org.exolab.castor.xml.XMLFieldHandler Maven / Gradle / Ivy

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 * 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.
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 * 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
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 * 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/).
 *
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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 *
 * Copyright 1999-2003 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id$
 */

package org.exolab.castor.xml;

import org.exolab.castor.mapping.AbstractFieldHandler;

/**
 * This FieldHandler is used in the generated descriptors.
 * 
 * A field handler knows how to perform various operations on the field that require access to the
 * field value.
 * 
 * 
 * @author Assaf Arkin
 * @author Keith Visco
 * @version $Revision$ $Date: 2006-04-14 04:14:43 -0600 (Fri, 14 Apr 2006) $
 * @see org.exolab.castor.mapping.FieldDescriptor
 */
public class XMLFieldHandler extends AbstractFieldHandler {

  /**
   * Creates a new default XMLFieldHandler instance.
   */
  public XMLFieldHandler() {
    super();
  }

  /**
   * Returns true if the given object is an XMLFieldHandler that is equivalent to this one. An
   * equivalent XMLFieldHandler is an XMLFieldHandler that is an instances of the same class. This
   * method can be overwritten to provide more advanced equivalence tests.
   * 
   * @return true if the given object is an XMLFieldHandler that is equivalent to this one.
   **/
  public boolean equals(Object obj) {
    if (obj == null) {
      return false;
    }
    if (!(obj instanceof XMLFieldHandler)) {
      return false;
    }
    return getClass().isInstance(obj);
  }

  /**
   * Returns the value of the field from the object.
   * 
   * @param object The object
   * @return The value of the field
   * @throws IllegalStateException The Java object has changed and is no longer supported by this
   *         handler, or the handler is not compatiable with the Java object
   */
  public T getValue(Object object) throws IllegalStateException {
    // -- Do nothing, this method is overloaded by the
    // -- source code generator
    return null;
  }

  /**
   * Creates a new instance of the object described by this field.
   * 
   * @param parent The object for which the field is created
   * @return A new instance of the field's value
   * @throws IllegalStateException This field is a simple type and cannot be instantiated
   */
  public T newInstance(Object parent) throws IllegalStateException {
    // -- Do nothing, this method is overloaded by the
    // -- source code generator
    return null;
  }

  /**
   * Creates a new instance of the object described by this field.
   * 
   * @param parent The object for which the field is created
   * @param args the set of constructor arguments
   * @return A new instance of the field's value
   * @throws IllegalStateException This field is a simple type and cannot be instantiated
   */
  public Object newInstance(final Object parent, final Object[] args) throws IllegalStateException {
    // -- backward compatability...ignore args
    return newInstance(parent);
  }

  /**
   * Sets the value of the field on the object.
   * 
   * @param object The object.
   * @param value The new value.
   * @throws IllegalStateException The Java object has changed and is no longer supported by this
   *         handler, or the handler is not compatiable with the Java object.
   * @throws IllegalArgumentException The value passed is not of a supported type.
   */
  public void setValue(final Object object, final T value)
      throws IllegalStateException, IllegalArgumentException {
    // -- Do nothing, this method is overloaded by the
    // -- source code generator
  }

  public void resetValue(final Object object)
      throws IllegalStateException, IllegalArgumentException {
    // -- Do nothing, this method is overloaded by the
    // -- source code generator
  }
}