/*
 * 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 2004 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id: ValueOfFieldHandler.java 6671 2007-01-02 05:57:46Z ekuns $
 */
package org.exolab.castor.xml.handlers;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.exolab.castor.mapping.FieldDescriptor;
import org.exolab.castor.mapping.FieldHandler;
import org.exolab.castor.mapping.GeneralizedFieldHandler;
import org.exolab.castor.mapping.MappingException;

/**
 * An implementation of GeneralizedFieldHandler for classes that have a built-in
 * valueOf(String) factory method, such as type-safe enumeration classes,
 * java.sql.Timestamp, etc.
 *
 * @author <a href="kvisco@intalio.com">Keith Visco</a>
 * @version $Revision: 6671 $ $Date: 2006-04-14 04:14:43 -0600 (Fri, 14 Apr 2006) $
 * @see FieldDescriptor
 * @see FieldHandler
 */
public class ValueOfFieldHandler extends GeneralizedFieldHandler {

    /** The Class[] holding the argument types of the factory method. */
    private static final Class[] ARGS = new Class[] {String.class};
    /** The Factory Method name. */
    private static final String METHOD_NAME = "valueOf";

    /** The class type for this FieldHandler. */
    private final Class _type;
    /** The <code>valueOf</code> method reference. */
    private final Method _valueOf;

    /**
     * Creates a new ValueOfFieldHandler.
     *
     * @param type the class type to create the FieldHandler for
     * @throws MappingException if the valueOf method cannot be found
     */
    public ValueOfFieldHandler(final Class type) throws MappingException {
        super();
        if (type == null) {
            throw new IllegalArgumentException("The argument 'type' must not be null.");
        }

        _type = type;

        Method method = null;
        try {
            method = type.getMethod(METHOD_NAME, ARGS);
        } catch (java.lang.NoSuchMethodException nsme) {
            throw new MappingException(nsme);
        }
        if (!Modifier.isStatic(method.getModifiers())) {
            String err = "No static method '" + METHOD_NAME + "' found in class: " + type.getName();
            throw new MappingException(err);
        }

        _valueOf = method;
    } //-- ValueOfFieldHandler

    /**
     * This method is used to convert the value when the getValue method is
     * called. The getValue method will obtain the actual field value from given
     * 'parent' object. This convert method is then invoked with the field's
     * value. The value returned from this method will be the actual value
     * returned by getValue method.
     *
     * @param value the object value to convert after performing a get operation
     * @return the converted value.
     */
    public Object convertUponGet(final Object value) {
        //-- no conversion necessary for marshaling
        return value;
    } //-- convertUponGet

    /**
     * This method is used to convert the value when the setValue method is
     * called. The setValue method will call this method to obtain the converted
     * value. The converted value will then be used as the value to set for the
     * field.
     *
     * @param value the object value to convert before performing a set
     *        operation
     * @return the converted value.
     */
    public Object convertUponSet(final Object value) {
        Object[] args = new Object[1];

        if (value != null) {
            args[0] = value.toString();
        }

        Object result = null;

        try {
            result = _valueOf.invoke(null, args);
        } catch (java.lang.IllegalAccessException iae) {
            throw new IllegalStateException(iae.getMessage());
        } catch (java.lang.reflect.InvocationTargetException ite) {
            throw new IllegalStateException(ite.getMessage());
        }

        return result;
    } //-- convertUponSet;

    /**
     * Returns the class type for the field that this GeneralizedFieldHandler
     * converts to and from. This should be the type that is used in the object
     * model.
     *
     * @return the class type of of the field
     */
    public Class getFieldType() {
        return _type;
    } //-- getFieldType

    /**
     * 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 Object newInstance(final Object parent) throws IllegalStateException {
        return null;
    }

} // -- ValueOfFieldHandler
