/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.tuscany.sca.contribution.processor;
import static javax.xml.stream.XMLStreamConstants.END_ELEMENT;
import static javax.xml.stream.XMLStreamConstants.START_ELEMENT;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import org.apache.tuscany.sca.assembly.AssemblyFactory;
import org.apache.tuscany.sca.assembly.Extensible;
import org.apache.tuscany.sca.assembly.Extension;
import org.apache.tuscany.sca.common.xml.stax.StAXHelper;
/**
* A base class with utility methods for the other artifact processors in this module.
*
* @version $Rev: 937321 $ $Date: 2010-04-23 16:01:54 +0100 (Fri, 23 Apr 2010) $
* @tuscany.spi.extension.inheritfrom
*/
public abstract class BaseStAXArtifactProcessor {
private static String SCA11_NS = "http://docs.oasis-open.org/ns/opencsa/sca/200912";
private static String SCA11_TUSCANY_NS = "http://tuscany.apache.org/xmlns/sca/1.1";
/**
* The StAXHelper without states
*/
private static final StAXHelper helper = new StAXHelper(null, null, null);
/**
* Returns a QName from a string.
* @param reader
* @param value
* @return
*/
protected QName getQNameValue(XMLStreamReader reader, String value) {
return StAXHelper.getValueAsQName(reader, value);
}
/**
* Returns the boolean value of an attribute.
* @param reader
* @param name
* @return
*/
protected boolean getBoolean(XMLStreamReader reader, String name) {
Boolean attr = StAXHelper.getAttributeAsBoolean(reader, name);
if (attr == null) {
return false;
} else {
return attr.booleanValue();
}
}
/**
* Returns the QName value of an attribute.
* @param reader
* @param name
* @return
*/
protected QName getQName(XMLStreamReader reader, String name) {
return StAXHelper.getAttributeAsQName(reader, name);
}
/**
* Returns the value of an attribute as a list of QNames.
* @param reader
* @param name
* @return
*/
protected List<QName> getQNames(XMLStreamReader reader, String name) {
return StAXHelper.getAttributeAsQNames(reader, name);
}
/**
* Returns the string value of an attribute.
* @param reader
* @param name
* @return
*/
protected String getString(XMLStreamReader reader, String name) {
return StAXHelper.getAttributeAsString(reader, name);
}
/**
* Returns the string value of an attribute.
* @param reader
* @param name
* @return
*/
protected String getURIString(XMLStreamReader reader, String name) {
return StAXHelper.getAttributeAsURIString(reader, name);
}
/**
* Test if an attribute is explicitly set
* @param reader
* @param name
* @return
*/
protected boolean isSet(XMLStreamReader reader, String name) {
return StAXHelper.isAttributePresent(reader, name);
}
/**
* Returns the value of xsi:type attribute
* @param reader The XML stream reader
* @return The QName of the type, if the attribute is not present, null is
* returned.
*/
protected QName getXSIType(XMLStreamReader reader) {
return StAXHelper.getXSIType(reader);
}
/**
* Parse the next child element.
* @param reader
* @return
* @throws XMLStreamException
*/
protected boolean nextChildElement(XMLStreamReader reader) throws XMLStreamException {
while (reader.hasNext()) {
int event = reader.next();
if (event == END_ELEMENT) {
return false;
}
if (event == START_ELEMENT) {
return true;
}
}
return false;
}
/**
* Advance the stream to the next END_ELEMENT event skipping any nested
* content.
* @param reader the reader to advance
* @throws XMLStreamException if there was a problem reading the stream
*/
protected void skipToEndElement(XMLStreamReader reader) throws XMLStreamException {
StAXHelper.skipToEndElement(reader);
}
/**
*
* @param writer
* @param uri
* @throws XMLStreamException
*/
private String setPrefix(XMLStreamWriter writer, String uri) throws XMLStreamException {
if (uri == null) {
return null;
}
String prefix = writer.getPrefix(uri);
if (prefix != null) {
return null;
} else {
// Find an available prefix and bind it to the given URI
NamespaceContext nsc = writer.getNamespaceContext();
for (int i=1; ; i++) {
prefix = "ns" + i;
if (nsc.getNamespaceURI(prefix) == null) {
break;
}
}
writer.setPrefix(prefix, uri);
return prefix;
}
}
/**
* Start an element.
