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package javax.xml.bind;

import org.w3c.dom.Node;

import javax.xml.validation.Schema;

/**

 * Enable synchronization between XML infoset nodes and JAXB objects

 * representing same XML document.

 *

 * <p>

 * An instance of this class maintains the association between XML nodes of

 * an infoset preserving view and a JAXB representation of an XML document.

 * Navigation between the two views is provided by the methods

 * {@link #getXMLNode(Object)} and {@link #getJAXBNode(Object)}.

 *

 * <p>

 * Modifications can be made to either the infoset preserving view or the

 * JAXB representation of the document while the other view remains

 * unmodified. The binder is able to synchronize the changes made in the

 * modified view back into the other view using the appropriate

 * Binder update methods, {@link #updateXML(Object, Object)} or

 * {@link #updateJAXB(Object)}.

 *

 * <p>

 * A typical usage scenario is the following:

 * <ul>

 *   <li>load XML document into an XML infoset representation</li>

 *   <li>{@link #unmarshal(Object)} XML infoset view to JAXB view.

 *       (Note to conserve resources, it is possible to only unmarshal a

 *       subtree of the XML infoset view to the JAXB view.)</li>

 *   <li>application access/updates JAXB view of XML document.</li>

 *   <li>{@link #updateXML(Object)} synchronizes modifications to JAXB view

 *       back into the XML infoset view. Update operation preserves as

 *       much of original XML infoset as possible (i.e. comments, PI, ...)</li>

 * </ul>

 *

 * <p>

 * A Binder instance is created using the factory method

 * {@link JAXBContext#createBinder()} or {@link JAXBContext#createBinder(Class)}.

 *

 * <p>

 * The template parameter, <code>XmlNode</code>, is the

 * root interface/class for the XML infoset preserving representation.

 * A Binder implementation is required to minimally support

 * an <code>XmlNode</code> value of <code>org.w3c.dom.Node.class</code>.

 * A Binder implementation can support alternative XML infoset

 * preserving representations.

 *

 * @author

 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)

 *     Joseph Fialli

 *

 * @since 1.6, JAXB 2.0

 */

public abstract class Binder<XmlNode> {

    /**

     * Unmarshal XML infoset view to a JAXB object tree.

     *

     * <p>

     * This method is similar to {@link Unmarshaller#unmarshal(Node)}

     * with the addition of maintaining the association between XML nodes

     * and the produced JAXB objects, enabling future update operations,

     * {@link #updateXML(Object, Object)} or {@link #updateJAXB(Object)}.

     *

     * <p>

     * When {@link #getSchema()} is non-null, <code>xmlNode</code>

     * and its descendants is validated during this operation.

     *

     * <p>

     * This method throws {@link UnmarshalException} when the Binder's

     * {@link JAXBContext} does not have a mapping for the XML element name

     * or the type, specifiable via <tt>@xsi:type</tt>, of <tt>xmlNode</tt>

     * to a JAXB mapped class. The method {@link #unmarshal(Object, Class)}

     * enables an application to specify the JAXB mapped class that

     * the <tt>xmlNode</tt> should be mapped to.

     *

     * @param xmlNode

     *      the document/element to unmarshal XML data from.

     *

     * @return

     *      the newly created root object of the JAXB object tree.

     *

     * @throws JAXBException

     *      If any unexpected errors occur while unmarshalling

     * @throws UnmarshalException

     *     If the {@link ValidationEventHandler ValidationEventHandler}

     *     returns false from its <tt>handleEvent</tt> method or the

     *     <tt>Binder</tt> is unable to perform the XML to Java

     *     binding.

     * @throws IllegalArgumentException

     *      If the node parameter is null

     */

    public abstract Object unmarshal( XmlNode xmlNode ) throws JAXBException;

    /**

     * Unmarshal XML root element by provided <tt>declaredType</tt>

     * to a JAXB object tree.

     *

     * <p>

     * Implements <a href="Unmarshaller.html#unmarshalByDeclaredType">Unmarshal by Declared Type</a>

     *

     * <p>

     * This method is similar to {@link Unmarshaller#unmarshal(Node, Class)}

     * with the addition of maintaining the association between XML nodes

     * and the produced JAXB objects, enabling future update operations,

     * {@link #updateXML(Object, Object)} or {@link #updateJAXB(Object)}.

     *

     * <p>

     * When {@link #getSchema()} is non-null, <code>xmlNode</code>

     * and its descendants is validated during this operation.

     *

     * @param xmlNode

     *      the document/element to unmarshal XML data from.

     * @param declaredType

     *      appropriate JAXB mapped class to hold <tt>node</tt>'s XML data.

