/*
* #%L
* =====================================================
* _____ _ ____ _ _ _ _
* |_ _|_ __ _ _ ___| |_ / __ \| | | | ___ | | | |
* | | | '__| | | / __| __|/ / _` | |_| |/ __|| |_| |
* | | | | | |_| \__ \ |_| | (_| | _ |\__ \| _ |
* |_| |_| \__,_|___/\__|\ \__,_|_| |_||___/|_| |_|
* \____/
*
* =====================================================
*
* Hochschule Hannover
* (University of Applied Sciences and Arts, Hannover)
* Faculty IV, Dept. of Computer Science
* Ricklinger Stadtweg 118, 30459 Hannover, Germany
*
* Email: trust@f4-i.fh-hannover.de
* Website: http://trust.f4.hs-hannover.de/
*
* This file is part of visitmeta-common, version 0.6.0,
* implemented by the Trust@HsH research group at the Hochschule Hannover.
* %%
* Copyright (C) 2012 - 2016 Trust@HsH
* %%
* Licensed 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.
* #L%
*/
package de.hshannover.f4.trust.visitmeta.util;
import java.io.IOException;
import java.io.StringReader;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Utility class for W3C {@link Document} objects.
*
* @author Bastian Hellmann
*
*/
public class DocumentUtils {
/**
* Private constructor, as the the class only contains static methods.
*/
private DocumentUtils() {
}
private static final Logger LOGGER = Logger.getLogger(DocumentUtils.class);
private static final String[] NAME_TYPE_VALUE_ARRAY = new String[] {
"name", "value", "type"};
public static final Set<String> NAME_TYPE_VALUE = new HashSet<>(
Arrays.asList(NAME_TYPE_VALUE_ARRAY));
private static DocumentBuilderFactory mFactory;
private static DocumentBuilder mBuilder;
static {
mFactory = DocumentBuilderFactory.newInstance();
try {
mBuilder = mFactory.newDocumentBuilder();
} catch (ParserConfigurationException e) {
LOGGER.error(e.getMessage());
}
}
/**
* Takes escaped XML as a {@link String} and replaces any escaped character
* with its non-escaped version.
*
* <ul>
* <li>& -> &
* <li>< -> <
* <li>> -> >
* <li>" -> "
* <li>' -> '
* </ul>
*
* @param input
* @return
*/
public static String deEscapeXml(String input) {
String ret = input;
String[] unwanted = {"&", "<", ">", """, "'"};
String[] replaceBy = {"&", "<", ">", "\"", "'"};
for (int i = 0; i < unwanted.length; i++) {
ret = ret.replace(unwanted[i], replaceBy[i]);
}
return ret;
}
/**
* Parses a {@link String} containing a XML document to a {@link Document}.
*
* @param input
* XML document as one {@link String}
* @return a {@link Document}
*/
public static synchronized Document parseXmlString(String input) {
Document document = null;
try {
document = mBuilder.parse(new InputSource(new StringReader(input)));
} catch (SAXException | IOException e) {
LOGGER.error(e.getMessage());
}
return document;
}
/**
* Convenience method; takes an escaped XML document as input and returns a
* {@link Document} object.
*
* @param input
* escaped XML as one {@link String}
* @return a {@link Document}
*/
public static Document parseEscapedXmlString(String input) {
String deEscapedXml = deEscapeXml(input);
return parseXmlString(deEscapedXml);
}
private static String extractSingleInformation(Document document, String key) {
Element documentElement = document.getDocumentElement();
NodeList childNodes = document.getChildNodes();
String result = null;
for (int i = 0; i < childNodes.getLength(); i++) {
Node item = childNodes.item(i);
if (item.getNodeName().equals(key)) {
result = item.getNodeValue();
}
}
if (result == null
|| result.equals("")) {
result = documentElement.getAttribute(key);
}
return result;
}
/**
* Tries to extract information of a given {@link Document} object, by
* looking for child elements and attributes at the root-node of the
* document.
*
* @param document
* a {@link Document} object
* @param keys
* a {@link Set} of keys that are looked up in the
* {@link Document}
* @return a {@link Map} containing all keys and their found values
*/
public static Map<String, String> extractInformation(Document document,
Set<String> keys) {
HashMap<String, String> result = new HashMap<>();
String tmpValue;
for (String key : keys) {
tmpValue = extractSingleInformation(document, key);
if (tmpValue != null
&& !tmpValue.isEmpty()) {
result.put(key, tmpValue);
}
}
return result;
}
}