Package com.mckoi.database

Class 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 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

      • 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

      • 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