* It is also responsible for creating cores, and giving logging and universe access to a VM. *
* A loader is not "valid" until both init() and create() are called. *
* @author Erich P. Gatejen
* @version 1.0
* Version History
* EPG - Initial - 12may03
*
*/
public class VMLoader {
// universe
public SystemContext sc;
// logger
public AutohitLogInjectorWrapper log;
// routine cache
static private Hashtable cache;
// core factory cache
private VMCoreFactory corefactory;
/**
* Default Constructor.
*/
public VMLoader() {
if (cache == null)
cache = new Hashtable();
corefactory = new VMCoreFactory();
}
/**
* Initializer.
* @param sctx the system context
*/
public void init(SystemContext sctx) {
sc = sctx;
log = sc.getRootLogger();
}
/**
* Create a core.
*/
public VMCore create() {
// create it
VMCore core = corefactory.allocate();
// mirror all the invoker props
Hashtable iprop = sc.getInvokerProperties();
String ikey;
Object ivalue;
for (Enumeration e = iprop.keys(); e.hasMoreElements();) {
try {
ikey = (String)e.nextElement();
ivalue = iprop.get(ikey);
core.store(ikey, ivalue);
} catch (Exception ecc) {
// ignore and just disqualify that entry
}
}
return core;
}
/**
* Load
* @param name of routine to load
* @return an executable
* @throws VMException unable to load.
*/
public VMExecutable load(String name) throws VMException {
if (cache.containsKey(name)) {
// cache hit
//log.debug("Loader(routine-basic): cache hit [" + name + "].");
return (VMExecutable) cache.get(name);
}
VMExecutableWrapper wrapper = new VMExecutableWrapper();
try {
log.debug(
"Loader(routine-basic): Loading [" + name + "].",
AutohitErrorCodes.CODE_INFORMATIONAL_OK_VERBOSE);
Universe u = sc.getUniverse();
InputStream is =
u.getStream(
AutohitProperties.literal_UNIVERSE_CACHE
+ AutohitProperties.literal_NAME_SEPERATOR
+ name);
wrapper.load(is);
} catch (UniverseException e) {
if (e.numeric == UniverseException.UE_OBJECT_DOESNT_EXIST) {
throw new VMException(
"Loader(routine-basic): Loading program "
+ name
+ " not compiled and available. ",
VMException.CODE_VM_EXEC_DOES_NOT_EXIST_FAULT,
e);
} else {
throw new VMException(
"Loader(routine-basic): Loading program "
+ name
+ " caused a Universe Exception: "
+ e.getMessage(),
VMException.CODE_VM_SUBSYSTEM_FAULT,
e);
}
} catch (Exception e) {
throw new VMException(
"Loader(routine-basic): Loading program "
+ name
+ " caused a fundimental Exception: "
+ e.getMessage(),
VMException.CODE_VM_GENERAL_FAULT,
e);
}
cache.put(name, wrapper.exec);
return wrapper.exec;
}
/**
* Get a call. If it isn't in the cache, load it. There is no thread
* safety here at all! However, it shouldn't matter since there is a
* loader per VM.
* @param name of routine to load
* @param core a VMCore that holds a callcache
* @param li log injector to give to the call
* @return runnable call
* @throws VMException unable to load.
*/
public Call get(String name, VMCore core, AutohitLogInjectorWrapper li) throws VMException {
if (core.callcache.containsKey(name)) {
// cache hit
//log.debug(
// "Loader(call-basic): cache hit [" + name + "].",
// AutohitErrorCodes.LOG_INFORMATIONAL_OK);
return (Call) core.callcache.get(name);
}
Call c = null;
try {
String decoratedName = "autohit.call.Call_" + name.toUpperCase();
Class t = Class.forName(decoratedName);
c = (Call) t.newInstance();
Universe u = sc.getUniverse();
c.load(core, sc, li);
log.debug(
"Loader(call-basic): Instantiated a [" + name + "].",
AutohitErrorCodes.CODE_INFORMATIONAL_OK_VERBOSE);
core.callcache.put(name, c);
} catch (ClassNotFoundException ef) {
throw new VMException(
"Loader(call-basic): CALL does not exist. error="
+ ef.getMessage(),
VMException.CODE_VM_GENERAL_FAULT,
ef);
} catch (CallException ex) {
throw new VMException(
"Loader(call-basic): Instantiation error for ["
+ name
+ "]. Not aborting, but state of CALL undefined. Error="
+ ex.getMessage(),
VMException.CODE_VM_CALL_FAULT,
ex);
} catch (Exception e) {
throw new VMException(
"Loader(call-basic): CALL does not exist. error="
+ e.getMessage(),
VMException.CODE_VM_GENERAL_FAULT,
e);
}
return c;
}
/**
* Flush the entire routine cache
* @throws VMException if it locked by something else.
*/
public void flush() {
Hashtable holding = cache;
synchronized (holding) {
cache = new Hashtable();
}
}
/**
* Flush a specific routine out fo the cache
* @throws VMException if it locked by something else.
*/
public void flush(String name) {
Hashtable holding = cache;
synchronized (holding) {
try {
cache.remove(name);
} catch (Exception e) { // dont care
}
}
}
/**
* Gets a property from the SystemContext. Normally, you should handle
* all system interaction through a Universe. Don't use this unless you
* have no choice.
* Returns the value or null if it does not exist
* @param name of the property
* @return the value as a String or null if it doesn't exist
*/
public String property(String name) {
String thang = null;
try {
ExtendedProperties ep = sc.getPropertiesSet();
thang = (String) ep.getProperty(name);
} catch (Exception e) {
// nothing. null will return
}
return thang;
}
}