com.gccloud.starter.common.utils.XmlUtils Maven / Gradle / Ivy
package com.gccloud.starter.common.utils;
/*
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig 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 the following location:
*
* 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.
*/
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Common utilities for easily parsing XML without duplicating logic.
*
* @author Scott Battaglia
* @version $Revision: 11729 $ $Date: 2007-09-26 14:22:30 -0400 (Tue, 26 Sep 2007) $
* @since 3.0
*/
public final class XmlUtils {
/**
* Static instance of Commons Logging.
*/
private final static Logger LOGGER = LoggerFactory.getLogger(XmlUtils.class);
/**
* Creates a new namespace-aware DOM document object by parsing the given XML.
*
* @param xml XML content.
* @return DOM document.
*/
public static Document newDocument(final String xml) {
final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
final Map features = new HashMap();
features.put(XMLConstants.FEATURE_SECURE_PROCESSING, true);
features.put("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
for (final Map.Entry entry : features.entrySet()) {
try {
factory.setFeature(entry.getKey(), entry.getValue());
} catch (ParserConfigurationException e) {
LOGGER.warn("Failed setting XML feature {}: {}", entry.getKey(), e);
}
}
factory.setNamespaceAware(true);
try {
return factory.newDocumentBuilder().parse(new InputSource(new StringReader(xml)));
} catch (Exception e) {
throw new RuntimeException("XML parsing error: " + e);
}
}
/**
* Get an instance of an XML reader from the XMLReaderFactory.
*
* @return the XMLReader.
*/
public static XMLReader getXmlReader() {
try {
final XMLReader reader = SAXParserFactory.newInstance().newSAXParser().getXMLReader();
reader.setFeature("http://xml.org/sax/features/namespaces", true);
reader.setFeature("http://xml.org/sax/features/namespace-prefixes", false);
reader.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
return reader;
} catch (final Exception e) {
throw new RuntimeException("Unable to create XMLReader", e);
}
}
/**
* Retrieve the text for a group of elements. Each text element is an entry
* in a list.
* This method is currently optimized for the use case of two elements in a list.
*
* @param xmlAsString the xml response
* @param element the element to look for
* @return the list of text from the elements.
*/
public static List getTextForElements(final String xmlAsString, final String element) {
final List elements = new ArrayList(2);
final XMLReader reader = getXmlReader();
final DefaultHandler handler = new DefaultHandler() {
private boolean foundElement = false;
private StringBuilder buffer = new StringBuilder();
public void startElement(final String uri, final String localName, final String qName,
final Attributes attributes) throws SAXException {
if (localName.equals(element)) {
this.foundElement = true;
}
}
public void endElement(final String uri, final String localName, final String qName) throws SAXException {
if (localName.equals(element)) {
this.foundElement = false;
elements.add(this.buffer.toString());
this.buffer = new StringBuilder();
}
}
public void characters(char[] ch, int start, int length) throws SAXException {
if (this.foundElement) {
this.buffer.append(ch, start, length);
}
}
};
reader.setContentHandler(handler);
reader.setErrorHandler(handler);
try {
reader.parse(new InputSource(new StringReader(xmlAsString)));
} catch (final Exception e) {
LOGGER.error(e.getMessage(), e);
return null;
}
return elements;
}
/**
* Retrieve the text for a specific element (when we know there is only
* one).
*
* @param xmlAsString the xml response
* @param element the element to look for
* @return the text value of the element.
*/
public static String getTextForElement(final String xmlAsString, final String element) {
final XMLReader reader = getXmlReader();
final StringBuilder builder = new StringBuilder();
final DefaultHandler handler = new DefaultHandler() {
private boolean foundElement = false;
public void startElement(final String uri, final String localName, final String qName,
final Attributes attributes) throws SAXException {
if (localName.equals(element)) {
this.foundElement = true;
}
}
public void endElement(final String uri, final String localName, final String qName) throws SAXException {
if (localName.equals(element)) {
this.foundElement = false;
}
}
public void characters(char[] ch, int start, int length) throws SAXException {
if (this.foundElement) {
builder.append(ch, start, length);
}
}
};
reader.setContentHandler(handler);
reader.setErrorHandler(handler);
try {
reader.parse(new InputSource(new StringReader(xmlAsString)));
} catch (final Exception e) {
LOGGER.error(e.getMessage(), e);
return null;
}
return builder.toString();
}
}