org.eclipse.linuxtools.tmf.core/src/org/eclipse/linuxtools/tmf/core/statevalue/NullStateValue.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012, 2013 Ericsson
   3  * Copyright (c) 2010, 2011 École Polytechnique de Montréal
   4  * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com>
   5  *
   6  * All rights reserved. This program and the accompanying materials are
   7  * made available under the terms of the Eclipse Public License v1.0 which
   8  * accompanies this distribution, and is available at
   9  * http://www.eclipse.org/legal/epl-v10.html
  10  *
  11  *******************************************************************************/
  12
  13 package org.eclipse.linuxtools.tmf.core.statevalue;
  14
  15 /**
  16  * A state value that contains no particular value. It is sometimes needed over
  17  * a "null" reference, since we avoid NPE's this way.
  18  *
  19  * It can also be read either as a String ("nullValue") or an Integer (-1).
  20  *
  21  * @version 1.0
  22  * @author Alexandre Montplaisir
  23  */
  24 final class NullStateValue extends TmfStateValue {
  25
  26     @Override
  27     public Type getType() {
  28         return Type.NULL;
  29     }
  30
  31     @Override
  32     public boolean isNull() {
  33         return true;
  34     }
  35
  36     @Override
  37     public Object getValue() {
  38         return null;
  39     }
  40
  41     @Override
  42     public String toString() {
  43         return "nullValue"; //$NON-NLS-1$
  44     }
  45 }