/**
* These are the expensive operations (initStandardObjects and compileReader/exec). We do them
* once here, and define this provider as a singleton, so it's only done at provider creation or
* whenever rules are refreshed.
*
* @param rulesCurator
*/
private void compileRules(RulesCurator rulesCurator) {
scriptLock.writeLock().lock();
try {
// XXX: we need a principal to access the rules,
// but pushing and popping system principal could be a bad idea
Principal systemPrincipal = new SystemPrincipal();
ResteasyProviderFactory.pushContext(Principal.class, systemPrincipal);
// Check to see if we need to recompile. we do this inside the write lock
// just to avoid race conditions where we might double compile
Date newUpdated = rulesCurator.getUpdated();
if (newUpdated.equals(this.updated)) {
return;
}
log.debug("Recompiling rules with timestamp: " + newUpdated);
Context context = Context.enter();
context.setOptimizationLevel(9);
scope = context.initStandardObjects(null, true);
try {
script = context.compileString(rulesCurator.getRules().getRules(), "rules", 1, null);
script.exec(context, scope);
((ScriptableObject) scope).sealObject();
this.updated = newUpdated;
} finally {
Context.exit();
}
} finally {
ResteasyProviderFactory.popContextData(Principal.class);
scriptLock.writeLock().unlock();
}
}
public JsRunner get() {
/*
* Create a new thread/request local javascript scope for the JsRules,
* based on the preinitialized global one (which contains our js rules).
*/
// Avoid a write lock if we can
if (!rulesCurator.getUpdated().equals(this.updated)) {
compileRules(this.rulesCurator);
}
Scriptable rulesScope;
scriptLock.readLock().lock();
try {
Context context = Context.enter();
rulesScope = context.newObject(scope);
rulesScope.setPrototype(scope);
rulesScope.setParentScope(null);
Context.exit();
} finally {
scriptLock.readLock().unlock();
}
return new JsRunner(rulesScope);
}