org.pentaho.reporting.engine.classic.core.filter
Class EmptyDataSource

java.lang.Object
  extended by org.pentaho.reporting.engine.classic.core.filter.EmptyDataSource
All Implemented Interfaces:
Serializable, Cloneable, DataSource

public final class EmptyDataSource
extends Object
implements DataSource

A data source that always returns null.

Author:
Thomas Morgner
See Also:
Serialized Form

Constructor Summary
EmptyDataSource()
          Default-Constructor.
 
Method Summary
 Object clone()
          Clones the data source.
 Object getValue(ExpressionRuntime runtime, Element element)
          Returns the value for the data source (always null in this case).
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

EmptyDataSource

public EmptyDataSource()
Default-Constructor.

Method Detail

getValue

public Object getValue(ExpressionRuntime runtime,
                       Element element)
Returns the value for the data source (always null in this case).

Specified by:
getValue in interface DataSource
Parameters:
runtime - the expression runtime that is used to evaluate formulas and expressions when computing the value of this filter.
element -
Returns:
always null.

clone

public Object clone()
Clones the data source.

Specified by:
clone in interface DataSource
Overrides:
clone in class Object
Returns:
a clone.