public static PiHelper load_pi_helper(
PiHelper pi_helper_cache, ConditionalDistribution pxu, Distribution[] pi_messages)
throws Exception {
if (pi_messages.length == 0) return new TrivialPiHelper();
Vector seq = new Vector();
seq.addElement(pxu.getClass());
for (int i = 0; i < pi_messages.length; i++) seq.addElement(pi_messages[i].getClass());
if (pi_helper_cache != null
&& MatchClassPattern.matches(pi_helper_cache.description(), seq, new int[1], new int[1]))
return pi_helper_cache;
Class c = find_helper_class(seq, "pi");
return (PiHelper) c.newInstance();
}
/**
* Check the helpers currently stored in the helper cache to see if any of them can handle the
* sequence we've just been given. This avoids pinging the belief network context to get a helper
* list.
*/
public static Class find_helper_class1(
Vector seq, String helper_type, int[] max_class_score, int[] max_count_score)
throws ClassNotFoundException {
int[] class_score1 = new int[1], count_score1 = new int[1];
max_class_score[0] = -1;
max_count_score[0] = -1;
Class cmax_score = null;
for (Enumeration e = helper_cache.keys(); e.hasMoreElements(); ) {
try {
HelperCacheKey key = (HelperCacheKey) e.nextElement();
if (!key.helper_type.equals(helper_type)) continue;
Class c = (Class) helper_cache.get(key);
SeqTriple[] sm = (SeqTriple[]) invoke_description(c);
if (sm == null) continue; // apparently not a helper class
if (MatchClassPattern.matches(sm, seq, class_score1, count_score1)) {
if (class_score1[0] > max_class_score[0]
|| (class_score1[0] == max_class_score[0] && count_score1[0] > max_count_score[0])) {
cmax_score = c;
max_class_score[0] = class_score1[0];
max_count_score[0] = count_score1[0];
}
}
} catch (Exception e2) {
} // eat it; stagger forward
}
if (Global.debug > 1)
System.err.println(
"PiHelperLoader.find_helper_class1: helper "
+ (cmax_score == null ? "is NOT" : "is")
+ " in cache.");
if (cmax_score == null) // no luck; try to get a helper list from the bnc & plunge ahead
return find_helper_class0(seq, helper_type, max_class_score, max_count_score);
else // success!
return cmax_score;
}
/**
* Contact a belief network context, get the helper list, and search the list to see if there's a
* helper which matches the type sequence specified. If there's more than one helper which
* matches, find the ``best fit.''
*
* <p>The class and count scores of the best-fitting helper class are written into
* <tt>max_class_score[0]</tt> and <tt>max_count_score[0]</tt>, respectively.
*/
public static Class find_helper_class0(
Vector seq, String helper_type, int[] max_class_score, int[] max_count_score)
throws ClassNotFoundException {
long t0 = System.currentTimeMillis();
if (bnc != null) // make sure the reference is still alive
try {
bnc.get_name();
} catch (RemoteException e) {
bnc = null;
}
if (bnc == null) // need to locate a context
{
String cb = System.getProperty("java.rmi.server.codebase", "http://localhost");
long tt0 = System.currentTimeMillis();
try {
bnc = BeliefNetworkContext.locate_context(new URL(cb).getHost());
} catch (Exception e) {
throw new ClassNotFoundException("nested: " + e);
}
}
String[] helperlist;
try {
helperlist = bnc.get_helper_names(helper_type);
} catch (RemoteException e) {
throw new ClassNotFoundException("bnc.get_helper_names failed");
}
int[] class_score1 = new int[1], count_score1 = new int[1];
max_class_score[0] = -1;
max_count_score[0] = -1;
Class cmax_score = null;
for (int i = 0; i < helperlist.length; i++) {
try {
Class c = RMIClassLoader.loadClass(helperlist[i]);
SeqTriple[] sm = (SeqTriple[]) invoke_description(c);
if (sm == null) continue; // apparently not a helper class
if (MatchClassPattern.matches(sm, seq, class_score1, count_score1)) {
if (class_score1[0] > max_class_score[0]
|| (class_score1[0] == max_class_score[0] && count_score1[0] > max_count_score[0])) {
cmax_score = c;
max_class_score[0] = class_score1[0];
max_count_score[0] = count_score1[0];
}
}
} catch (Exception e2) {
System.err.println("PiHelperLoader: attempt to load " + helperlist[i] + " failed; " + e2);
}
}
if (cmax_score == null) {
System.err.println("find_helper_class0: failed; helper list:");
for (int i = 0; i < helperlist.length; i++) System.err.println("\t" + helperlist[i]);
String s = "";
for (Enumeration e = seq.elements(); e.hasMoreElements(); ) {
try {
Class c = (Class) e.nextElement();
s += c.getName() + ",";
} catch (NoSuchElementException ee) {
s += "???" + ",";
}
}
throw new ClassNotFoundException("no " + helper_type + " helper for sequence [" + s + "]");
}
// FOR NOW IGNORE THE POSSIBILITY OF TWO OR MORE MATCHES !!!
return cmax_score;
}