*/
public final class XmlTreeBuilder {
- private final static XMLInputFactory xmlInputFactory = XMLInputFactory
- .newInstance();
- private static XMLEventReader eventReader;
-
- private XmlTreeBuilder() {
- }
-
- /**
- * The method is designed to take and parse XML as {@link InputStream}. The
- * output of the operation SHOULD be root <code>CompositeNode</code> or
- * <code>SimpleElement</code> depends on element that XML document begins.
- * The XML header is omitted by XML parser.
- *
- * @param inputStream
- * XML Input Stream
- * @return root <code>Node</code> element conformant to XML start element in
- * most cases it will be CompositeNode which contains child Nodes
- * @throws XMLStreamException
- */
- public static Node<?> buildDataTree(final InputStream inputStream)
- throws XMLStreamException {
- eventReader = xmlInputFactory.createXMLEventReader(inputStream);
-
- final Stack<Node<?>> processingQueue = new Stack<>();
- Node<?> parentNode = null;
- Node<?> root = null;
- while (eventReader.hasNext()) {
- final XMLEvent event = eventReader.nextEvent();
-
- if (event.isStartElement()) {
- final StartElement startElement = event.asStartElement();
- if (!processingQueue.isEmpty()) {
- parentNode = processingQueue.peek();
- }
- CompositeNode compParentNode = null;
- if (parentNode instanceof CompositeNode) {
- compParentNode = (CompositeNode) parentNode;
- }
- Node<?> newNode = null;
- if (isCompositeNodeEvent(event)) {
- newNode = resolveCompositeNodeFromStartElement(
- startElement, compParentNode);
- } else if (isSimpleNodeEvent(event)) {
- newNode = resolveSimpleNodeFromStartElement(startElement,
- compParentNode);
- }
-
- if (newNode != null) {
- processingQueue.push(newNode);
- if (compParentNode != null) {
- compParentNode.getChildren().add(newNode);
- }
- }
- } else if (event.isEndElement()) {
- root = processingQueue.pop();
- }
- }
- return root;
- }
-
- /**
- * Checks if the XMLEvent is compliant to SimpleNode tag that contains only
- * characters value. If the SimpleNode is composed only by empty XML tag
- * (i.e. {@code <emptyTag />} or {@code<emptyTag></emptyTag>}) the result
- * will be also <code>true</code>.
- *
- * @param event
- * actual XMLEvent that is processed
- * @return <code>true</code> only and only if the XMLEvent Start Element is
- * Simple element tag and contains character values or is empty XML
- * tag.
- *
- * @see SimpleNode
- */
- private static boolean isSimpleNodeEvent(final XMLEvent event) {
- checkArgument(event != null, "XML Event cannot be NULL!");
- if (event.isStartElement()) {
- if (eventReader.hasNext()) {
- final XMLEvent innerEvent;
- try {
- innerEvent = eventReader.peek();
- if (innerEvent.isCharacters()) {
- final Characters chars = innerEvent.asCharacters();
- if (!chars.isWhiteSpace()) {
- return true;
- }
- } else if (innerEvent.isEndElement()) {
- return true;
- }
- } catch (XMLStreamException e) {
- e.printStackTrace();
- }
- }
- }
- return false;
- }
-
- /**
- * Checks if XMLEvent is equivalent to CompositeNode Event. The
- * CompositeNode Event is XML element that conforms to the XML element that
- * contains 1..N XML child elements. (i.e. {@code <compositeNode>
- * <simpleNode>data</simpleNode>
- * </compositeNode>})
- *
- * @param event
- * actual XMLEvent that is processed
- * @return <code>true</code> only if XML Element contains 1..N child
- * elements, otherwise returns <code>false</code>
- *
- * @see CompositeNode
- */
- private static boolean isCompositeNodeEvent(final XMLEvent event) {
- checkArgument(event != null, "XML Event cannot be NULL!");
- if (event.isStartElement()) {
- if (eventReader.hasNext()) {
- XMLEvent innerEvent;
- try {
- innerEvent = eventReader.peek();
- if (innerEvent.isCharacters()) {
- Characters chars = innerEvent.asCharacters();
- if (chars.isWhiteSpace()) {
- eventReader.nextEvent();
- innerEvent = eventReader.peek();
- }
- }
- if (innerEvent.isStartElement()) {
- return true;
- }
- } catch (XMLStreamException e) {
- e.printStackTrace();
- }
- }
- }
- return false;
- }
-
- /**
- * Creates and returns <code>SimpleNode</code> instance from actually
- * processed XML Start Element.
