com.google.visualization.datasource.query
Class ScalarFunctionColumn

java.lang.Object
  com.google.visualization.datasource.query.AbstractColumn
      com.google.visualization.datasource.query.ScalarFunctionColumn

public class ScalarFunctionColumn
extends AbstractColumn

A scalar function column (e.g. year(Date1)). The values in a scalar function column are the result of executing the function on the columns that are given as parameters, so for example year(Date1) column values will have the year of the corresponding value in Date1 column.

Author:

Liron L.

Field Summary

static java.lang.String	COLUMN_COLUMN_SEPARATOR When creating the ID of the column, this is used as a separator between the columns on which the function is performed.
static java.lang.String	COLUMN_FUNCTION_TYPE_SEPARATOR A separator between function type and the columns on which it operates.

Constructor Summary

ScalarFunctionColumn(java.util.List<AbstractColumn> columns, ScalarFunction scalarFunction)
Creates a new instance of this class with the given columns list and function type.

Method Summary

boolean	equals(java.lang.Object o)
java.util.List<AggregationColumn>	getAllAggregationColumns() Returns a list of all aggregation columns including the columns that are inside scalar function columns (e.g., the column year(date(max(d1))) will return max(d1)).
java.util.List<ScalarFunctionColumn>	getAllScalarFunctionColumns() Returns a list of all scalar function columns.
java.util.List<java.lang.String>	getAllSimpleColumnIds() Returns a list of the inner simple column IDs of the scalar function column (i.e., the columns on which the function is performed).
java.util.List<SimpleColumn>	getAllSimpleColumns() Returns a list of all simple columns.
TableCell	getCell(ColumnLookup lookup, TableRow row) Returns the cell of the column in the given row.
java.util.List<AbstractColumn>	getColumns() Returns a list of the columns on which the function is performed.
ScalarFunction	getFunction() Returns the function of the scalar function column.
java.lang.String	getId() Returns the ID of the scalar function column.
ValueType	getValueType(DataTable dataTable) Returns the value type of the column after evaluating the scalar function.
int	hashCode()
java.lang.String	toQueryString() Returns a string that when parsed by the query parser, should return an identical column.
java.lang.String	toString() This is for debug and error messages, not for ID generation.
void	validateColumn(DataTable dataTable) Checks that the column is valid.

Methods inherited from class com.google.visualization.datasource.query.AbstractColumn

getValue

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

COLUMN_FUNCTION_TYPE_SEPARATOR

public static final java.lang.String COLUMN_FUNCTION_TYPE_SEPARATOR

A separator between function type and the columns on which it operates. Used for creating the column ID.

See Also:

Constant Field Values

COLUMN_COLUMN_SEPARATOR

public static final java.lang.String COLUMN_COLUMN_SEPARATOR

When creating the ID of the column, this is used as a separator between the columns on which the function is performed.

See Also:

Constant Field Values

Constructor Detail

ScalarFunctionColumn

public ScalarFunctionColumn(java.util.List<AbstractColumn> columns,
                            ScalarFunction scalarFunction)

Creates a new instance of this class with the given columns list and function type.

Parameters:

columns - The list of columns on which the function is performed.

scalarFunction - The function type.

Method Detail

getId

public java.lang.String getId()

Returns the ID of the scalar function column. THe ID is constructed from the function's name and the IDs of the inner columns on which the function is performed.

Specified by:

getId in class AbstractColumn

Returns:

The ID of the scalar function column.

getAllSimpleColumnIds

public java.util.List<java.lang.String> getAllSimpleColumnIds()

Returns a list of the inner simple column IDs of the scalar function column (i.e., the columns on which the function is performed).

Specified by:

getAllSimpleColumnIds in class AbstractColumn

Returns:

A list of the inner simple column IDs.

getFunction

public ScalarFunction getFunction()

Returns the function of the scalar function column.

Returns:

The function of the scalar function column.

getColumns

public java.util.List<AbstractColumn> getColumns()

Returns a list of the columns on which the function is performed.

Returns:

A list of the columns on which the function is performed.

getCell

public TableCell getCell(ColumnLookup lookup,
                         TableRow row)

Returns the cell of the column in the given row. If the given column lookup contains this column, returns the cell in the given row using the lookup. Otherwise, recursively gets the inner column values and uses them to evaluate the value and create a cell based on that value. The base of the recursion is a simple column, aggregation column or another scalar function column that exists in the column lookup (i.e., its value was already calculated).

Overrides:

getCell in class AbstractColumn

Parameters:

row - The given row.

lookup - The column lookup.

Returns:

The cell of the column in the given row.

getAllSimpleColumns

public java.util.List<SimpleColumn> getAllSimpleColumns()

Returns a list of all simple columns. This includes simple columns that are inside scalar function columns (e.g, year(a1)), but does not include simple columns that are inside aggregation columns (e.g., sum(a1)).

Specified by:

getAllSimpleColumns in class AbstractColumn

Returns:

A list of all simple columns.

getAllAggregationColumns

public java.util.List<AggregationColumn> getAllAggregationColumns()

Returns a list of all aggregation columns including the columns that are inside scalar function columns (e.g., the column year(date(max(d1))) will return max(d1)).

Specified by:

getAllAggregationColumns in class AbstractColumn

Returns:

A list of all aggregation columns.

getAllScalarFunctionColumns

public java.util.List<ScalarFunctionColumn> getAllScalarFunctionColumns()

Returns a list of all scalar function columns. Returns itself and other inner scalar function columns (if there are any). e.g., the column max(year(a1), year(a2)) will return the 3 columns: max(year(a1), year(a2)), year(a1), year(a2).

Specified by:

getAllScalarFunctionColumns in class AbstractColumn

Returns:

A list of all scalar function columns.

validateColumn

public void validateColumn(DataTable dataTable)
                    throws InvalidQueryException

Checks that the column is valid. Checks the scalar function matches its arguments (inner columns) and all its inner columns are valid too. Throws a ColumnException if the scalar function has invalid arguments.

Specified by:

validateColumn in class AbstractColumn

Parameters:

dataTable - The table description.

Throws:

InvalidQueryException - Thrown when the column is invalid.

getValueType

public ValueType getValueType(DataTable dataTable)

Returns the value type of the column after evaluating the scalar function. e.g., the value type of year(date1) is NUMBER.

Specified by:

getValueType in class AbstractColumn

Parameters:

dataTable - The table description.

Returns:

the value type of the column.

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in class AbstractColumn

hashCode

public int hashCode()

Specified by:

hashCode in class AbstractColumn

toQueryString

public java.lang.String toQueryString()

Returns a string that when parsed by the query parser, should return an identical column.

Specified by:

toQueryString in class AbstractColumn

Returns:

A string form of this column.

toString

public java.lang.String toString()

This is for debug and error messages, not for ID generation.

Overrides:

toString in class java.lang.Object

Returns:

A string describing this AggregationColumn.