 'outside' the lock. So we may have late access to cells in the table. 'lock_key' is a given key that will also unlock the root table(s). NOTE: This is nothing to do with the 'LockingMechanism' object.
    
    Specified by:
    
    lockRoot in class Table
  - unlockRoot
```
public void unlockRoot(int lock_key)
```
    Unlocks the root tables so that the underlying rows may once again be used if they are not locked and have been removed. This should be called some time after the rows have been locked.
    
    Specified by:
    
    unlockRoot in class Table
  - hasRootsLocked
```
public boolean hasRootsLocked()
```
    Returns true if the table has its row roots locked (via the lockRoot(int) method.
    
    Specified by:
    
    hasRootsLocked in class Table
  - resultTable
```
public static Table resultTable(DatabaseQueryContext context,
                                Expression expression)
```
    Returns a FunctionTable that has a single Expression evaluated in it. The column name is 'result'.
  - resultTable
```
public static Table resultTable(DatabaseQueryContext context,
                                TObject ob)
```
    Returns a FunctionTable that has a single TObject in it. The column title is 'result'.
  - resultTable
```
public static Table resultTable(DatabaseQueryContext context,
                                java.lang.Object ob)
```
    Returns a FunctionTable that has a single Object in it. The column title is 'result'.
  - resultTable
```
public static Table resultTable(DatabaseQueryContext context,
                                int result_val)
```
    Returns a FunctionTable that has an int value made into a BigDecimal. The column title is 'result'.

Class FunctionTable

Nested Class Summary

Nested classes/interfaces inherited from class com.mckoi.database.Table

Field Summary

Fields inherited from class com.mckoi.database.DefaultDataTable

Fields inherited from class com.mckoi.database.Table

Constructor Summary

Method Summary

Methods inherited from class com.mckoi.database.DefaultDataTable

Methods inherited from class com.mckoi.database.AbstractDataTable

Methods inherited from class com.mckoi.database.Table

Methods inherited from class java.lang.Object

Field Detail

UNIQUE_KEY_SEQ

FUNCTION_TABLE_NAME

unique_id

fun_table_def

cross_ref_table

cr_resolver

group_resolver

exp_list

exp_info

group_lookup

group_links

whole_table_as_group

whole_table_group

whole_table_group_size

whole_table_is_simple_enum

context

Constructor Detail

FunctionTable

FunctionTable

Method Detail

calcValue

setWholeTableAsGroup

createGroupMatrix

getReferenceTable

rowGroup

groupSize

groupRows

mergeWithReference

topFromEachGroup

maxFromEachGroup

getDataTableDef

getCellContents

rowEnumeration

addDataTableListener

removeDataTableListener

lockRoot

unlockRoot

hasRootsLocked

resultTable

resultTable

resultTable

resultTable