Package com.mckoi.database
Class JoinedTable
- java.lang.Object
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- com.mckoi.database.Table
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- com.mckoi.database.JoinedTable
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- All Implemented Interfaces:
TableDataSource
- Direct Known Subclasses:
NaturallyJoinedTable
,VirtualTable
public abstract class JoinedTable extends Table
A Table that represents the result of one or more other tables joined together. VirtualTable and NaturallyJoinedTable are derived from this class.- Author:
- Tobias Downer
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Field Summary
Fields Modifier and Type Field Description protected int[]
column_filter
Gives a column filter to the given column to route correctly to the ancestor.protected SelectableScheme[]
column_scheme
The schemes to describe the entity relation in the given column.protected int[]
column_table
Maps the column number in this table to the reference_list array to route to.protected Table[]
reference_list
The list of tables that make up the join.-
Fields inherited from class com.mckoi.database.Table
DEBUG_QUERY
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Constructor Summary
Constructors Modifier Constructor Description protected
JoinedTable()
Protected constructor.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description 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()
We simply pick the first table to resolve the Database object.DataTableDef
getDataTableDef()
Returns the DataTableDef object that describes the columns in this table.protected Table[]
getReferenceTables()
Returns the list of Table objects that represent this VirtualTable.Variable
getResolvedVariable(int column)
Returns a fully qualified Variable object that represents the name of the column at the given index.boolean
hasRootsLocked()
Returns true if the table has its row roots locked (via the lockRoot(int) method.protected void
init(Table[] tables)
Helper function for initializing the variables in the joined table.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.protected abstract void
resolveAllRowsForTableAt(IntegerVector row_set, int table_num)
Given an IntegerVector that represents a list of pointers to rows in this table, this resolves the rows to row indexes in the given parent table.protected abstract int
resolveRowForTableAt(int row_number, int table_num)
Given a row and a table index (to a parent reference table), this will return the row index in the given parent table for the given row.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, getRowCount, 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
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Field Detail
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reference_list
protected Table[] reference_list
The list of tables that make up the join.
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column_scheme
protected SelectableScheme[] column_scheme
The schemes to describe the entity relation in the given column.
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column_table
protected int[] column_table
Maps the column number in this table to the reference_list array to route to.
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column_filter
protected int[] column_filter
Gives a column filter to the given column to route correctly to the ancestor.
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Method Detail
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init
protected void init(Table[] tables)
Helper function for initializing the variables in the joined table.
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getDatabase
public Database getDatabase()
We simply pick the first table to resolve the Database object.- Specified by:
getDatabase
in classTable
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getColumnCount
public int getColumnCount()
Returns the number of columns in the table. This simply returns the column counts in the parent table(s).- Specified by:
getColumnCount
in classTable
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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 classTable
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getResolvedVariable
public final 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 classTable
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getReferenceTables
protected final Table[] getReferenceTables()
Returns the list of Table objects that represent this VirtualTable.
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getDataTableDef
public DataTableDef getDataTableDef()
Returns the DataTableDef object that describes the columns in this table. For a VirtualTable, this object contains the union of all the columns in the children in the order set. The name of a virtual table is the concat of all the parent table names. The schema is set to null.- Specified by:
getDataTableDef
in interfaceTableDataSource
- Specified by:
getDataTableDef
in classTable
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getCellContents
public TObject getCellContents(int column, int row)
Returns an object that represents the information in the given cell in the table.- Specified by:
getCellContents
in interfaceTableDataSource
- Specified by:
getCellContents
in classTable
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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 interfaceTableDataSource
- Specified by:
rowEnumeration
in classTable
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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.
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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 classTable
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hasRootsLocked
public boolean hasRootsLocked()
Returns true if the table has its row roots locked (via the lockRoot(int) method.- Specified by:
hasRootsLocked
in classTable
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printGraph
public void printGraph(java.io.PrintStream out, int indent)
Prints a graph of the table hierarchy to the stream.- Overrides:
printGraph
in classTable
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resolveRowForTableAt
protected abstract int resolveRowForTableAt(int row_number, int table_num)
Given a row and a table index (to a parent reference table), this will return the row index in the given parent table for the given row.
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resolveAllRowsForTableAt
protected abstract void resolveAllRowsForTableAt(IntegerVector row_set, int table_num)
Given an IntegerVector that represents a list of pointers to rows in this table, this resolves the rows to row indexes in the given parent table. This method changes the 'row_set' IntegerVector object.
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