Package com.mckoi.database

Class CompositeTable

  • All Implemented Interfaces:
    RootTable, TableDataSource
    public class CompositeTable
extends Table
implements RootTable
    A composite of two or more datasets used to implement UNION, INTERSECTION, and DIFFERENCE.

    • Field Detail

      • UNION

        public static int UNION
        The composite function for finding the union of the tables.

      • INTERSECT

        public static int INTERSECT
        The composite function for finding the interestion of the tables.

      • EXCEPT

        public static int EXCEPT
        The composite function for finding the difference of the tables.

      • master_table

        private Table master_table
        The 'master table' used to resolve information about this table such as fields and field types.

      • composite_tables

        private Table[] composite_tables
        The tables being made a composite of.

      • table_indexes

        private IntegerVector[] table_indexes
        The list of indexes of rows to include in each table.

      • column_scheme

        private SelectableScheme[] column_scheme
        The schemes to describe the entity relation in the given column.

      • roots_locked

        private int roots_locked
        The number of root locks on this table.

    • Constructor Detail

      • CompositeTable

        public CompositeTable​(Table master_table,
                      Table[] composite_list)
        Constructs the composite table given the 'master_table' (the field structure this composite dataset is based on), and a list of tables to be the composite of this table. The 'master_table' must be one of the elements of the 'composite_list' array.

        NOTE: This does not set up table indexes for a composite function.

      • CompositeTable

        public CompositeTable​(Table[] composite_list)
        Consturcts the composite table assuming the first item in the list is the master table.

    • Method Detail

      • removeDuplicates

        private void removeDuplicates​(boolean pre_sorted)
        Removes duplicate rows from the table. If 'pre_sorted' is true then each composite index is already in sorted order.

      • setupIndexesForCompositeFunction

        public void setupIndexesForCompositeFunction​(int function,
                                             boolean all)
        Sets up the indexes in this composite table by performing for composite function on the tables. If the 'all' parameter is true then duplicate rows are removed.

      • getDatabase

        public Database getDatabase()
        Description copied from class: Table
        Returns the Database object that this table is derived from.
        Specified by:
        getDatabase in class Table

      • getColumnCount

        public int getColumnCount()
        Description copied from class: Table
        Returns the number of columns in the table.
        Specified by:
        getColumnCount in class Table

      • findFieldName

        public int findFieldName​(Variable v)
        Description copied from class: Table
        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

      • getDataTableDef

        public DataTableDef getDataTableDef()
        Description copied from class: Table
        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

      • getResolvedVariable

        public Variable getResolvedVariable​(int column)
        Description copied from class: Table
        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

      • getSelectableSchemeFor

        SelectableScheme getSelectableSchemeFor​(int column,
                                        int original_column,
                                        Table table)
        Description copied from class: Table
        Returns a SelectableScheme for the given column in the given VirtualTable row domain. The 'column' variable may be modified as it traverses through the tables, however the 'original_column' retains the link to the column in 'table'.
        Specified by:
        getSelectableSchemeFor in class Table

      • setToRowTableDomain

        void setToRowTableDomain​(int column,
                         IntegerVector row_set,
                         TableDataSource ancestor)
        Description copied from class: Table
        Given a set, this trickles down through the Table hierarchy resolving the given row_set to a form that the given ancestor understands. Say you give the set { 0, 1, 2, 3, 4, 5, 6 }, this function may check down three levels and return a new 7 element set with the rows fully resolved to the given ancestors domain.
        Specified by:
        setToRowTableDomain in class Table

      • getCellContents

        public TObject getCellContents​(int column,
                               int row)
        Description copied from class: Table
        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. Use 'rowEnumeration' to get the contents of a set.
        Specified by:
        getCellContents in interface TableDataSource
        Specified by:
        getCellContents in class Table

      • rowEnumeration

        public RowEnumeration rowEnumeration()
        Description copied from class: Table
        Returns an Enumeration of the rows in this table. Each call to 'RowEnumeration.nextRowIndex()' returns the next valid row in the table. Note that the order that rows are retreived depend on a number of factors. For a DataTable the rows are accessed in the order they are in the data file. For a VirtualTable, the rows are accessed in the order of the last select operation.

        If you want the rows to be returned by a specific column order then use the 'selectxxx' methods.

        Specified by:
        rowEnumeration in interface TableDataSource
        Specified by:
        rowEnumeration in class Table

      • addDataTableListener

        void addDataTableListener​(DataTableListener listener)
        Description copied from class: Table
        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)
        Description copied from class: Table
        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)
        Description copied from class: Table
        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)
        Description copied from class: Table
        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()
        Description copied from class: Table
        Returns true if the table has its row roots locked (via the lockRoot(int) method.
        Specified by:
        hasRootsLocked in class Table

      • typeEquals

        public boolean typeEquals​(RootTable table)
        Description copied from interface: RootTable
        This is function is used to check that two root tables are identical. This is used if we need to chect that the form of the table is the same. Such as in a union operation, when we can only union two tables with the identical columns.
        Specified by:
        typeEquals in interface RootTable