com.google.visualization.datasource.query
Class ColumnIsNullFilter

java.lang.Object
  com.google.visualization.datasource.query.QueryFilter
      com.google.visualization.datasource.query.ColumnIsNullFilter

public class ColumnIsNullFilter
extends QueryFilter

A filter that matches null values. Its isMatch function returns true if the value at the column is a null value (as defined by TableCell.isNull()).

Author:

Yonatan B.Y.

Constructor Summary

ColumnIsNullFilter(AbstractColumn column)
Constructs a new instance of this class with the given column ID.

Method Summary

boolean	equals(java.lang.Object obj)
protected java.util.List<AggregationColumn>	getAggregationColumns() Returns a list of all aggregation columns this filter uses.
java.util.Set<java.lang.String>	getAllColumnIds() Returns all the columnIds this filter uses.
AbstractColumn	getColumn() Returns the column that should be null.
java.util.List<ScalarFunctionColumn>	getScalarFunctionColumns() Returns a list of all scalarFunctionColumns this filter uses, in this case the scalarFunctionColumns in column (e.g, in the filter 'year(a) is null' it will return year(a).
int	hashCode()
boolean	isMatch(DataTable table, TableRow row) Checks if this row should be part of the result set.
java.lang.String	toQueryString() Returns a string that, when parsed by the query parser, should return an identical filter.

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnIsNullFilter

public ColumnIsNullFilter(AbstractColumn column)

Constructs a new instance of this class with the given column ID.

Parameters:

column - The column that should be null.

Method Detail

getColumn

public AbstractColumn getColumn()

Returns the column that should be null.

Returns:

The column that should be null.

getAllColumnIds

public java.util.Set<java.lang.String> getAllColumnIds()

Returns all the columnIds this filter uses.

Specified by:

getAllColumnIds in class QueryFilter

Returns:

All the columnIds this filter uses.

getScalarFunctionColumns

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

Returns a list of all scalarFunctionColumns this filter uses, in this case the scalarFunctionColumns in column (e.g, in the filter 'year(a) is null' it will return year(a).

Specified by:

getScalarFunctionColumns in class QueryFilter

Returns:

A list of all scalarFunctionColumns this filter uses.

getAggregationColumns

protected java.util.List<AggregationColumn> getAggregationColumns()

Returns a list of all aggregation columns this filter uses. This is kept for future use, as currently filters are not allowed to have aggregation columns. This is still used currently for validation purposes.

Specified by:

getAggregationColumns in class QueryFilter

Returns:

A list of all aggregation columns this filter uses.

isMatch

public boolean isMatch(DataTable table,
                       TableRow row)

Checks if this row should be part of the result set.

Specified by:

isMatch in class QueryFilter

Parameters:

table - The table containing this row.

row - The row to check.

Returns:

true if this row should be part of the result set, false otherwise.

toQueryString

public java.lang.String toQueryString()

Returns a string that, when parsed by the query parser, should return an identical filter. The string returned does not contain the WHERE keyword.

Specified by:

toQueryString in class QueryFilter

Returns:

A string form of this filter.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object