/*
* $Id: StartElementEvent.java,v 1.5 2004/07/15 02:11:01 cniles Exp $
*
* Copyright (c) 2004, Christian Niles, unit12.net
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of Christian Niles, Unit12, nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 THE COPYRIGHT OWNER OR 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.
*
*/
package javanet.staxutils.events;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.events.Attribute;
import javax.xml.stream.events.Namespace;
import javax.xml.stream.events.StartElement;
import javanet.staxutils.NamespaceContextAdapter;
import javanet.staxutils.StaticNamespaceContext;
/**
* {@link StartElement} event implementation. This event will coalesce its namespaces
* into an internal {@link NamespaceContext}, available via
* {@link #getNamespaceContext()}. It will also create any implicit namespaces
* necessary to satisfy the element's name and those of its attributes.
*
* @author Christian Niles
* @version $Revision: 1.5 $
*/
public class StartElementEvent extends AbstractXMLEvent implements StartElement {
/** The qualified element name. */
protected QName name;
/** The element attributes. */
protected Map attributes;
/** The element namespaces. */
protected Map namespaces;
/** The namespace context. */
protected NamespaceContext namespaceCtx;
public StartElementEvent(QName name, NamespaceContext namespaceCtx,
Location location) {
super(location);
this.name = name;
this.namespaceCtx = new StartElementContext(namespaceCtx);
}
public StartElementEvent(QName name, Iterator attributes,
Iterator namespaces, NamespaceContext namespaceCtx,
Location location, QName schemaType) {
super(location, schemaType);
this.namespaceCtx = new StartElementContext(namespaceCtx);
mergeNamespaces(namespaces);
mergeAttributes(attributes);
QName newName = processQName(name);
this.name = (newName == null ? name : newName);
}
public StartElementEvent(StartElement that) {
this(that.getName(),
that.getAttributes(),
that.getNamespaces(),
that.getNamespaceContext(),
that.getLocation(),
that.getSchemaType());
}
/** Returns {@link #START_ELEMENT}. */
public int getEventType() {
return START_ELEMENT;
}
public QName getName() {
return name;
}
public Attribute getAttributeByName(QName name) {
if (attributes != null) {
return (Attribute) attributes.get(name);
} else {
return null;
}
}
public Iterator getAttributes() {
if (attributes != null) {
return attributes.values().iterator();
} else {
return Collections.EMPTY_LIST.iterator();
}
}
public NamespaceContext getNamespaceContext() {
return namespaceCtx;
}
public Iterator getNamespaces() {
if (namespaces != null) {
return namespaces.values().iterator();
} else {
return Collections.EMPTY_LIST.iterator();
}
}
public String getNamespaceURI(String prefix) {
return getNamespaceContext().getNamespaceURI(prefix);
}
/**
* Performs the task of adding {@link Attribute}s into the internal
* {@link #attributes} map. Along the way, it will also create the necessary
* {@link Namespace} events to satisfy attribute namespaces.
*
* @param iter An iterator over a set of {@link Attributes}.
*/
private void mergeAttributes(Iterator iter) {
if (iter == null) {
return;
}
while (iter.hasNext()) {
Attribute attr = (Attribute) iter.next();
if (attributes == null) {
attributes = new HashMap();
}
// check if the attribute QName has the proper mapping
QName attrName = attr.getName();
QName newName = processQName(attrName);
if (newName != null) {
// need to generate a new attribute with the new qualified name
Attribute newAttr = new AttributeEvent(newName, null, attr);
attributes.put(newName, newAttr);
} else {
// the attribute is fine
attributes.put(attrName, attr);
}
}
}
/**
* Performs the task of adding {@link Namespace}s into the internal
* {@link #namespaces} map.
*
* @param iter An iterator over a set of {@link Namespaces}.
*/
private void mergeNamespaces(Iterator iter) {
if (iter == null) {
return;
}
// for each namespace, add it to the context, and place it in the list
while (iter.hasNext()) {
Namespace ns = (Namespace) iter.next();
String prefix = ns.getPrefix();
if (namespaces == null) {
namespaces = new HashMap();
}
if (!namespaces.containsKey(prefix)) {
namespaces.put(prefix, ns);
}
}
}
/**
* Processes a {@link QName}, possibly rewriting it to match the current
* namespace context. If necessary, a new {@link Namespace} will be added to
* support the name's prefix.
