194 lines
6.7 KiB
Java
194 lines
6.7 KiB
Java
/*
|
|
* Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation. Oracle designates this
|
|
* particular file as subject to the "Classpath" exception as provided
|
|
* by Oracle in the LICENSE file that accompanied this code.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
package javax.xml.bind.annotation.adapters;
|
|
|
|
/**
|
|
* Adapts a Java type for custom marshaling.
|
|
*
|
|
* <p> <b> Usage: </b> </p>
|
|
*
|
|
* <p>
|
|
* Some Java types do not map naturally to a XML representation, for
|
|
* example <tt>HashMap</tt> or other non JavaBean classes. Conversely,
|
|
* a XML repsentation may map to a Java type but an application may
|
|
* choose to accesss the XML representation using another Java
|
|
* type. For example, the schema to Java binding rules bind
|
|
* xs:DateTime by default to XmlGregorianCalendar. But an application
|
|
* may desire to bind xs:DateTime to a custom type,
|
|
* MyXmlGregorianCalendar, for example. In both cases, there is a
|
|
* mismatch between <i> bound type </i>, used by an application to
|
|
* access XML content and the <i> value type</i>, that is mapped to an
|
|
* XML representation.
|
|
*
|
|
* <p>
|
|
* This abstract class defines methods for adapting a bound type to a value
|
|
* type or vice versa. The methods are invoked by the JAXB binding
|
|
* framework during marshaling and unmarshalling:
|
|
*
|
|
* <ul>
|
|
* <li> <b> XmlAdapter.marshal(...): </b> During marshalling, JAXB
|
|
* binding framework invokes XmlAdapter.marshal(..) to adapt a
|
|
* bound type to value type, which is then marshaled to XML
|
|
* representation. </li>
|
|
*
|
|
* <li> <b> XmlAdapter.unmarshal(...): </b> During unmarshalling,
|
|
* JAXB binding framework first unmarshals XML representation
|
|
* to a value type and then invokes XmlAdapter.unmarshal(..) to
|
|
* adapt the value type to a bound type. </li>
|
|
* </ul>
|
|
*
|
|
* Writing an adapter therefore involves the following steps:
|
|
*
|
|
* <ul>
|
|
* <li> Write an adapter that implements this abstract class. </li>
|
|
* <li> Install the adapter using the annotation {@link
|
|
* XmlJavaTypeAdapter} </li>
|
|
* </ul>
|
|
*
|
|
* <p><b>Example:</b> Customized mapping of <tt>HashMap</tt></p>
|
|
* <p> The following example illustrates the use of
|
|
* <tt>@XmlAdapter</tt> and <tt>@XmlJavaTypeAdapter</tt> to
|
|
* customize the mapping of a <tt>HashMap</tt>.
|
|
*
|
|
* <p> <b> Step 1: </b> Determine the desired XML representation for HashMap.
|
|
*
|
|
* <pre>
|
|
* <hashmap>
|
|
* <entry key="id123">this is a value</entry>
|
|
* <entry key="id312">this is another value</entry>
|
|
* ...
|
|
* </hashmap>
|
|
* </pre>
|
|
*
|
|
* <p> <b> Step 2: </b> Determine the schema definition that the
|
|
* desired XML representation shown above should follow.
|
|
*
|
|
* <pre>
|
|
*
|
|
* <xs:complexType name="myHashMapType">
|
|
* <xs:sequence>
|
|
* <xs:element name="entry" type="myHashMapEntryType"
|
|
* minOccurs = "0" maxOccurs="unbounded"/>
|
|
* </xs:sequence>
|
|
* </xs:complexType>
|
|
*
|
|
* <xs:complexType name="myHashMapEntryType">
|
|
* <xs:simpleContent>
|
|
* <xs:extension base="xs:string">
|
|
* <xs:attribute name="key" type="xs:int"/>
|
|
* </xs:extension>
|
|
* </xs:simpleContent>
|
|
* </xs:complexType>
|
|
*
|
|
* </pre>
|
|
*
|
|
* <p> <b> Step 3: </b> Write value types that can generate the above
|
|
* schema definition.
|
|
*
|
|
* <pre>
|
|
* public class MyHashMapType {
|
|
* List<MyHashMapEntryType> entry;
|
|
* }
|
|
*
|
|
* public class MyHashMapEntryType {
|
|
* @XmlAttribute
|
|
* public Integer key;
|
|
*
|
|
* @XmlValue
|
|
* public String value;
|
|
* }
|
|
* </pre>
|
|
*
|
|
* <p> <b> Step 4: </b> Write the adapter that adapts the value type,
|
|
* MyHashMapType to a bound type, HashMap, used by the application.
|
|
*
|
|
* <pre>
|
|
* public final class MyHashMapAdapter extends
|
|
* XmlAdapter<MyHashMapType,HashMap> { ... }
|
|
*
|
|
* </pre>
|
|
*
|
|
* <p> <b> Step 5: </b> Use the adapter.
|
|
*
|
|
* <pre>
|
|
* public class Foo {
|
|
* @XmlJavaTypeAdapter(MyHashMapAdapter.class)
|
|
* HashMap hashmap;
|
|
* ...
|
|
* }
|
|
* </pre>
|
|
*
|
|
* The above code fragment will map to the following schema:
|
|
*
|
|
* <pre>
|
|
* <xs:complexType name="Foo">
|
|
* <xs:sequence>
|
|
* <xs:element name="hashmap" type="myHashMapType"
|
|
* </xs:sequence>
|
|
* </xs:complexType>
|
|
* </pre>
|
|
*
|
|
* @param <BoundType>
|
|
* The type that JAXB doesn't know how to handle. An adapter is written
|
|
* to allow this type to be used as an in-memory representation through
|
|
* the <tt>ValueType</tt>.
|
|
* @param <ValueType>
|
|
* The type that JAXB knows how to handle out of the box.
|
|
*
|
|
* @author <ul><li>Sekhar Vajjhala, Sun Microsystems Inc.</li> <li> Kohsuke Kawaguchi, Sun Microsystems Inc.</li></ul>
|
|
* @see XmlJavaTypeAdapter
|
|
* @since JAXB 2.0
|
|
*/
|
|
public abstract class XmlAdapter<ValueType,BoundType> {
|
|
|
|
/**
|
|
* Do-nothing constructor for the derived classes.
|
|
*/
|
|
protected XmlAdapter() {}
|
|
|
|
/**
|
|
* Convert a value type to a bound type.
|
|
*
|
|
* @param v
|
|
* The value to be converted. Can be null.
|
|
* @throws Exception
|
|
* if there's an error during the conversion. The caller is responsible for
|
|
* reporting the error to the user through {@link javax.xml.bind.ValidationEventHandler}.
|
|
*/
|
|
public abstract BoundType unmarshal(ValueType v) throws Exception;
|
|
|
|
/**
|
|
* Convert a bound type to a value type.
|
|
*
|
|
* @param v
|
|
* The value to be convereted. Can be null.
|
|
* @throws Exception
|
|
* if there's an error during the conversion. The caller is responsible for
|
|
* reporting the error to the user through {@link javax.xml.bind.ValidationEventHandler}.
|
|
*/
|
|
public abstract ValueType marshal(BoundType v) throws Exception;
|
|
}
|