com.mastfrog.giulius.mongodb.async.KnownCollections Maven / Gradle / Ivy
/*
* The MIT License
*
* Copyright 2015 Tim Boudreau.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.mastfrog.giulius.mongodb.async;
import com.mastfrog.settings.Settings;
import com.mastfrog.util.preconditions.Exceptions;
import com.mongodb.async.AsyncBatchCursor;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.async.client.MongoDatabase;
import com.mongodb.async.client.MongoIterable;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import javax.inject.Inject;
import javax.inject.Provider;
import javax.inject.Singleton;
/**
*
* @author Tim Boudreau
*/
@Singleton
class KnownCollections implements Iterable {
private Set knownCollections;
private final Provider dbProvider;
public static final String SETTINGS_KEY_MAX_WAIT_SECONDS = "mongo.list.collections.max.wait.seconds";
private final long maxWaitSeconds;
// PENDING: AsyncMongoClientProvider should create the set maintained
// here, and let initializers augment it, so there is no need for the
// blocking / locking done here
@Inject
KnownCollections(Provider dbProvider, Settings settings) {
this.dbProvider = dbProvider;
maxWaitSeconds = settings.getInt(SETTINGS_KEY_MAX_WAIT_SECONDS, 30);
}
synchronized void add(String created) {
knownCollections().add(created);
}
public boolean exists(String collection) {
return knownCollections().contains(collection);
}
private synchronized Set knownCollections() {
if (knownCollections == null) {
MongoDatabase db = dbProvider.get();
MongoIterable iter = db.listCollectionNames();
CollectionListReceiver recv = new CollectionListReceiver(maxWaitSeconds);
iter.batchCursor(recv);
knownCollections = recv.await();
}
return knownCollections;
}
@Override
public Iterator iterator() {
return knownCollections().iterator();
}
static class CollectionListReceiver implements SingleResultCallback> {
private final SRC src = new SRC();
private final Set allCollections = Collections.synchronizedSet(new HashSet());
private volatile Throwable toThrow;
private volatile AsyncBatchCursor cursor;
private final CountDownLatch latch = new CountDownLatch(1);
private final long maxWaitSeconds;
private CollectionListReceiver(long maxWaitSeconds) {
this.maxWaitSeconds = maxWaitSeconds;
}
@Override
public void onResult(AsyncBatchCursor t, Throwable thrwbl) {
cursor = t;
if (cursor != null) {
cursor.setBatchSize(200);
t.next(src);
}
}
Set await() {
try {
latch.await(maxWaitSeconds, TimeUnit.SECONDS);
if (toThrow != null) {
return Exceptions.chuck(toThrow);
}
return allCollections;
} catch (InterruptedException ex) {
return Exceptions.chuck(ex);
}
}
class SRC implements SingleResultCallback> {
@Override
public void onResult(List t, Throwable thrwbl) {
if (thrwbl != null && toThrow == null) {
toThrow = thrwbl;
}
if (t != null) {
allCollections.addAll(t);
cursor.next(this);
} else {
cursor.close();
latch.countDown();
}
}
}
}
}