/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
* [name of copyright owner]"
*
* Contributor(s):
*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.xml.internal.bind.marshaller;
import java.io.OutputStream;
import javax.xml.bind.JAXBContext;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.transform.dom.DOMResult;
import org.w3c.dom.Node;
// be careful about changing this class. this class is supposed to be
// extended by users and therefore we are not allowed to break
// those user code.
//
// this means:
// - don't add any abstract method
// - don't change any existing method signature
// - don't remove any existing method.
/**
* Implemented by the user application to determine URI -> prefix mapping.
*
* This is considered as an interface, though it's implemented as an abstract
* class to make it easy to add new methods in a future.
*
* @author Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
*/
public abstract class NamespacePrefixMapper {
private static final String[] EMPTY_STRING = new String[0];
/**
* Returns a preferred prefix for the given namespace URI.
*
* This method is intended to be overrided by a derived class.
*
*
* <p>
* As noted in the return value portion of the javadoc, there are several
* cases where the preference cannot be honored. Specifically, as of JAXB RI
* 2.0 and onward:
*
* <ol>
* <li>
* If the prefix returned is already in use as one of the in-scope namespace
* bindings. This is partly necessary for correctness (so that we don't
* unexpectedly change the meaning of QNames bound to {@link String}),
* partly to simplify the marshaller.
* <li>
* If the prefix returned is "" yet the current {@link JAXBContext} includes
* classes that use the empty namespace URI. This allows the JAXB RI to
* reserve the "" prefix for the empty namespace URI, which is the only
* possible prefix for the URI. This restriction is also to simplify the
* marshaller.
* </ol>
*
* @param namespaceUri
* The namespace URI for which the prefix needs to be found.
* Never be null. "" is used to denote the default namespace.
* @param suggestion
* When the content tree has a suggestion for the prefix to the
* given namespaceUri, that suggestion is passed as a parameter.
* Typicall this value comes from the QName.getPrefix to show the
* preference of the content tree. This parameter may be null,
* and this parameter may represent an already occupied prefix.
* @param requirePrefix
* If this method is expected to return non-empty prefix. When
* this flag is true, it means that the given namespace URI
* cannot be set as the default namespace.
*
* @return null if there's no prefered prefix for the namespace URI. In this
* case, the system will generate a prefix for you.
*
* Otherwise the system will try to use the returned prefix, but
* generally there's no guarantee if the prefix will be actually
* used or not.
*
* return "" to map this namespace URI to the default namespace.
* Again, there's no guarantee that this preference will be honored.
*
* If this method returns "" when requirePrefix=true, the return
* value will be ignored and the system will generate one.
*
* @since JAXB 1.0.1
*/
public abstract String getPreferredPrefix(String namespaceUri, String suggestion, boolean requirePrefix);
/**
* Returns a list of namespace URIs that should be declared at the root
* element.
*
* <p>
* By default, the JAXB RI 1.0.x produces namespace declarations only when
* they are necessary, only at where they are used. Because of this lack of
* look-ahead, sometimes the marshaller produces a lot of namespace
* declarations that look redundant to human eyes. For example,
*
* <pre>
* <xmp>
* <?xml version="1.0"?>
* <root>
* <ns1:child xmlns:ns1="urn:foo"> ... </ns1:child>
* <ns2:child xmlns:ns2="urn:foo"> ... </ns2:child>
* <ns3:child xmlns:ns3="urn:foo"> ... </ns3:child>
* ...
* </root>
* </xmp>
* </pre>
*
* <p>
* The JAXB RI 2.x mostly doesn't exhibit this behavior any more, as it
* declares all statically known namespace URIs (those URIs that are used as
* element/attribute names in JAXB annotations), but it may still declare
* additional namespaces in the middle of a document, for example when (i) a
* QName as an attribute/element value requires a new namespace URI, or (ii)
* DOM nodes as a portion of an object tree requires a new namespace URI.
