/**
 * Redistribution and use of this software and associated documentation ("Software"), with or
 * without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
 * must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
 * without prior written permission of Intalio, Inc. For written permission, please contact
 * info@exolab.org.
 *
 * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
 * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
 * Intalio, Inc.
 *
 * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 1999-2002 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id$
 */

package org.exolab.castor.mapping;

import java.util.Properties;

/**
 * An extended version of the FieldHandler interface which is used for adding additional
 * functionality while preserving backward compatability.
 * 
 * @author <a href="kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2005-08-03 15:11:51 -0600 (Wed, 03 Aug 2005) $
 * @see FieldDescriptor
 * @see FieldHandler
 */
public abstract class AbstractFieldHandler<T> extends ExtendedFieldHandler<T>
    implements ConfigurableFieldHandler<T> {

  /**
   * The FieldDescriptor for the field that this handler is responsible for.
   */
  private FieldDescriptor _descriptor = null;

  /**
   * Configuration that can be used by subclasses when needed.
   */
  protected Properties _properties;

  /**
   * {@inheritDoc}
   */
  protected final FieldDescriptor getFieldDescriptor() {
    return _descriptor;
  }

  /**
   * {@inheritDoc}
   */
  public void setFieldDescriptor(FieldDescriptor fieldDesc) {
    _descriptor = fieldDesc;
  }

  /**
   * Returns true if the "handled" field has a value within the given object.
   * <p>
   * By default this just checks for null. Normally this method is needed for checking if a value
   * has been set via a call to the setValue method, or if the primitive value has been initialised
   * by the JVM.
   * </p>
   * <p>
   * This method should be overloaded for improved value checking.
   * </p>
   * 
   * @return true if the given object has a value for the handled field
   */
  public boolean hasValue(final Object object) {
    return (getValue(object) != null);
  }

  /**
   * Empty implementation of the {@link ConfigurableFieldHandler} interface, for convenience
   * purpose. Subclasses that want to use any configuration should override this method.
   * 
   * @param config The configuration as specified in the mapping file.
   */
  public void setConfiguration(final Properties config) throws ValidityException {}
}