     *

     * @return

     * <a href="JAXBElement.html">JAXB Element</a> representation

     * of <tt>node</tt>

     *

     * @throws JAXBException

     *      If any unexpected errors occur while unmarshalling

     * @throws UnmarshalException

     *     If the {@link ValidationEventHandler ValidationEventHandler}

     *     returns false from its <tt>handleEvent</tt> method or the

     *     <tt>Binder</tt> is unable to perform the XML to Java

     *     binding.

     * @throws IllegalArgumentException

     *      If any of the input parameters are null

     * @since 1.6, JAXB 2.0

     */

    public abstract <T> JAXBElement<T>

        unmarshal( XmlNode xmlNode, Class<T> declaredType )

        throws JAXBException;

    /**

     * Marshal a JAXB object tree to a new XML document.

     *

     * <p>

     * This method is similar to {@link Marshaller#marshal(Object, Node)}

     * with the addition of maintaining the association between JAXB objects

     * and the produced XML nodes,

     * enabling future update operations such as

     * {@link #updateXML(Object, Object)} or {@link #updateJAXB(Object)}.

     *

     * <p>

     * When {@link #getSchema()} is non-null, the marshalled

     * xml content is validated during this operation.

     *

     * @param jaxbObject

     *      The content tree to be marshalled.

     * @param xmlNode

     *      The parameter must be a Node that accepts children.

     *

     * @throws JAXBException

     *      If any unexpected problem occurs during the marshalling.

     * @throws MarshalException

     *      If the {@link ValidationEventHandler ValidationEventHandler}

     *      returns false from its <tt>handleEvent</tt> method or the

     *      <tt>Binder</tt> is unable to marshal <tt>jaxbObject</tt> (or any

     *      object reachable from <tt>jaxbObject</tt>).

     *

     * @throws IllegalArgumentException

     *      If any of the method parameters are null

     */

    public abstract void marshal( Object jaxbObject, XmlNode xmlNode ) throws JAXBException;

    /**

     * Gets the XML element associated with the given JAXB object.

     *

     * <p>

     * Once a JAXB object tree is associated with an XML fragment,

     * this method enables navigation between the two trees.

     *

     * <p>

     * An association between an XML element and a JAXB object is

     * established by the bind methods and the update methods.

     * Note that this association is partial; not all XML elements

     * have associated JAXB objects, and not all JAXB objects have

     * associated XML elements.

     *

     * @param jaxbObject An instance that is reachable from a prior

     *                   call to a bind or update method that returned

     *                   a JAXB object tree.

     *

     * @return

     *      null if the specified JAXB object is not known to this

     *      {@link Binder}, or if it is not associated with an

     *      XML element.

     *

     * @throws IllegalArgumentException

     *      If the jaxbObject parameter is null

     */

    public abstract XmlNode getXMLNode( Object jaxbObject );

    /**

     * Gets the JAXB object associated with the given XML element.

     *

     * <p>

     * Once a JAXB object tree is associated with an XML fragment,

     * this method enables navigation between the two trees.

     *

     * <p>

     * An association between an XML element and a JAXB object is

     * established by the unmarshal, marshal and update methods.

     * Note that this association is partial; not all XML elements

     * have associated JAXB objects, and not all JAXB objects have

     * associated XML elements.

     *

     * @return

     *      null if the specified XML node is not known to this

     *      {@link Binder}, or if it is not associated with a

     *      JAXB object.

     *

     * @throws IllegalArgumentException

     *      If the node parameter is null

     */

    public abstract Object getJAXBNode( XmlNode xmlNode );

    /**

     * Takes an JAXB object and updates

     * its associated XML node and its descendants.

     *

     * <p>

     * This is a convenience method of:

     * <pre>

     * updateXML( jaxbObject, getXMLNode(jaxbObject));

     * </pre>

     *

     * @throws JAXBException

     *      If any unexpected problem occurs updating corresponding XML content.

     * @throws IllegalArgumentException

     *      If the jaxbObject parameter is null

     */

    public abstract XmlNode updateXML( Object jaxbObject ) throws JAXBException;

    /**

     * Changes in JAXB object tree are updated in its associated XML parse tree.

     *

     * <p>

     * This operation can be thought of as an "in-place" marshalling.

     * The difference is that instead of creating a whole new XML tree,

     * this operation updates an existing tree while trying to preserve

     * the XML as much as possible.

     *

     * <p>

     * For example, unknown elements/attributes in XML that were not bound

     * to JAXB will be left untouched (whereas a marshalling operation

     * would create a new tree that doesn't contain any of those.)

     *

     * <p>

     * As a side-effect, this operation updates the association between

     * XML nodes and JAXB objects.

