org.jgroups.conf.ClassConfigurator Maven / Gradle / Ivy
package org.jgroups.conf;
import org.jgroups.Global;
import org.jgroups.util.Triple;
import org.jgroups.util.Util;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.*;
/**
* This class will be replaced with the class that read info
* from the magic number configurator that reads info from the xml file.
* The name and the relative path of the magic number map file can be specified
* as value of the property org.jgroups.conf.magicNumberFile.
* It must be relative to one of the classpath elements, to allow the
* classloader to locate the file. If a value is not specified,
* MagicNumberReader.MAGIC_NUMBER_FILE is used, which defaults
* to "jg-magic-map.xml".
*
* @author Filip Hanik
* @author Bela Ban
*/
public class ClassConfigurator {
public static final String MAGIC_NUMBER_FILE = "jg-magic-map.xml";
public static final String PROTOCOL_ID_FILE = "jg-protocol-ids.xml";
private static final int MAX_MAGIC_VALUE=150;
private static final short MIN_CUSTOM_MAGIC_NUMBER=1024;
private static final short MIN_CUSTOM_PROTOCOL_ID=512;
// this is where we store magic numbers; contains data from jg-magic-map.xml; key=Class, value=magic number
private static final Map classMap=new IdentityHashMap<>(MAX_MAGIC_VALUE);
// Magic map for all values defined in jg-magic-map.xml
private static final Class[] magicMap=new Class[MAX_MAGIC_VALUE]; /// simple array, IDs are the indices
// Magic map for user-defined IDs / classes
private static final Map magicMapUser=new HashMap<>(); // key=magic number, value=Class
/** Contains data read from jg-protocol-ids.xml */
private static final Map protocol_ids=new HashMap<>(MAX_MAGIC_VALUE);
private static final Map protocol_names=new HashMap<>(MAX_MAGIC_VALUE);
static {
try {
init();
}
catch(Exception e) {
throw new ExceptionInInitializerError(e);
}
}
public ClassConfigurator() {
}
protected static void init() throws Exception {
// make sure we have a class for DocumentBuilderFactory
Util.loadClass("javax.xml.parsers.DocumentBuilderFactory", ClassConfigurator.class);
String magic_number_file=null, protocol_id_file=null;
try { // PropertyPermission not granted if running in an untrusted environment with JNLP
magic_number_file=Util.getProperty(new String[]{Global.MAGIC_NUMBER_FILE, "org.jgroups.conf.magicNumberFile"},
null, null, MAGIC_NUMBER_FILE);
protocol_id_file=Util.getProperty(new String[]{Global.PROTOCOL_ID_FILE, "org.jgroups.conf.protocolIDFile"},
null, null, PROTOCOL_ID_FILE);
}
catch (SecurityException ex){
}
// Read jg-magic-map.xml
List> mapping=readMappings(magic_number_file);
for(Triple tuple: mapping) {
short m=tuple.getVal1();
if(m >= MAX_MAGIC_VALUE)
throw new IllegalArgumentException("ID " + m + " is bigger than MAX_MAGIC_VALUE (" +
MAX_MAGIC_VALUE + "); increase MAX_MAGIC_VALUE");
boolean external=tuple.getVal3();
if(external) {
if(magicMap[m] != null)
throw new Exception("ID " + m + " (" + tuple.getVal2() + ')' +
" is already in magic map; make sure that all keys are unique");
continue;
}
Class clazz=Util.loadClass(tuple.getVal2(), ClassConfigurator.class);
if(magicMap[m] != null)
throw new Exception("key " + m + " (" + clazz.getName() + ')' +
" is already in magic map; please make sure that all keys are unique");
magicMap[m]=clazz;
classMap.put(clazz, m);
}
mapping=readMappings(protocol_id_file); // Read jg-protocol-ids.xml
for(Triple tuple: mapping) {
short m=tuple.getVal1();
boolean external=tuple.getVal3();
if(external) {
if(protocol_names.containsKey(m))
throw new Exception("ID " + m + " (" + tuple.getVal2() + ')' +
" is already in protocol-ids map; make sure that all protocol IDs are unique");
continue;
}
Class clazz=Util.loadClass(tuple.getVal2(), ClassConfigurator.class);
if(protocol_ids.containsKey(clazz))
throw new Exception("ID " + m + " (" + clazz.getName() + ')' +
" is already in protocol-ids map; make sure that all protocol IDs are unique");
protocol_ids.put(clazz, m);
protocol_names.put(m, clazz);
}
}
/**
* Method to register a user-defined header with jg-magic-map at runtime
* @param magic The magic number. Needs to be > 1024
* @param clazz The class. Usually a subclass of Header
* @throws IllegalArgumentException If the magic number is already taken, or the magic number is <= 1024
*/
public static void add(short magic, Class clazz) throws IllegalArgumentException {
if(magic < MIN_CUSTOM_MAGIC_NUMBER)
throw new IllegalArgumentException("magic number (" + magic + ") needs to be greater than " +
MIN_CUSTOM_MAGIC_NUMBER);
if(magicMapUser.containsKey(magic))
throw new IllegalArgumentException("magic number " + magic + " for class " + clazz.getName() +
" is already present");
if(classMap.containsKey(clazz))
throw new IllegalArgumentException("class " + clazz.getName() + " is already present");
magicMapUser.put(magic, clazz);
classMap.put(clazz, magic);
}
public static void addProtocol(short id, Class protocol) {
if(id < MIN_CUSTOM_PROTOCOL_ID)
throw new IllegalArgumentException("protocol ID (" + id + ") needs to be greater than or equal to " + MIN_CUSTOM_PROTOCOL_ID);
if(protocol_ids.containsKey(protocol))
throw new IllegalArgumentException("Protocol " + protocol + " is already present");
protocol_ids.put(protocol, id);
}
/**
* Returns a class for a magic number.
