Class AbstractFunction

  • All Implemented Interfaces:
    Column, SQLFunction

    public abstract class AbstractFunction
    extends Object
    implements SQLFunction
    A default framework that implements the core SQLFunction interface requirements that can be used to build specific functions on.
    Version:
    $Id: AbstractFunction.java 1879896 2020-07-15 15:03:46Z gk $
    Author:
    Greg Monroe
    • Constructor Detail

      • AbstractFunction

        protected AbstractFunction()
        Functions should only be created via the FunctionFactory class.
    • Method Detail

      • getSqlExpression

        public abstract String getSqlExpression()
        This should return the SQL string that can be used when constructing the query. E.g. "AVG( table.column )" or CONCAT(table.column, " foobar");
        Specified by:
        getSqlExpression in interface Column
        Returns:
        The SQL String.
      • getArguments

        public Object[] getArguments()
        Return all the parameters as an object array. This allow for processing of the parameters in their original format rather than just in String format. E.g. a parameter might be specified as a Date object, or a Column object.
        Specified by:
        getArguments in interface SQLFunction
        Returns:
        Should return a valid Object array and not null. E.g. implementors should return new Object[0] if there are no parameters.
      • setArguments

        public void setArguments​(Object... args)
        Sets the function arguments.
        Specified by:
        setArguments in interface SQLFunction
        Parameters:
        args - the function arguments, not null.
      • getColumn

        public Column getColumn()
        Returns the column to which this function is applied.
        Specified by:
        getColumn in interface SQLFunction
        Returns:
        the column, not null.
        Throws:
        IllegalStateException - if the column cannot be determined.
      • getArgument

        public Object getArgument​(int index)
        Return the object representation of the function parameter at the specified index. Will be null if parameter does not exist.
        Specified by:
        getArgument in interface SQLFunction
        Parameters:
        index - The 0 based index of the parameter to get.
        Returns:
        The parameter object. Null if one does not exist.
      • addArgument

        protected void addArgument​(Object arg)
        Add an argument to the function argument list
        Parameters:
        arg - The argument object.
      • setArgumentList

        protected void setArgumentList​(List<Object> args)
        Set the full function argument list.
        Parameters:
        args - The new argument list
      • getArgumentList

        protected List<Object> getArgumentList()
        Get the full list of function arguments
        Returns:
        The argument list
      • getColumnName

        public String getColumnName()
        Returns the column name. This implementation always return null because we do not reference a real column.
        Specified by:
        getColumnName in interface Column
        Returns:
        the column name, always null.
      • getTableName

        public String getTableName()
        Returns the name of the associated table (not prefixed by the schema name) from the function argument(s). In case that no unique table name can be determined, null is returned.
        Specified by:
        getTableName in interface Column
        Returns:
        the name of the table, may be null but not blank.
      • getSchemaName

        public String getSchemaName()
        Returns the name of any fixed schema prefix for the column's table (if any) from the function argument(s). In case that no unique schema can be determined, null is returned.
        Specified by:
        getSchemaName in interface Column
        Returns:
        the schema name, or null if the schema is not known.
      • getFullTableName

        public String getFullTableName()
        Returns the table name prefixed with the schema name if it exists from the function argument(s). I.e. if a schema name exists, the result will be schemaName.tableName, and otherwise it will just be tableName. In case that no unique full table can be determined, null is returned.
        Specified by:
        getFullTableName in interface Column
        Returns:
        the fully qualified table name may be null but not blank.