Class JoinedTable

java.lang.Object
com.mckoi.database.Table
com.mckoi.database.JoinedTable
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
  • Field Details

    • reference_list

      protected Table[] reference_list
      The list of tables that make up the join.
    • column_scheme

      protected SelectableScheme[] column_scheme
      The schemes to describe the entity relation in the given column.
    • column_table

      protected int[] column_table
      Maps the column number in this table to the reference_list array to route to.
    • column_filter

      protected int[] column_filter
      Gives a column filter to the given column to route correctly to the ancestor.
  • Constructor Details

    • JoinedTable

      protected JoinedTable()
      Protected constructor.
  • Method Details

    • init

      protected void init(Table[] tables)
      Helper function for initializing the variables in the joined table.
    • getDatabase

      public Database getDatabase()
      We simply pick the first table to resolve the Database object.
      Specified by:
      getDatabase in class Table
    • 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 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 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 class Table
    • getReferenceTables

      protected final Table[] getReferenceTables()
      Returns the list of Table objects that represent this VirtualTable.
    • 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 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.
      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
    • 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(PrintStream out, int indent)
      Prints a graph of the table hierarchy to the stream.
      Overrides:
      printGraph in class Table
    • 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.
    • 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.