*
* @param name The {@link QName} to process.
* @return The new name, or <code>null</code> if no changes were necessary.
*/
private QName processQName(QName name) {
String nsURI = name.getNamespaceURI();
String prefix = name.getPrefix();
if (nsURI == null || nsURI.length() == 0) {
// name belongs to no namespace. This can only be okay if the name is
// an attribute name, or the default namespace hasn't been overridden.
// either way, no prefix should be allowed on the name, so the best we
// can do is rewrite the name to make sure no prefix is present
// clear any prefix from the name
if (prefix != null && prefix.length() > 0) {
return new QName(name.getLocalPart());
} else {
return name;
}
}
// namespace uri is non-null after this point
String resolvedNS = namespaceCtx.getNamespaceURI(prefix);
if (resolvedNS == null) {
// if the prefix is not empty, then we should default the prefix
if (prefix != null && prefix.length() > 0) {
if (namespaces == null) {
namespaces = new HashMap();
}
namespaces.put(prefix, new NamespaceEvent(prefix, nsURI));
}
return null;
} else if (!resolvedNS.equals(nsURI)) {
// The prefix is bound to a different namespace, so we'll have to
// search for existing prefixes bound to the namespace uri, or
// generate a new namespace binding.
String newPrefix = namespaceCtx.getPrefix(nsURI);
if (newPrefix == null) {
// no existing prefix; need to generate a new prefix
newPrefix = generatePrefix(nsURI);
}
// return the newly prefixed name
return new QName(nsURI, name.getLocalPart(), newPrefix);
} else {
// prefix has already been bound to the namespace; nothing to do
return null;
}
}
/**
* Generates a new namespace prefix for the specified namespace URI that
* doesn't collide with any existing prefix.
*
* @param nsURI The URI for which to generate a prefix.
* @return The new prefix.
*/
private String generatePrefix(String nsURI) {
String newPrefix;
int nsCount = 0;
do {
newPrefix = "ns" + nsCount;
nsCount++;
} while (namespaceCtx.getNamespaceURI(newPrefix) != null);
if (namespaces == null) {
namespaces = new HashMap();
}
namespaces.put(newPrefix, new NamespaceEvent(newPrefix, nsURI));
return newPrefix;
}
/**
* Adapts another {@link NamespaceContext} to expose this tag's declared
* namespaces.
*
* @author Christian Niles
* @version $Revision: 1.5 $
*/
private final class StartElementContext extends NamespaceContextAdapter
implements
StaticNamespaceContext {
public StartElementContext(NamespaceContext namespaceCtx) {
super(namespaceCtx);
}
public String getNamespaceURI(String prefix) {
if (namespaces != null && namespaces.containsKey(prefix)) {
Namespace namespace = (Namespace) namespaces.get(prefix);
return namespace.getNamespaceURI();
} else {
return super.getNamespaceURI(prefix);
}
}
public String getPrefix(String nsURI) {
for (Iterator i = getNamespaces(); i.hasNext();) {
Namespace ns = (Namespace) i.next();
if (ns.getNamespaceURI().equals(nsURI)) {
return ns.getPrefix();
}
}
return super.getPrefix(nsURI);
}
public Iterator getPrefixes(String nsURI) {
// lazily-loaded set to store found prefixes
List prefixes = null;
// add our prefixes first
if (namespaces != null) {
for (Iterator i = namespaces.values().iterator(); i.hasNext();) {
Namespace ns = (Namespace) i.next();
if (ns.getNamespaceURI().equals(nsURI)) {
if (prefixes == null) {
prefixes = new ArrayList();
}
String prefix = ns.getPrefix();
prefixes.add(prefix);
}
}
}
// copy parent prefixes that aren't redefined by this context
Iterator parentPrefixes = super.getPrefixes(nsURI);
while (parentPrefixes.hasNext()) {
String prefix = (String) parentPrefixes.next();
// only add the prefix if we haven't redefined it
if (namespaces != null && !namespaces.containsKey(prefix)) {
if (prefixes == null) {
prefixes = new ArrayList();
}
prefixes.add(prefix);
}
}
return prefixes == null
? Collections.EMPTY_LIST.iterator()
: prefixes.iterator();
}
}
}