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*
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* THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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*
* Copyright 2002 (C) Intalio, Inc. All Rights Reserved.
*
* $Id$
*/
package org.exolab.castor.xml.handlers;
import org.exolab.castor.mapping.FieldHandler;
import org.exolab.castor.mapping.ValidityException;
import org.exolab.castor.xml.util.ContainerElement;
/**
* The FieldHandler for ContainerElement.
*
* @author <a href="kvisco@intalio.com">Keith Visco</a>
* @version $Revision$ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $
* @see FieldDescriptor org.exolab.castor.mapping.FieldDescriptor
* @see FieldHandler org.exolab.castor.mapping.FieldHandler
*/
public final class ContainerFieldHandler implements FieldHandler {
/** Automatically choose the mode to use. */
public static final int MODE_AUTO = 0;
/** When the field is not a ContainerElement, this mode is used. */
public static final int MODE_PARENT_LINK = 1;
/** The mode for a ContainerElement. getValue and setValue operate on the parent. */
public static final int MODE_CHILD_LINK = 2;
/** The actual FieldHandler to delegate to. */
private final FieldHandler _handler;
/** Mode to use for this ContainerFieldHandler. */
private final int _mode = MODE_AUTO;
/**
* Creates a new ContainerFieldHandler with the given FieldHandler.
* @param handler The field handler to delegate to.
*/
public ContainerFieldHandler(final FieldHandler handler) {
super();
_handler = handler;
} //-- ContainerFieldHandler
//-----------------------------/
//- Methods from FieldHandler -/
//-----------------------------/
/**
* Returns the value of the field from the object. If mode is
* MODE_CHILD_LINK or mode is MODE_AUTO and the object is a
* ContainerElement, then the value of the parent is returned. Otherwise, a
* new ContainerElement is returned. The value of this new ContainerElement
* is the value of the provided object and the parent of the new
* ContainerElement is the provided object.
*
* @param object The object to get the value of
* @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
* compatible with the Java object
*/
public Object getValue(final Object object) throws IllegalStateException {
int mode = _mode;
if (mode == MODE_AUTO) {
if (object instanceof ContainerElement) {
mode = MODE_CHILD_LINK;
} else {
mode = MODE_PARENT_LINK;
}
}
if (mode == MODE_CHILD_LINK) {
return _handler.getValue(((ContainerElement) object).getParent());
}
// MODE_PARENT_LINK
ContainerElement container = new ContainerElement(_handler.getValue(object));
container.setParent(object);
return container;
} //-- getValue
/**
* Creates a new instance of the object described by this field. Of the
* object provided is a ContainerElement, then a new isntance of the parent
* object is returned. Otherwise a new ContainerElement is created and
* returned, with the parent set to the provided object.
*
* @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 {
//-- MODE_CHILD_LINK and MODE_AUTO
if (parent instanceof ContainerElement) {
return _handler.newInstance(((ContainerElement) parent).getParent());
}
// MODE_PARENT_LINK
ContainerElement container = new ContainerElement();
container.setParent(parent);
return container;
} //-- newInstance
/**
* Sets the value of the field to a default value.
* <p>
* Reference fields are set to null, primitive fields are set to their
* default value, collection fields are emptied of all elements.
*
* @param object The object
* @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 void resetValue(final Object object) throws IllegalStateException {
_handler.resetValue(object);
}
/**
* Sets the value of the field on the object. That is, sets the value of the
* container parent to the provided value.
*
* @param object The object whose value to set.
* @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 Object value)
throws IllegalStateException, IllegalArgumentException {
if (_mode == MODE_PARENT_LINK) {
// Do nothing for MODE_PARENT_LINK; the container is not part of the object model
return;
}
// For MODE_AUTO and MODE_CHILD_LINK:
if (object instanceof ContainerElement) {
_handler.setValue(((ContainerElement) object).getParent(), value);
}
} //-- setValue
/**
* Checks the field validity. Returns successfully if the field can be
* stored, is valid, etc, throws an exception otherwise.
*
* @param object The object
* @throws ValidityException The field is invalid, is required and null, or
* any other validity violation
* @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 void checkValidity(final Object object) throws ValidityException, IllegalStateException {
//-- deprecated...do nothing
} //-- checkValidity
} //-- ContainerFieldHandler