/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2006 - 2013 Pentaho Corporation and Contributors.  All rights reserved.
*/

package org.pentaho.reporting.libraries.formula.function.information;

import org.pentaho.reporting.libraries.formula.EvaluationException;
import org.pentaho.reporting.libraries.formula.FormulaContext;
import org.pentaho.reporting.libraries.formula.LibFormulaErrorValue;
import org.pentaho.reporting.libraries.formula.function.Function;
import org.pentaho.reporting.libraries.formula.function.ParameterCallback;
import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
import org.pentaho.reporting.libraries.formula.typing.coretypes.LogicalType;

/**
 * This function retruns true if the given value is of type Number.
 *
 * @author Cedric Pronzato
 */
public class IsNumberFunction implements Function {
  private static final TypeValuePair RETURN_TRUE = new TypeValuePair( LogicalType.TYPE, Boolean.TRUE );
  private static final TypeValuePair RETURN_FALSE = new TypeValuePair( LogicalType.TYPE, Boolean.FALSE );
  private static final long serialVersionUID = 3298090211745552284L;

  public IsNumberFunction() {
  }

  public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
  {
    final int parameterCount = parameters.getParameterCount();
    if (parameterCount < 1)
    {
      throw EvaluationException.getInstance(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
    }

    final Object value = parameters.getValue(0);
    if(value instanceof Number)
    {
      return RETURN_TRUE;
    }

    return RETURN_FALSE;
  }

  public String getCanonicalName() {
    return "ISNUMBER";
  }

}