/*
* @(#)$Id$
*
* Copyright 2006-2008 Makoto YUI
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.engine.backend;
import java.io.Serializable;
import java.rmi.RemoteException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import xbird.engine.*;
import xbird.engine.Request.Signature;
import xbird.engine.request.PreparedQueryRequest;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.expr.opt.ThreadedVariable;
import xbird.xquery.expr.var.Variable;
import xbird.xquery.meta.*;
import xbird.xquery.parser.visitor.AbstractXQueryParserVisitor;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class PreparedQueryProcessor extends QueryProcessor {
private static final Log LOG = LogFactory.getLog(PreparedQueryProcessor.class);
public PreparedQueryProcessor(ResponseListener handler) {
super(handler);
}
@Override
public Signature associatedWith() {
return Signature.PREPARED_QUERY;
}
@Override
public void fire(RequestContext rc) throws RemoteException {
rc.setFired(System.currentTimeMillis());
final Request request = rc.getRequest();
final Signature rsig = request.getSignature();
if(rsig != Signature.PREPARED_QUERY) {
throw new IllegalStateException("Illegal command is passed to PreparedQueryProcessor: "
+ rsig);
}
final PreparedQueryRequest queryRequest = (PreparedQueryRequest) request;
final XQExpression queryExpr = queryRequest.getCompiledExpression();
if(queryExpr == null) {
throw new IllegalStateException("query was null for: " + queryRequest);
}
final ThreadedVariableCollector collector = new ThreadedVariableCollector();
try {
collector.visit(queryExpr, null);
} catch (XQueryException e) {
throw new RemoteException("failed runnning ThreadVariables", e);
}
final DynamicContext dynEnv = new DynamicContext(new StaticContext());
dynEnv.setQueryExpression(queryExpr);
collector.invokeThreadedVariables(dynEnv); // TODO REVIEWME cancelling
final Sequence<? extends Item> resultSeq;
_runningThreads.put(rc, Thread.currentThread());
try {
resultSeq = queryExpr.eval(null, dynEnv);
} catch (XQueryException e) {
LOG.error("execute failed: \n" + queryExpr, e);
rc.setFault(e);
_resHandler.onResponse(rc);
return;
} finally {
_runningThreads.remove(rc);
}
final Serializable result = wrapResult(resultSeq, queryExpr, queryRequest, dynEnv);
rc.setResult(result);
try {
_resHandler.onResponse(rc);
} catch (RemoteException re) {
LOG.error("The respond for the request '" + rc.getRequest().getIdentifier()
+ "' is failed", re);
}
}
private static final class ThreadedVariableCollector extends AbstractXQueryParserVisitor {
private final List<ThreadedVariable> _threadedVars = new ArrayList<ThreadedVariable>(4);
public ThreadedVariableCollector() {
super();
}
public void invokeThreadedVariables(final DynamicContext dynEnv) {
for(ThreadedVariable v : _threadedVars) {
v.setDynamicContext(dynEnv);
final String threadName = "ThreadedVariable#" + v.getName();
final Thread task = new Thread(v, threadName);
task.setDaemon(true);
task.start();
}
}
@Override
public XQExpression visit(Variable variable, XQueryContext ctxt) throws XQueryException {
if(variable instanceof ThreadedVariable) {
assert (!_threadedVars.contains(variable));
ThreadedVariable thVar = (ThreadedVariable) variable;
_threadedVars.add(thVar);
return variable;
}
return super.visit(variable, ctxt);
}
}
}