* Returns null if no class is found
*
* @param magic the magic number that maps to the class
* @return a Class object that represents a class that implements java.io.Externalizable
*/
public static Class get(short magic) {
return magic < MIN_CUSTOM_MAGIC_NUMBER? magicMap[magic] : magicMapUser.get(magic);
}
/**
* Loads and returns the class from the class name
*
* @param clazzname a fully classified class name to be loaded
* @return a Class object that represents a class that implements java.io.Externalizable
*/
public static Class get(String clazzname, ClassLoader loader) throws ClassNotFoundException {
return Util.loadClass(clazzname, loader != null? loader : ClassConfigurator.class.getClassLoader());
}
public static Class get(String clazzname) throws ClassNotFoundException {
return Util.loadClass(clazzname, ClassConfigurator.class);
}
/**
* Returns the magic number for the class.
*
* @param clazz a class object that we want the magic number for
* @return the magic number for a class, -1 if no mapping is available
*/
public static short getMagicNumber(Class clazz) {
Short i=classMap.get(clazz);
if(i == null)
return -1;
else
return i;
}
public static short getProtocolId(Class protocol) {
Short retval=protocol_ids.get(protocol);
return retval != null? retval : 0;
}
public static Class getProtocol(short id) {
return protocol_names.get(id);
}
public String toString() {
return printMagicMap();
}
public static String printMagicMap() {
StringBuilder sb=new StringBuilder();
SortedSet keys=new TreeSet<>(magicMapUser.keySet());
for(short i=0; i < magicMap.length; i++) {
if(magicMap[i] != null)
keys.add(i);
}
for(Short key: keys) {
sb.append(key).append(":\t").append(key < MIN_CUSTOM_MAGIC_NUMBER? magicMap[key] : magicMapUser.get(key)).append('\n');
}
return sb.toString();
}
public static String printClassMap() {
StringBuilder sb=new StringBuilder();
Map.Entry entry;
for(Iterator it=classMap.entrySet().iterator(); it.hasNext();) {
entry=(Map.Entry)it.next();
sb.append(entry.getKey()).append(": ").append(entry.getValue()).append('\n');
}
return sb.toString();
}
/**
* try to read the magic number configuration file as a Resource form the classpath using getResourceAsStream
* if this fails this method tries to read the configuration file from mMagicNumberFile using a FileInputStream (not in classpath but somewhere else in the disk)
*
* @return an array of ClassMap objects that where parsed from the file (if found) or an empty array if file not found or had en exception
*/
protected static List> readMappings(String name) throws Exception {
InputStream stream;
stream=Util.getResourceAsStream(name, ClassConfigurator.class);
// try to load the map from file even if it is not a Resource in the class path
if(stream == null)
stream=new FileInputStream(name);
return parse(stream);
}
protected static List> parse(InputStream stream) throws Exception {
DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
factory.setValidating(false); // for now
DocumentBuilder builder=factory.newDocumentBuilder();
Document document=builder.parse(stream);
NodeList class_list=document.getElementsByTagName("class");
List> list=new LinkedList<>();
for(int i=0; i < class_list.getLength(); i++) {
if(class_list.item(i).getNodeType() == Node.ELEMENT_NODE) {
list.add(parseClassData(class_list.item(i)));
}
}
return list;
}
protected static Triple parseClassData(Node protocol) {
protocol.normalize();
NamedNodeMap attrs=protocol.getAttributes();
String clazzname;
String magicnumber;
boolean external=false;
magicnumber=attrs.getNamedItem("id").getNodeValue();
clazzname=attrs.getNamedItem("name").getNodeValue();
Node tmp=attrs.getNamedItem("external");
if(tmp != null)
external=Boolean.parseBoolean(tmp.getNodeValue());
return new Triple<>(Short.valueOf(magicnumber), clazzname,external);
}
}
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