// $Id: ClassConfigurator.java,v 1.21.4.2 2008/05/22 13:23:05 belaban Exp $
package org.jgroups.conf;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jgroups.ChannelException;
import org.jgroups.Global;
import org.jgroups.util.Util;
import java.io.ObjectStreamClass;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
/**
* 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 <code>org.jgroups.conf.magicNumberFile</code>.
* It must be relative to one of the classpath elements, to allow the
* classloader to locate the file. If a value is not specified,
* <code>MagicNumberReader.MAGIC_NUMBER_FILE</code> is used, which defaults
* to "jg-magic-map.xml".
*
* @author Filip Hanik
* @author Bela Ban
* @see MagicNumberReader
*/
public class ClassConfigurator {
static volatile ClassConfigurator instance=null; // works under the new JSR 133 memory model in JDK 5
private static final short MIN_CUSTOM_MAGIC_NUMBER=1024;
//this is where we store magic numbers
private final Map<Class,Short> classMap=new ConcurrentHashMap<Class,Short>(); // key=Class, value=magic number
private final Map<Short,Class> magicMap=new ConcurrentHashMap<Short,Class>(); // key=magic number, value=Class
/** Map<Short,ObjectStreamClass> */
private final Map<Short,ObjectStreamClass> streamMapId=new HashMap<Short,ObjectStreamClass>();
/** Map<ObjectStreamClass, Short> */
private final Map<ObjectStreamClass, Short> streamMapClass=new HashMap<ObjectStreamClass, Short>();
protected final Log log=LogFactory.getLog(getClass());
public ClassConfigurator() {
}
public void init() throws ChannelException {
//populate the map
try {
// make sure we have a class for DocumentBuilderFactory
// getClass().getClassLoader().loadClass("javax.xml.parsers.DocumentBuilderFactory");
Util.loadClass("javax.xml.parsers.DocumentBuilderFactory", this.getClass());
MagicNumberReader reader=new MagicNumberReader();
// PropertyPermission not granted if running in an untrusted environment with JNLP.
try {
String mnfile=Util.getProperty(new String[]{Global.MAGIC_NUMBER_FILE, "org.jgroups.conf.magicNumberFile"},
null, null, false, null);
if(mnfile != null) {
if(log.isDebugEnabled()) log.debug("Using " + mnfile + " as magic number file");
reader.setFilename(mnfile);
}
}
catch (SecurityException ex){
}
ObjectStreamClass objStreamClass;
ClassMap[] mapping=reader.readMagicNumberMapping();
if(mapping != null) {
Short m;
for(int i=0; i < mapping.length; i++) {
m=new Short(mapping[i].getMagicNumber());
try {
Class clazz=mapping[i].getClassForMap();
objStreamClass=ObjectStreamClass.lookup(clazz);
if(objStreamClass == null)
throw new ChannelException("ObjectStreamClass for " + clazz + " not found");
if(magicMap.containsKey(m)) {
throw new ChannelException("magic key " + m + " (" + clazz.getName() + ')' +
" is already in map; please make sure that " +
"all magic keys are unique");
}
else {
magicMap.put(m, clazz);
classMap.put(clazz, m);
streamMapId.put(m, objStreamClass);
streamMapClass.put(objStreamClass, m);
}
}
catch(ClassNotFoundException cnf) {
throw new ChannelException("failed loading class", cnf);
}
}
if(log.isDebugEnabled()) log.debug("mapping is:\n" + printMagicMap());
}
}
catch(ChannelException ex) {
throw ex;
}
catch(Throwable x) {
// if(log.isErrorEnabled()) log.error("failed reading the magic number mapping file, reason: " + Util.print(x));
throw new ChannelException("failed reading the magic number mapping file", x);
}
}
public static ClassConfigurator getInstance(boolean init) throws ChannelException {
if(instance == null) {
instance=new ClassConfigurator();
if(init)
instance.init();
}
return instance;
}
public static ClassConfigurator getInstance() throws ChannelException {
return getInstance(false);
}
/**
* 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 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(magicMap.containsKey(magic) || classMap.containsKey(clazz))
throw new IllegalArgumentException("magic number " + magic + " for class " + clazz.getName() +
" is already present");
magicMap.put(magic, clazz);
classMap.put(clazz, magic);
}
/**
* 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 Class get(short magic) {
return magicMap.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 Class get(String clazzname) {
try {
// return ClassConfigurator.class.getClassLoader().loadClass(clazzname);
return Util.loadClass(clazzname, this.getClass());
}
catch(Exception x) {
if(log.isErrorEnabled()) log.error("failed loading class " + clazzname, x);
}
return null;
}
/**
* 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 short getMagicNumber(Class clazz) {
Short i=classMap.get(clazz);
if(i == null)
return -1;
else
return i;
}
public short getMagicNumberFromObjectStreamClass(ObjectStreamClass objStream) {
Short i=streamMapClass.get(objStream);
if(i == null)
return -1;
else
return i.shortValue();
}
public ObjectStreamClass getObjectStreamClassFromMagicNumber(short magic_number) {
ObjectStreamClass retval=null;
retval=streamMapId.get(magic_number);
return retval;
}
public String toString() {
return printMagicMap();
}
public String printMagicMap() {
StringBuilder sb=new StringBuilder();
SortedSet<Short> keys=new TreeSet<Short>(magicMap.keySet());
for(Short key: keys) {
sb.append(key).append(":\t").append(magicMap.get(key)).append('\n');
}
return sb.toString();
}
public 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();
}
/* --------------------------------- Private methods ------------------------------------ */
/* ------------------------------ End of Pivate methods --------------------------------- */
public static void main(String[] args)
throws Exception {
ClassConfigurator test=getInstance(true);
System.out.println('\n' + test.printMagicMap());
}
}