* @param uri
* @param name
* @param attrs
* @throws XMLStreamException
*/
protected void writeStart(XMLStreamWriter writer, String uri, String name, XAttr... attrs)
throws XMLStreamException {
helper.writeStartElement(writer, "", name, uri);
writeAttributes(writer, attrs);
}
/**
* Start an element.
* @param qname
* @param attrs
* @throws XMLStreamException
*/
protected void writeStart(XMLStreamWriter writer, QName qname, XAttr... attrs) throws XMLStreamException {
writeStart(writer, qname.getNamespaceURI(), qname.getLocalPart(), attrs);
}
/**
* End an element.
* @param writer
* @throws XMLStreamException
*/
protected void writeEnd(XMLStreamWriter writer) throws XMLStreamException {
writer.writeEndElement();
}
/**
* Start a document.
* @param writer
* @throws XMLStreamException
*/
protected void writeStartDocument(XMLStreamWriter writer, String uri, String name, XAttr... attrs) throws XMLStreamException {
writer.writeStartDocument();
writer.setDefaultNamespace(uri);
writeStart(writer, uri, name, attrs);
// writer.writeDefaultNamespace(uri);
}
/**
* Start a document.
* @param writer
* @param qname
* @param attrs
* @throws XMLStreamException
*/
protected void writeStartDocument(XMLStreamWriter writer, QName qname, XAttr... attrs) throws XMLStreamException {
writeStartDocument(writer, qname.getNamespaceURI(), qname.getLocalPart(), attrs);
}
/**
* End a document.
* @param writer
* @throws XMLStreamException
*/
protected void writeEndDocument(XMLStreamWriter writer) throws XMLStreamException {
writer.writeEndDocument();
}
/**
* Write attributes to the current element.
* @param writer
* @param attrs
* @throws XMLStreamException
*/
protected void writeAttributes(XMLStreamWriter writer, XAttr... attrs) throws XMLStreamException {
for (XAttr attr : attrs) {
if (attr != null)
attr.write(writer);
}
}
/**
*
* @param reader
* @param extensible
* @param extensionAttributeProcessor
* @param extensionAttributeProcessor
* @param extensionFactory
* @param context TODO
* @param elementName
* @throws ContributionReadException
* @throws XMLStreamException
*/
protected void readExtendedAttributes(XMLStreamReader reader,
Extensible extensible,
StAXAttributeProcessor extensionAttributeProcessor,
AssemblyFactory extensionFactory, ProcessorContext context) throws ContributionReadException,
XMLStreamException {
QName elementName = reader.getName();
for (int a = 0; a < reader.getAttributeCount(); a++) {
QName attributeName = reader.getAttributeName(a);
if (attributeName.getNamespaceURI() != null && attributeName.getNamespaceURI().length() > 0) {
if (!elementName.getNamespaceURI().equals(attributeName.getNamespaceURI())) {
Object attributeValue = extensionAttributeProcessor.read(attributeName, reader, context);
Extension attributeExtension;
if (attributeValue instanceof Extension) {
attributeExtension = (Extension)attributeValue;
} else {
attributeExtension = extensionFactory.createExtension();
attributeExtension.setQName(attributeName);
attributeExtension.setValue(attributeValue);
attributeExtension.setAttribute(true);
}
extensible.getAttributeExtensions().add(attributeExtension);
}
}
}
}
/**
*
* @param writer
* @param extensibleElement
* @param extensionAttributeProcessor
* @param context TODO
* @param attributeModel
* @throws ContributionWriteException
* @throws XMLStreamException
*/
protected void writeExtendedAttributes(XMLStreamWriter writer,
Extensible extensibleElement,
StAXAttributeProcessor extensionAttributeProcessor, ProcessorContext context)
throws ContributionWriteException, XMLStreamException {
for (Extension extension : extensibleElement.getAttributeExtensions()) {
if (extension.isAttribute()) {
extensionAttributeProcessor.write(extension, writer, context);
}
}
}
protected void readExtendedElement(XMLStreamReader reader,
Extensible extensible,
StAXArtifactProcessor extensionProcessor, ProcessorContext context)
throws ContributionReadException, XMLStreamException {
Object ext = extensionProcessor.read(reader, context);
if (extensible != null) {
extensible.getExtensions().add(ext);
}
}
protected void writeExtendedElements(XMLStreamWriter writer,
Extensible extensible,
StAXArtifactProcessor extensionProcessor, ProcessorContext context)
throws ContributionWriteException, XMLStreamException {
List <Object> otherExtensions = new ArrayList<Object>();
// write all generic extensions as elements
// to produce semanticaly equal xml output
for (Object ext : extensible.getExtensions()) {
if (ext instanceof Extension) {
extensionProcessor.write(ext, writer, context);
} else {
otherExtensions.add(ext);
}
}
//wrap xml extensibility into a extension wrapper element
if(otherExtensions.size() > 0) {
writeStart(writer, SCA11_NS, "extensions");
for (Object extension : otherExtensions) {
extensionProcessor.write(extension, writer, context);
}
writeEnd(writer);
}
}
/**
* Represents an XML attribute that needs to be written to a document.
