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The Core Camel Java DSL based router
/**
* 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.camel.util;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.util.Stack;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* An XML parser that uses SAX to include line and column number for each XML element in the parsed Document.
*
* The line number and column number can be obtained from a Node/Element using
*
* String lineNumber = (String) node.getUserData(XmlLineNumberParser.LINE_NUMBER);
* String lineNumberEnd = (String) node.getUserData(XmlLineNumberParser.LINE_NUMBER_END);
* String columnNumber = (String) node.getUserData(XmlLineNumberParser.COLUMN_NUMBER);
* String columnNumberEnd = (String) node.getUserData(XmlLineNumberParser.COLUMN_NUMBER_END);
*
*/
public final class XmlLineNumberParser {
public static final String LINE_NUMBER = "lineNumber";
public static final String COLUMN_NUMBER = "colNumber";
public static final String LINE_NUMBER_END = "lineNumberEnd";
public static final String COLUMN_NUMBER_END = "colNumberEnd";
/**
* Allows to plugin a custom text transformer in the parser, that can transform all the text content
*/
public interface XmlTextTransformer {
String transform(String text);
}
private XmlLineNumberParser() {
}
/**
* Parses the XML.
*
* @param is the XML content as an input stream
* @return the DOM model
* @throws Exception is thrown if error parsing
*/
public static Document parseXml(final InputStream is) throws Exception {
return parseXml(is, null);
}
/**
* Parses the XML.
*
* @param is the XML content as an input stream
* @param xmlTransformer the XML transformer
* @return the DOM model
* @throws Exception is thrown if error parsing
*/
public static Document parseXml(final InputStream is, final XmlTextTransformer xmlTransformer) throws Exception {
return parseXml(is, xmlTransformer, null, null);
}
/**
* Parses the XML.
*
* @param is the XML content as an input stream
* @param xmlTransformer the XML transformer
* @param rootNames one or more root names that is used as baseline for beginning the parsing, for example camelContext to start parsing
* when Camel is discovered. Multiple names can be defined separated by comma
* @param forceNamespace an optional namespaces to force assign to each node. This may be needed for JAXB unmarshalling from XML -> POJO.
* @return the DOM model
* @throws Exception is thrown if error parsing
*/
public static Document parseXml(final InputStream is, XmlTextTransformer xmlTransformer, String rootNames, final String forceNamespace) throws Exception {
ObjectHelper.notNull(is, "is");
final XmlTextTransformer transformer = xmlTransformer == null ? new NoopTransformer() : xmlTransformer;
final Document doc;
SAXParser parser;
final SAXParserFactory factory = SAXParserFactory.newInstance();
parser = factory.newSAXParser();
final DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
// turn off validator and loading external dtd
dbf.setValidating(false);
dbf.setNamespaceAware(true);
dbf.setFeature("http://xml.org/sax/features/namespaces", false);
dbf.setFeature("http://xml.org/sax/features/validation", false);
dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", false);
dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
dbf.setFeature("http://xml.org/sax/features/external-general-entities", false);
final DocumentBuilder docBuilder = dbf.newDocumentBuilder();
doc = docBuilder.newDocument();
final Stack elementStack = new Stack();
final StringBuilder textBuffer = new StringBuilder();
final DefaultHandler handler = new DefaultHandler() {
private Locator locator;
private boolean found;
@Override
public void setDocumentLocator(final Locator locator) {
this.locator = locator; // Save the locator, so that it can be used later for line tracking when traversing nodes.
this.found = rootNames == null;
}
private boolean isRootName(String qName) {
for (String root : rootNames.split(",")) {
if (qName.equals(root)) {
return true;
}
}
return false;
}
@Override
public void startElement(final String uri, final String localName, final String qName, final Attributes attributes) throws SAXException {
addTextIfNeeded();
if (rootNames != null && !found) {
if (isRootName(qName)) {
found = true;
}
}
if (found) {
Element el;
if (forceNamespace != null) {
el = doc.createElementNS(forceNamespace, qName);
} else {
el = doc.createElement(qName);
}
for (int i = 0; i < attributes.getLength(); i++) {
el.setAttribute(transformer.transform(attributes.getQName(i)), transformer.transform(attributes.getValue(i)));
}
el.setUserData(LINE_NUMBER, String.valueOf(this.locator.getLineNumber()), null);
el.setUserData(COLUMN_NUMBER, String.valueOf(this.locator.getColumnNumber()), null);
elementStack.push(el);
}
}
@Override
public void endElement(final String uri, final String localName, final String qName) {
if (!found) {
return;
}
addTextIfNeeded();
final Element closedEl = elementStack.isEmpty() ? null : elementStack.pop();
if (closedEl != null) {
if (elementStack.isEmpty()) {
// Is this the root element?
doc.appendChild(closedEl);
} else {
final Element parentEl = elementStack.peek();
parentEl.appendChild(closedEl);
}
closedEl.setUserData(LINE_NUMBER_END, String.valueOf(this.locator.getLineNumber()), null);
closedEl.setUserData(COLUMN_NUMBER_END, String.valueOf(this.locator.getColumnNumber()), null);
}
}
@Override
public void characters(final char ch[], final int start, final int length) throws SAXException {
char[] chars = new char[length];
System.arraycopy(ch, start, chars, 0, length);
String s = new String(chars);
s = transformer.transform(s);
textBuffer.append(s);
}
@Override
public InputSource resolveEntity(String publicId, String systemId) throws IOException, SAXException {
// do not resolve external dtd
return new InputSource(new StringReader(""));
}
// Outputs text accumulated under the current node
private void addTextIfNeeded() {
if (textBuffer.length() > 0) {
final Element el = elementStack.isEmpty() ? null : elementStack.peek();
if (el != null) {
final Node textNode = doc.createTextNode(textBuffer.toString());
el.appendChild(textNode);
textBuffer.delete(0, textBuffer.length());
}
}
}
};
parser.parse(is, handler);
return doc;
}
private static final class NoopTransformer implements XmlTextTransformer {
@Override
public String transform(String text) {
return text;
}
}
}