Package adql.db

Class DBCommonColumn

  • All Implemented Interfaces:
    DBColumn
    public class DBCommonColumn
extends java.lang.Object
implements DBColumn
    This is a special column which exists only after a NATURAL JOIN or a JOIN ... USING between two tables. It lets unify several columns of the joined tables in a single column. Thus, the writer of an ADQL query can use the column name without table prefix (since after the join there will be only one) or with a prefix table of the joined tables. The list of all covered tables is stored in this object and can be extended in case of several JOINs.
    Since:
    1.2
    Version:
    1.3 (05/2015)
    Author:
    Grégory Mantelet (ARI) - gmantele@ari.uni-heidelberg.de

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected void addCoveredTable​(DBTable table)
      Add a table that this common column must cover from now.
      DBColumn copy​(java.lang.String dbName, java.lang.String adqlName, DBTable dbTable)
      WARNING: This copy function does not make a real copy of this DBCommonColumn ! It returns a modified copy of the general column description it contains.
      java.lang.String getADQLName()
      Gets the name of this column (without any prefix and double-quotes).
      java.util.Iterator<DBTable> getCoveredTables()
      Get an iterator over the list of all tables covered by this common column.
      DBType getDatatype()
      Get the type of this column (as closed as possible from the "database" type).
      java.lang.String getDBName()
      Gets the name of this column in the "database".
      DBTable getTable()
      Gets the table which contains this DBColumn.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • generalColumnDesc

        protected DBColumn generalColumnDesc

      • lstCoveredTables

        protected java.util.ArrayList<DBTable> lstCoveredTables

    • Constructor Detail

      • DBCommonColumn

        public DBCommonColumn​(DBColumn leftCol,
                      DBColumn rightCol)
               throws UnresolvedJoinException
        Create a column which merges both of the given columns. This special DBColumn implementation is not associated with one table, and can be listed in a DBTable ONLY IF the latter is the result of a sub-query (see ADQLQuery.getResultingColumns()). A column resulting from a tables join is common only to the joined tables. That's why a list of all tables covered by this column is created or update at each merge. It can be accessed thanks to getCoveredTables(). Note: In the case one or both of the columns to join are DBCommonColumn, the list of their covered tables are also merged.
        Parameters:
        leftCol - Column of the left join table. May be a DBCommonColumn.
        rightCol - Column of the right join table. May be a DBCommonColumn.
        Throws:
        UnresolvedJoinException - If the type of the two given columns are not roughly (just testing numeric, string or geometry) compatible.

      • DBCommonColumn

        public DBCommonColumn​(DBCommonColumn toCopy,
                      java.lang.String dbName,
                      java.lang.String adqlName)
        Constructor by copy. It returns a copy of this instance of DBCommonColumn. Note: The list of covered tables is NOT deeply copied!
        Parameters:
        toCopy - The DBCommonColumn to copy.
        dbName - The new DB name of this DBCommonColumn.
        adqlName - The new ADQL name of this DBCommonColumn.

    • Method Detail

      • getADQLName

        public final java.lang.String getADQLName()
        Description copied from interface: DBColumn
        Gets the name of this column (without any prefix and double-quotes).
        Specified by:
        getADQLName in interface DBColumn
        Returns:
        Its ADQL name.

      • getDBName

        public final java.lang.String getDBName()
        Description copied from interface: DBColumn
        Gets the name of this column in the "database".
        Specified by:
        getDBName in interface DBColumn
        Returns:
        Its DB name.

      • getDatatype

        public final DBType getDatatype()
        Description copied from interface: DBColumn

        Get the type of this column (as closed as possible from the "database" type).

        Note: The returned type should be as closed as possible from a type listed by the IVOA in the TAP protocol description into the section UPLOAD.

        Specified by:
        getDatatype in interface DBColumn
        Returns:
        Its type.

      • getTable

        public final DBTable getTable()
        Description copied from interface: DBColumn
        Gets the table which contains this DBColumn.
        Specified by:
        getTable in interface DBColumn
        Returns:
        Its table or null if no table is specified.

      • getCoveredTables

        public final java.util.Iterator<DBTable> getCoveredTables()
        Get an iterator over the list of all tables covered by this common column.
        Returns:
        Iterator over all covered tables.

      • addCoveredTable

        protected void addCoveredTable​(DBTable table)
        Add a table that this common column must cover from now. Warning: no unicity check is never done !
        Parameters:
        table - Table to add in the covered tables list.