com.mckoi.database
Class FilterTable

java.lang.Object
  com.mckoi.database.Table
      com.mckoi.database.FilterTable

All Implemented Interfaces:

TableDataSource

Direct Known Subclasses:

ReferenceTable, SubsetColumnTable

public class FilterTable
extends Table

A table that is a filter for another table. By default, all Table methods are implemented to call the parent. This class should be used when we want to implement a Table filter of some kind. For example, a filter for specific columns, or even rows, etc.

NOTE: For efficiency reasons, this will store SelectableScheme objects generated by the parent like VirtualTable.

Author:

Tobias Downer

Field Summary

protected Table

parent The Table we are filtering the columns from.

Fields inherited from class com.mckoi.database.Table

DEBUG_QUERY

Constructor Summary

FilterTable(Table parent)
The Constructor.

Method Summary

int	findFieldName(Variable v) Given a fully qualified variable field name, ie.
TObject	getCellContents(int column, int row) Returns an object that represents the information in the given cell in the table.
int	getColumnCount() Returns the number of columns in the table.
Database	getDatabase() Returns the parent Database object.
DataTableDef	getDataTableDef() Returns a DataTableDef object that defines the name of the table and the layout of the columns of the table.
protected Table	getParent() Returns the parent table.
Variable	getResolvedVariable(int column) Returns a fully qualified Variable object that represents the name of the column at the given index.
int	getRowCount() Returns the number of rows stored in the table.
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.
void	printGraph(java.io.PrintStream out, int indent) Prints a graph of the table hierarchy to the stream.
RowEnumeration	rowEnumeration() Returns an Enumeration of the rows 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.Table

all, allColumnMatchesValue, 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, join, orderByColumn, orderByColumn, orderByColumn, orderByColumns, orderedRowList, outside, rangeSelect, selectAll, selectAll, selectFirst, selectLast, selectRange, selectRest, simpleJoin, simpleSelect, singleRowSelect, toMap, toString, union

Methods inherited from class java.lang.Object

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

Field Detail

parent

protected Table parent

The Table we are filtering the columns from.

Constructor Detail

FilterTable

public FilterTable(Table parent)

The Constructor.

Method Detail

getParent

protected Table getParent()

Returns the parent table.

getDatabase

public Database getDatabase()

Returns the parent Database object.

Specified by:

getDatabase in class Table

getColumnCount

public int getColumnCount()

Returns the number of columns in the table.

Specified by:

getColumnCount in class Table

getRowCount

public int getRowCount()

Returns the number of rows stored in the table.

Specified by:

getRowCount in interface TableDataSource

Specified by:

getRowCount in class Table

findFieldName

public int findFieldName(Variable v)

Given a fully qualified variable field name, ie. 'APP.CUSTOMER.CUSTOMERID' this will return the column number the field is at. Returns -1 if the field does not exist in the table.

Specified by:

findFieldName in class Table

getResolvedVariable

public Variable getResolvedVariable(int column)

Returns a fully qualified Variable object that represents the name of the column at the given index. For example, new Variable(new TableName("APP", "CUSTOMER"), "ID")

Specified by:

getResolvedVariable 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 will generally be an expensive algorithm, so calls to it should be kept to a minimum. Note that the offset between two rows is not necessarily 1.

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. The Enumeration is a fast way of retrieving consequtive rows in the table.

Specified by:

rowEnumeration in interface TableDataSource

Specified by:

rowEnumeration in class Table

getDataTableDef

public DataTableDef getDataTableDef()

Returns a DataTableDef object that defines the name of the table and the layout of the columns of the table. Note that for tables that are joined with other tables, the table name and schema for this object become mangled. For example, a table called 'PERSON' joined with a table called 'MUSIC' becomes a table called 'PERSON#MUSIC' in a null schema.

Specified by:

getDataTableDef in interface TableDataSource

Specified by:

getDataTableDef 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

printGraph

public void printGraph(java.io.PrintStream out,
                       int indent)

Prints a graph of the table hierarchy to the stream.

Overrides:

printGraph in class Table