ExprIsNullExpression implements IBooleanExpression { public ExprIsNullExpression(IExpression expr, Boolean isNull) throws StreamingException { if (expr == null || isNull == null) { LOG.error("Arguments in '{}' operator is null.", this.getClass().getName()); StreamingException exception = new StreamingException(ErrorCode.UNKNOWN_SERVER_COMMON_ERROR); throw exception; } this.expr = expr; this.isNull = isNull; } ExprIsNullExpression(IExpression expr, Boolean isNull); @Override Object evaluate(IEvent theEvent); @Override Object evaluate(IEvent[] eventsPerStream); @Override Class< ? > getType(); IExpression getExpr();  }
@Test public void testExprIsNullExpression() { try { expr = new ExprIsNullExpression(null, true); fail(); } catch (StreamingException e) { Assert.assertTrue(true); } try { expr = new ExprIsNullExpression(toCompare, null); fail(); } catch (StreamingException e) { Assert.assertTrue(true); } }