     *

     * @param jaxbObject root of potentially modified JAXB object tree

     * @param xmlNode    root of update target XML parse tree

     *

     * @return

     *      Returns the updated XML node. Typically, this is the same

     *      node you passed in as <i>xmlNode</i>, but it maybe

     *      a different object, for example when the tag name of the object

     *      has changed.

     *

     * @throws JAXBException

     *      If any unexpected problem occurs updating corresponding XML content.

     * @throws IllegalArgumentException

     *      If any of the input parameters are null

     */

    public abstract XmlNode updateXML( Object jaxbObject, XmlNode xmlNode ) throws JAXBException;

    /**

     * Takes an XML node and updates its associated JAXB object and its descendants.

     *

     * <p>

     * This operation can be thought of as an "in-place" unmarshalling.

     * The difference is that instead of creating a whole new JAXB tree,

     * this operation updates an existing tree, reusing as much JAXB objects

     * as possible.

     *

     * <p>

     * As a side-effect, this operation updates the association between

     * XML nodes and JAXB objects.

     *

     * @return

     *      Returns the updated JAXB object. Typically, this is the same

     *      object that was returned from earlier

     *      {@link #marshal(Object,Object)} or

     *      {@link #updateJAXB(Object)} method invocation,

     *      but it maybe

     *      a different object, for example when the name of the XML

     *      element has changed.

     *

     * @throws JAXBException

     *      If any unexpected problem occurs updating corresponding JAXB mapped content.

     * @throws IllegalArgumentException

     *      If node parameter is null

     */

    public abstract Object updateJAXB( XmlNode xmlNode ) throws JAXBException;

    /**

     * Specifies whether marshal, unmarshal and update methods

     * performs validation on their XML content.

     *

     * @param schema set to null to disable validation.

     *

     * @see Unmarshaller#setSchema(Schema)

     */

    public abstract void setSchema( Schema schema );

    /**

     * Gets the last {@link Schema} object (including null) set by the

     * {@link #setSchema(Schema)} method.

     *

     * @return the Schema object for validation or null if not present

     */

    public abstract Schema getSchema();

    /**

     * Allow an application to register a <tt>ValidationEventHandler</tt>.

     * <p>

     * The <tt>ValidationEventHandler</tt> will be called by the JAXB Provider

     * if any validation errors are encountered during calls to any of the

     * Binder unmarshal, marshal and update methods.

     *

     * <p>

     * Calling this method with a null parameter will cause the Binder

     * to revert back to the default default event handler.

     *

     * @param handler the validation event handler

     * @throws JAXBException if an error was encountered while setting the

     *         event handler

     */

    public abstract void setEventHandler( ValidationEventHandler handler ) throws JAXBException;

    /**

     * Return the current event handler or the default event handler if one

     * hasn't been set.

     *

     * @return the current ValidationEventHandler or the default event handler

     *         if it hasn't been set

     * @throws JAXBException if an error was encountered while getting the

     *         current event handler

     */

    public abstract ValidationEventHandler getEventHandler() throws JAXBException;

    /**

     *

     * Set the particular property in the underlying implementation of

     * <tt>Binder</tt>.  This method can only be used to set one of

     * the standard JAXB defined unmarshal/marshal properties

     * or a provider specific property for binder, unmarshal or marshal.

     * Attempting to set an undefined property will result in

     * a PropertyException being thrown.  See

     * <a href="Unmarshaller.html#supportedProps">Supported Unmarshal Properties</a>

     * and

     * <a href="Marshaller.html#supportedProps">Supported Marshal Properties</a>.

     *

     * @param name the name of the property to be set. This value can either

     *              be specified using one of the constant fields or a user

     *              supplied string.

     * @param value the value of the property to be set

     *

     * @throws PropertyException when there is an error processing the given

     *                            property or value

     * @throws IllegalArgumentException

     *      If the name parameter is null

     */

    abstract public void setProperty( String name, Object value ) throws PropertyException;

    /**

     * Get the particular property in the underlying implementation of

     * <tt>Binder</tt>.  This method can only

     * be used to get one of

     * the standard JAXB defined unmarshal/marshal properties

     * or a provider specific property for binder, unmarshal or marshal.

     * Attempting to get an undefined property will result in

     * a PropertyException being thrown.  See

     * <a href="Unmarshaller.html#supportedProps">Supported Unmarshal Properties</a>

     * and

     * <a href="Marshaller.html#supportedProps">Supported Marshal Properties</a>.

     *

     * @param name the name of the property to retrieve

     * @return the value of the requested property

     *

     * @throws PropertyException

     *      when there is an error retrieving the given property or value

     *      property name

     * @throws IllegalArgumentException

     *      If the name parameter is null

     */

    abstract public Object getProperty( String name ) throws PropertyException;

}