- *
- * @param startElement
- * actual XML Start Element that is processed
- * @param parent
- * Parent CompositeNode
- * @return <code>new SimpleNode</code> instance from actually processed XML
- * Start Element
- * @throws XMLStreamException
- *
- * @see SimpleNode
- */
- private static SimpleNode<String> resolveSimpleNodeFromStartElement(
- final StartElement startElement, CompositeNode parent)
- throws XMLStreamException {
- checkArgument(startElement != null, "Start Element cannot be NULL!");
- String data = null;
-
- if (eventReader.hasNext()) {
- final XMLEvent innerEvent = eventReader.peek();
- if (innerEvent.isCharacters()) {
- final Characters chars = innerEvent.asCharacters();
- if (!chars.isWhiteSpace()) {
- data = innerEvent.asCharacters().getData();
- }
- } else if (innerEvent.isEndElement()) {
- data = "";
- }
- }
- return NodeFactory.createImmutableSimpleNode(
- resolveElementQName(startElement), parent, data);
- }
-
- /**
- * Creates and returns <code>MutableCompositeNode</code> instance from
- * actually processed XML Start Element.
- *
- * @param startElement
- * actual XML Start Element that is processed
- * @param parent
- * Parent CompositeNode
- * @return <code>new MutableCompositeNode</code> instance from actually
- * processed XML Start Element
- *
- * @see CompositeNode
- * @see MutableCompositeNode
- */
- private static CompositeNode resolveCompositeNodeFromStartElement(
- final StartElement startElement, CompositeNode parent) {
- checkArgument(startElement != null, "Start Element cannot be NULL!");
-
- return NodeFactory.createMutableCompositeNode(
- resolveElementQName(startElement), parent,
- new ArrayList<Node<?>>(), ModifyAction.CREATE, null);
- }
-
- /**
- * Extract and retrieve XML Element QName to OpenDaylight QName.
- *
- * @param element
- * Start Element
- * @return QName instance composed of <code>elements</code> Namespace and
- * Local Part.
- *
- * @see QName
- */
- private static QName resolveElementQName(final StartElement element) {
- checkArgument(element != null, "Start Element cannot be NULL!");
-
- final String nsURI = element.getName().getNamespaceURI();
- final String localName = element.getName().getLocalPart();
- return new QName(URI.create(nsURI), localName);
- }
+ private final static XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+ private static XMLEventReader eventReader;
+
+ private XmlTreeBuilder() {
+ }
+
+ /**
+ * The method is designed to take and parse XML as {@link InputStream}. The
+ * output of the operation SHOULD be root <code>CompositeNode</code> or
+ * <code>SimpleElement</code> depends on element that XML document begins.
+ * The XML header is omitted by XML parser.
+ *
+ * @param inputStream
+ * XML Input Stream
+ * @return root <code>Node</code> element conformant to XML start element in
+ * most cases it will be CompositeNode which contains child Nodes
+ * @throws XMLStreamException
+ */
+ public static Node<?> buildDataTree(final InputStream inputStream) throws XMLStreamException {
+ eventReader = xmlInputFactory.createXMLEventReader(inputStream);
+
+ final Stack<Node<?>> processingQueue = new Stack<>();
+ Node<?> parentNode = null;
+ Node<?> root = null;
+ while (eventReader.hasNext()) {
+ final XMLEvent event = eventReader.nextEvent();
+
+ if (event.isStartElement()) {
+ final StartElement startElement = event.asStartElement();
+ if (!processingQueue.isEmpty()) {
+ parentNode = processingQueue.peek();
+ }
+ CompositeNode compParentNode = null;
+ if (parentNode instanceof CompositeNode) {
+ compParentNode = (CompositeNode) parentNode;
+ }
+ Node<?> newNode = null;
+ if (isCompositeNodeEvent(event)) {
+ newNode = resolveCompositeNodeFromStartElement(startElement, compParentNode);
+ } else if (isSimpleNodeEvent(event)) {
+ newNode = resolveSimpleNodeFromStartElement(startElement, compParentNode);
+ }
+
+ if (newNode != null) {
+ processingQueue.push(newNode);
+ if (compParentNode != null) {
+ compParentNode.getChildren().add(newNode);
+ }
+ }
+ } else if (event.isEndElement()) {
+ root = processingQueue.pop();
+ }
+ }
+ return root;
+ }
+
+ /**
+ * Checks if the XMLEvent is compliant to SimpleNode tag that contains only
+ * characters value. If the SimpleNode is composed only by empty XML tag
+ * (i.e. {@code <emptyTag />} or {@code<emptyTag></emptyTag>}) the result
+ * will be also <code>true</code>.
