private static Interpreter getInterpreter(String contextId) throws EvalError {
// Get the appropriate interpreter
Interpreter i = null;
boolean createdInterp = false;
synchronized (interpreters) { // serialize two gets of the same name
i = interpreters.get(contextId);
if (i == null) {
i = new Interpreter();
interpreters.put(contextId, i);
createdInterp = true;
}
}
if (createdInterp) {
Log.log("Created context: " + contextId + " (" + i + ")");
// Now configure stdin and stdout to capture 10k of content
// Store references to the circular buffers within the interpreter itself.
// This provides a nice place to store them plus theoretically allows
// advanced use from within the bsh environment.
// On Windows print() outputs \r\n but in XQuery that's normalized to \n
// so the 10k of Java buffer may produce less than 10k of content in XQuery!
OutputStream circularOutput = new CircularByteArrayOutputStream(10240);
PrintStream printOutput = new PrintStream(circularOutput);
i.setOut(printOutput);
i.set("mljamout", circularOutput);
OutputStream circularError = new CircularByteArrayOutputStream(10240);
PrintStream printError = new PrintStream(circularError);
i.setErr(printError);
i.set("mljamerr", circularError);
// Capture the built-in System.out and System.err also.
// (Commented out since System appears global, can't do per interpreter.)
// i.set("mljamprintout", printOutput);
// i.set("mljamprinterr", printError);
// i.eval("System.setOut(mljamprintout);");
// i.eval("System.setErr(mljamprinterr);");
// Need to expose hexdecode() and base64decode() built-in functions
i.eval("hexdecode(String s) { return com.xqdev.jam.MLJAM.hexDecode(s); }");
i.eval("base64decode(String s) { return com.xqdev.jam.MLJAM.base64Decode(s); }");
// Let's tell the context what its id is
i.set("mljamid", contextId);
}
// Update the last accessed time, used for cleaning
i.set("mljamlast", System.currentTimeMillis());
// If it's been long enough, go snooping for stale contexts
if (System.currentTimeMillis() > lastClean + CLEAN_INTERVAL) {
Log.log("Initiated periodic scan for stale context objects");
lastClean = System.currentTimeMillis();
Iterator<Interpreter> itr = interpreters.values().iterator();
while (itr.hasNext()) {
Interpreter interp = itr.next();
Long last = (Long) interp.get("mljamlast");
if (System.currentTimeMillis() > last + STALE_TIMEOUT) {
itr.remove();
Log.log("Staled context: " + interp.get("mljamid") + " (" + interp + ")");
} else if ((System.currentTimeMillis() > last + TEMP_STALE_TIMEOUT)
&& ("" + interp.get("mljamid")).startsWith("temp:")) {
itr.remove();
Log.log("Staled temp context: " + interp.get("mljamid") + " (" + interp + ")");
}
}
}
return i;
}
