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eXist-db NoSQL Database Core
/*
* eXist-db Open Source Native XML Database
* Copyright (C) 2001 The eXist-db Authors
*
* [email protected]
* http://www.exist-db.org
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.validation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ServiceLoader;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.util.ExistSAXParserFactory;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
/**
* Class for checking dependencies with XML libraries.
*
* @author Adam Retter
*/
public class XmlLibraryChecker {
/**
* Possible XML Parsers, at least one must be valid
*/
private final static ClassVersion[] validParsers = {
new ClassVersion("Xerces", "Xerces-J 2.10.0", "org.apache.xerces.impl.Version.getVersion()")
};
/**
* Possible XML Transformers, at least one must be valid
*/
private final static ClassVersion[] validTransformers = {
new ClassVersion("Saxon", "8.9.0", "net.sf.saxon.Version.getProductVersion()"),
new ClassVersion("Xalan", "Xalan Java 2.7.1", "org.apache.xalan.Version.getVersion()"),
};
/**
* Possible XML resolvers, at least one must be valid
*/
private final static ClassVersion[] validResolvers = {
new ClassVersion("Resolver", "XmlResolver 1.2", "org.apache.xml.resolver.Version.getVersion()"),
};
private final static Logger logger = LogManager.getLogger( XmlLibraryChecker.class );
/**
* Remove "@" from string.
*/
private static String getClassName(String classid) {
String className;
final int lastChar = classid.lastIndexOf('@');
if (lastChar == -1) {
className = classid;
} else {
className = classid.substring(0, lastChar);
}
return className;
}
/**
* Determine the class that is actually used as XML parser.
*
* @return Full classname of parser.
*/
private static String determineActualParserClass() {
String parserClass = "Unable to determine parser class";
try {
final SAXParserFactory factory = ExistSAXParserFactory.getSAXParserFactory();
final XMLReader xmlReader = factory.newSAXParser().getXMLReader();
final String classId = xmlReader.toString();
parserClass = getClassName(classId);
} catch (final ParserConfigurationException | SAXException ex) {
logger.error(ex.getMessage());
}
return parserClass;
}
/**
* Determine the class that is actually used as XML transformer.
*
* @return Full classname of transformer.
*/
private static String determineActualTransformerClass(){
String transformerClass = "Unable to determine transformer class";
try {
final TransformerFactory factory = TransformerFactory.newInstance();
final Transformer transformer = factory.newTransformer();
final String classId = transformer.toString();
transformerClass = getClassName(classId);
} catch (final TransformerConfigurationException ex) {
logger.error(ex.getMessage());
}
return transformerClass;
}
/**
* Perform checks on parsers, transformers and resolvers.
*/
public static void check() {
StringBuilder message = new StringBuilder();
/*
* Parser
*/
final ServiceLoader allSax = ServiceLoader.load(SAXParserFactory.class);
for(final SAXParserFactory sax : allSax){
message.append(getClassName(sax.toString()));
message.append(" ");
}
logger.debug("Detected SAXParserFactory classes: {}", message.toString());
message = new StringBuilder();
boolean invalidVersionFound = false;
if( hasValidClassVersion( "Parser", validParsers, message ) ) {
logger.info( message.toString() );
} else {
logger.warn(message.toString());
invalidVersionFound = true;
}
/*
* Transformer
*/
message = new StringBuilder();
final ServiceLoader allXsl = ServiceLoader.load(TransformerFactory.class);
for(final TransformerFactory xsl : allXsl){
message.append(getClassName(xsl.toString()));
message.append(" ");
}
logger.debug("Detected TransformerFactory classes: {}", message.toString());
message = new StringBuilder();
if( hasValidClassVersion( "Transformer", validTransformers, message ) ) {
logger.info( message.toString() );
} else {
logger.warn( message.toString() );
System.err.println( message.toString() );
invalidVersionFound = true;
}
/*
* Resolver
*/
message = new StringBuilder();
if( hasValidClassVersion( "Resolver", validResolvers, message ) ) {
logger.info(message.toString());
} else {
logger.warn(message.toString());
invalidVersionFound = true;
}
logger.info("Using parser {}", determineActualParserClass());
logger.info("Using transformer {}", determineActualTransformerClass());
if(invalidVersionFound) {
logger.warn("Using parser {}", determineActualParserClass());
logger.warn("Using transformer {}", determineActualTransformerClass());
}
}
/**
* Check if for the specified service object one of the required
* classes is available.