*/
public static class XAttr {
private static final String SCA11_NS = "http://docs.oasis-open.org/ns/opencsa/sca/200912";
private String uri = SCA11_NS;
private String name;
private Object value;
public XAttr(String uri, String name, String value) {
this.uri = uri;
this.name = name;
this.value = value;
}
public XAttr(String name, String value) {
this(null, name, value);
}
public XAttr(String uri, String name, List<?> values) {
this.uri = uri;
this.name = name;
this.value = values;
}
public XAttr(String name, List<?> values) {
this(null, name, values);
}
public XAttr(String uri, String name, Boolean value) {
this.uri = uri;
this.name = name;
this.value = value;
}
public XAttr(String name, Boolean value) {
this(null, name, value);
}
public XAttr(String uri, String name, Integer value) {
this.uri = uri;
this.name = name;
this.value = value;
}
public XAttr(String name, Integer value) {
this(null, name, value);
}
public XAttr(String uri, String name, Double value) {
this.uri = uri;
this.name = name;
this.value = value;
}
public XAttr(String name, Double value) {
this(null, name, value);
}
public XAttr(String uri, String name, QName value) {
this.uri = uri;
this.name = name;
this.value = value;
}
public XAttr(String name, QName value) {
this(null, name, value);
}
public String toString() {
return uri == null ? name + "=\"" + value + "\"" : "{" + uri + "}" + name + "=\"" + value + "\"";
}
/**
* Writes a string from a QName and registers a prefix for its namespace.
* @param reader
* @param value
* @return
*/
private String writeQNameValue(XMLStreamWriter writer, QName qname) throws XMLStreamException {
if (qname != null) {
String prefix = helper.writeNamespace(writer, qname.getPrefix(), qname.getNamespaceURI());
if ("".equals(prefix)) {
return qname.getLocalPart();
} else {
return prefix + ":" + qname.getLocalPart();
}
}
return null;
}
/**
* Write to document
* @param writer
* @throws XMLStreamException
*/
public void write(XMLStreamWriter writer) throws XMLStreamException {
String str;
if (value instanceof QName) {
// Write a QName
str = writeQNameValue(writer, (QName)value);
} else if (value instanceof Collection) {
// Write a list of values
Collection<?> values = (Collection<?>)value;
if (values.isEmpty()) {
return;
}
StringBuffer buffer = new StringBuffer();
for (Object v: values) {
if (v == null) {
// Skip null values
continue;
}
if (v instanceof XAttr) {
// Write an XAttr value
((XAttr)v).write(writer);
continue;
}
if (buffer.length() != 0) {
buffer.append(' ');
}
if (v instanceof QName) {
// Write a QName value
buffer.append(writeQNameValue(writer, (QName)v));
} else {
// Write value as a string
buffer.append(String.valueOf(v));
}
}
str = buffer.toString();
} else {
// Write a string
if (value == null) {
return;
}
str = String.valueOf(value);
}
if (str.length() == 0 && (value instanceof Collection)) {
return;
}
helper.writeAttribute(writer, "", name, uri, str);
}
}
}