+ *
+ * @param event
+ * actual XMLEvent that is processed
+ * @return <code>true</code> only and only if the XMLEvent Start Element is
+ * Simple element tag and contains character values or is empty XML
+ * tag.
+ * @throws XMLStreamException
+ *
+ * @see SimpleNode
+ */
+ private static boolean isSimpleNodeEvent(final XMLEvent event) throws XMLStreamException {
+ checkArgument(event != null, "XML Event cannot be NULL!");
+ if (event.isStartElement()) {
+ if (eventReader.hasNext()) {
+ final XMLEvent innerEvent;
+ innerEvent = eventReader.peek();
+ if (innerEvent.isCharacters()) {
+ final Characters chars = innerEvent.asCharacters();
+ if (!chars.isWhiteSpace()) {
+ return true;
+ }
+ } else if (innerEvent.isEndElement()) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Checks if XMLEvent is equivalent to CompositeNode Event. The
+ * CompositeNode Event is XML element that conforms to the XML element that
+ * contains 1..N XML child elements. (i.e. {@code <compositeNode>
+ * <simpleNode>data</simpleNode>
+ * </compositeNode>})
+ *
+ * @param event
+ * actual XMLEvent that is processed
+ * @return <code>true</code> only if XML Element contains 1..N child
+ * elements, otherwise returns <code>false</code>
+ * @throws XMLStreamException
+ *
+ * @see CompositeNode
+ */
+ private static boolean isCompositeNodeEvent(final XMLEvent event) throws XMLStreamException {
+ checkArgument(event != null, "XML Event cannot be NULL!");
+ if (event.isStartElement()) {
+ if (eventReader.hasNext()) {
+ XMLEvent innerEvent;
+ innerEvent = eventReader.peek();
+ if (innerEvent.isCharacters()) {
+ Characters chars = innerEvent.asCharacters();
+ if (chars.isWhiteSpace()) {
+ eventReader.nextEvent();
+ innerEvent = eventReader.peek();
+ }
+ }
+ if (innerEvent.isStartElement()) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Creates and returns <code>SimpleNode</code> instance from actually
+ * processed XML Start Element.
+ *
+ * @param startElement
+ * actual XML Start Element that is processed
+ * @param parent
+ * Parent CompositeNode
+ * @return <code>new SimpleNode</code> instance from actually processed XML
+ * Start Element
+ * @throws XMLStreamException
+ *
+ * @see SimpleNode
+ */
+ private static SimpleNode<String> resolveSimpleNodeFromStartElement(final StartElement startElement,
+ CompositeNode parent) throws XMLStreamException {
+ checkArgument(startElement != null, "Start Element cannot be NULL!");
+ String data = null;
+
+ if (eventReader.hasNext()) {
+ final XMLEvent innerEvent = eventReader.peek();
+ if (innerEvent.isCharacters()) {
+ final Characters chars = innerEvent.asCharacters();
+ if (!chars.isWhiteSpace()) {
+ data = innerEvent.asCharacters().getData();
+ }
+ } else if (innerEvent.isEndElement()) {
+ data = "";
+ }
+ }
+ return NodeFactory.createImmutableSimpleNode(resolveElementQName(startElement), parent, data);
+ }
+
+ /**
+ * Creates and returns <code>MutableCompositeNode</code> instance from
+ * actually processed XML Start Element.
+ *
+ * @param startElement
+ * actual XML Start Element that is processed
+ * @param parent
+ * Parent CompositeNode
+ * @return <code>new MutableCompositeNode</code> instance from actually
+ * processed XML Start Element
+ *
+ * @see CompositeNode
+ * @see MutableCompositeNode
+ */
+ private static CompositeNode resolveCompositeNodeFromStartElement(final StartElement startElement,
+ CompositeNode parent) {
+ checkArgument(startElement != null, "Start Element cannot be NULL!");
+
+ return NodeFactory.createMutableCompositeNode(resolveElementQName(startElement), parent,
+ new ArrayList<Node<?>>(), ModifyAction.CREATE, null);
+ }
+
+ /**
+ * Extract and retrieve XML Element QName to OpenDaylight QName.
+ *
+ * @param element
+ * Start Element
+ * @return QName instance composed of <code>elements</code> Namespace and
+ * Local Part.
+ *
+ * @see QName
+ */
+ private static QName resolveElementQName(final StartElement element) {
+ checkArgument(element != null, "Start Element cannot be NULL!");
+
+ final String nsURI = element.getName().getNamespaceURI();
+ final String localName = element.getName().getLocalPart();
+ return new QName(URI.create(nsURI), localName);
+ }
}
Code Review / yangtools.git / commitdiff