*
* @param type Parser, Transformer or Resolver, used for reporting only.
* @param validClasses Array of valid classes.
* @param message Output message of detecting classes.
* @return TRUE if valid class has been found, otherwise FALSE.
*/
public static boolean hasValidClassVersion(String type,
ClassVersion[] validClasses, StringBuilder message) {
final String sep = System.getProperty("line.separator");
message.append("Looking for a valid ").append(type).append("...").append(sep);
for (final ClassVersion validClass : validClasses) {
final String actualVersion = validClass.getActualVersion();
message.append("Checking for ").append(validClass.getSimpleName());
if (actualVersion != null) {
message.append(", found version ").append(actualVersion);
if (actualVersion.compareToIgnoreCase(
validClass.getRequiredVersion()) >= 0) {
message.append(sep).append("OK!").append(sep);
return true;
} else {
message.append(" needed version ").append(validClass.getRequiredVersion()).append(sep);
}
} else {
message.append(", not found!").append(sep);
}
}
message.append("Warning: Failed find a valid ").append(type).append("!").append(sep);
message.append(sep).append("Please add an appropriate ").append(type)
.append(" to the " + "class-path, e.g. in the 'endorsed' folder of "
+ "the servlet container or in the 'endorsed' folder of the JRE.")
.append(sep);
return false;
}
/**
* Checks to see if a valid XML Parser exists
*
* @return boolean true indicates a valid Parser was found, false otherwise
*/
public static boolean hasValidParser() {
return hasValidParser(new StringBuilder());
}
/**
* Checks to see if a valid XML Parser exists
*
* @param message Messages about the status of available Parser's will
* be appended to this buffer
*
* @return boolean true indicates a valid Parser was found, false otherwise
*/
public static boolean hasValidParser(StringBuilder message) {
return hasValidClassVersion("Parser", validParsers, message);
}
/**
* Checks to see if a valid XML Transformer exists
*
* @return boolean true indicates a valid Transformer was found,
* false otherwise
*/
public static boolean hasValidTransformer() {
return hasValidTransformer(new StringBuilder());
}
/**
* Checks to see if a valid XML Transformer exists
*
* @param message Messages about the status of available Transformer's
* will be appended to this buffer
*
* @return boolean true indicates a valid Transformer was found,
* false otherwise
*/
public static boolean hasValidTransformer(StringBuilder message) {
return hasValidClassVersion("Transformer", validTransformers, message);
}
/**
* Simple class to describe a class, its required version and how to
* obtain the actual version
*/
public static class ClassVersion {
private final String simpleName;
private final String requiredVersion;
private final String versionFunction;
/**
* Default Constructor
*
* @param simpleName The simple name for the class (just a
* descriptor really)
* @param requiredVersion The required version of the class
* @param versionFunction The function to be invoked to obtain the
* actual version of the class, must be fully
* qualified (i.e. includes the package name)
*/
ClassVersion(String simpleName, String requiredVersion, String versionFunction) {
this.simpleName = simpleName;
this.requiredVersion = requiredVersion;
this.versionFunction = versionFunction;
}
/**
* @return the simple name of the class
*/
public String getSimpleName() {
return simpleName;
}
/**
* @return the required version of the class
*/
public String getRequiredVersion() {
return requiredVersion;
}
/**
* Invokes the specified versionFunction using reflection to get the
* actual version of the class
*
* @return the actual version of the class
*/
public String getActualVersion() {
String actualVersion = null;
//get the class name from the specifiec version function string
final String versionClassName = versionFunction
.substring(0, versionFunction.lastIndexOf('.'));
//get the function name from the specifiec version function string
final String versionFunctionName = versionFunction.substring(
versionFunction.lastIndexOf('.') + 1, versionFunction.lastIndexOf('('));
try {
//get the class
final Class versionClass = Class.forName(versionClassName);
//get the method
final Method getVersionMethod = versionClass.getMethod(versionFunctionName, (Class[]) null);
//invoke the method on the class
actualVersion = (String) getVersionMethod.invoke(versionClass, (Object[]) null);
} catch (final ClassNotFoundException | NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
logger.debug(ex.getMessage());
}
//return the actual version
return actualVersion;
}
}
}
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