*
* <p>
* If you know in advance that you are going to use a certain set of
* namespace URIs, you can override this method and have the marshaller
* declare those namespace URIs at the root element.
*
* <p>
* For example, by returning <code>new String[]{"urn:foo"}</code>, the
* marshaller will produce:
*
* <pre>
* <xmp>
* <?xml version="1.0"?>
* <root xmlns:ns1="urn:foo">
* <ns1:child> ... </ns1:child>
* <ns1:child> ... </ns1:child>
* <ns1:child> ... </ns1:child>
* ...
* </root>
* </xmp>
* </pre>
* <p>
* To control prefixes assigned to those namespace URIs, use the
* {@link #getPreferredPrefix(String, String, boolean)} method.
*
* @return A list of namespace URIs as an array of {@link String}s. This
* method can return a length-zero array but not null. None of the
* array component can be null. To represent the empty namespace,
* use the empty string <code>""</code>.
*
* @since JAXB RI 1.0.2
*/
public String[] getPreDeclaredNamespaceUris() {
return EMPTY_STRING;
}
/**
* Similar to {@link #getPreDeclaredNamespaceUris()} but allows the
* (prefix,nsUri) pairs to be returned.
*
* <p>
* With {@link #getPreDeclaredNamespaceUris()}, applications who wish to
* control the prefixes as well as the namespaces needed to implement both
* {@link #getPreDeclaredNamespaceUris()} and
* {@link #getPreferredPrefix(String, String, boolean)}.
*
* <p>
* This version eliminates the needs by returning an array of pairs.
*
* @return always return a non-null (but possibly empty) array. The array
* stores data like (prefix1,nsUri1,prefix2,nsUri2,...) Use an empty
* string to represent the empty namespace URI and the default
* prefix. Null is not allowed as a value in the array.
*
* @since JAXB RI 2.0 beta
*/
public String[] getPreDeclaredNamespaceUris2() {
return EMPTY_STRING;
}
/**
* Returns a list of (prefix,namespace URI) pairs that represents namespace
* bindings available on ancestor elements (that need not be repeated by the
* JAXB RI.)
*
* <p>
* Sometimes JAXB is used to marshal an XML document, which will be used as
* a subtree of a bigger document. When this happens, it's nice for a JAXB
* marshaller to be able to use in-scope namespace bindings of the larger
* document and avoid declaring redundant namespace URIs.
*
* <p>
* This is automatically done when you are marshalling to
* {@link XMLStreamWriter}, {@link XMLEventWriter}, {@link DOMResult}, or
* {@link Node}, because those output format allows us to inspect what's
* currently available as in-scope namespace binding. However, with other
* output format, such as {@link OutputStream}, the JAXB RI cannot do this
* automatically. That's when this method comes into play.
*
* <p>
* Namespace bindings returned by this method will be used by the JAXB RI,
* but will not be re-declared. They are assumed to be available when you
* insert this subtree into a bigger document.
*
* <p>
* It is <b>NOT</b> OK to return the same binding, or give the receiver a
* conflicting binding information. It's a responsibility of the caller to
* make sure that this doesn't happen even if the ancestor elements look
* like:
*
* <pre>
* <xmp>
* <foo:abc xmlns:foo="abc">
* <foo:abc xmlns:foo="def">
* <foo:abc xmlns:foo="abc">
* ... JAXB marshalling into here.
* </foo:abc>
* </foo:abc>
* </foo:abc>
* </xmp>
* </pre>
*
*
* @return always return a non-null (but possibly empty) array. The array
* stores data like (prefix1,nsUri1,prefix2,nsUri2,...) Use an empty
* string to represent the empty namespace URI and the default
* prefix. Null is not allowed as a value in the array.
*
* @since JAXB RI 2.0 beta
*/
public String[] getContextualNamespaceDecls() {
return EMPTY_STRING;
}
}