/*
 * 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) 2001 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors..  All rights reserved.
 */

package org.pentaho.reporting.engine.classic.core.filter.types;

import org.pentaho.reporting.engine.classic.core.AttributeNames;
import org.pentaho.reporting.engine.classic.core.ReportElement;
import org.pentaho.reporting.engine.classic.core.function.ExpressionRuntime;

public class ContentFieldType extends ContentType {
  public static final ContentFieldType INSTANCE = new ContentFieldType();

  public ContentFieldType() {
    super( "content-field" );
  }

  protected ContentFieldType( final String id ) {
    super( id );
  }

  public Object getDesignValue( final ExpressionRuntime runtime, final ReportElement element ) {
    final Object staticValue = ElementTypeUtils.queryStaticValue( element );
    if ( staticValue != null ) {
      return staticValue;
    }
    return ElementTypeUtils.queryFieldName( element );
  }

  /**
   * Returns the current value for the data source.
   *
   * @param runtime
   *          the expression runtime that is used to evaluate formulas and expressions when computing the value of this
   *          filter.
   * @param element
   *          the element for which the data is computed.
   * @return the value.
   */
  public Object getValue( final ExpressionRuntime runtime, final ReportElement element ) {
    if ( runtime == null ) {
      throw new NullPointerException( "Runtime must never be null." );
    }
    if ( element == null ) {
      throw new NullPointerException( "Element must never be null." );
    }

    final Object value = ElementTypeUtils.queryFieldOrValue( runtime, element );
    if ( value != null ) {
      final Object filteredValue = filter( runtime, element, value );
      if ( filteredValue != null ) {
        return filteredValue;
      }
    }
    final Object nullValue = element.getAttribute( AttributeNames.Core.NAMESPACE, AttributeNames.Core.NULL_VALUE );
    return filter( runtime, element, nullValue );
  }
}