/libformula-1.1.3/source/org/pentaho/reporting/libraries/formula/function/text/TFunction.java

 1/*
 2 * This program is free software; you can redistribute it and/or modify it under the
 3 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
 4 * Foundation.
 5 *
 6 * You should have received a copy of the GNU Lesser General Public License along with this
 7 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 8 * or from the Free Software Foundation, Inc.,
 9 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
12 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13 * See the GNU Lesser General Public License for more details.
14 *
15 * Copyright (c) 2006 - 2009 Pentaho Corporation and Contributors.  All rights reserved.
16 */
17
18package org.pentaho.reporting.libraries.formula.function.text;
19
20import org.pentaho.reporting.libraries.formula.EvaluationException;
21import org.pentaho.reporting.libraries.formula.FormulaContext;
22import org.pentaho.reporting.libraries.formula.LibFormulaErrorValue;
23import org.pentaho.reporting.libraries.formula.function.Function;
24import org.pentaho.reporting.libraries.formula.function.ParameterCallback;
25import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
26import org.pentaho.reporting.libraries.formula.typing.Type;
27import org.pentaho.reporting.libraries.formula.typing.coretypes.TextType;
28
29/**
30 * This function returns the given text value or a zero lenght string for non text type.
31 *
32 * @author Cedric Pronzato
33 *
34 */
35public class TFunction implements Function
36{
37  private static final TypeValuePair EMPTY_STRING = new TypeValuePair(TextType.TYPE, "");
38  private static final long serialVersionUID = 5792821944649583654L;
39
40  public TFunction()
41  {
42  }
43
44  public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
45  {
46    final int parameterCount = parameters.getParameterCount();
47    if (parameterCount < 1)
48    {
49      throw EvaluationException.getInstance(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
50    }
51    final Type type1 = parameters.getType(0);
52    final Object value1 = parameters.getValue(0);
53
54    if(type1 instanceof TextType || value1 instanceof String)
55    {
56      return new TypeValuePair(TextType.TYPE, value1);
57    }
58    else
59    {
60      return EMPTY_STRING;
61    }
62  }
63
64  public String getCanonicalName()
65  {
66    return "T";
67  }
68
69}