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/*
* Copyright (C) 2006 The Android Open Source Project
*
* 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.
*/
package com.android.discovery.recommendation;
import android.net.nsd.NsdManager;
import android.net.nsd.NsdServiceInfo;
import android.util.Pair;
import java.util.LinkedList;
public final class ServiceResolveQueue {
private final NsdManager mNsdManager;
private final LinkedList<Pair<NsdServiceInfo, ResolveCallback>> mQueue = new LinkedList<>();
private final Object mLock = new Object();
private static ServiceResolveQueue sInstance = null;
private Pair<NsdServiceInfo, ResolveCallback> mCurrentRequest = null;
public static void createInstance(NsdManager nsdManager) {
if (sInstance == null) sInstance = new ServiceResolveQueue(nsdManager);
}
public static ServiceResolveQueue getInstance() {
return sInstance;
}
public static void destroyInstance() {
sInstance = null;
}
public interface ResolveCallback {
void serviceResolved(NsdServiceInfo nsdServiceInfo);
}
public ServiceResolveQueue(NsdManager nsdManager) {
mNsdManager = nsdManager;
}
public void queueRequest(NsdServiceInfo serviceInfo, ResolveCallback callback) {
synchronized (mLock) {
Pair<NsdServiceInfo, ResolveCallback> newRequest = Pair.create(serviceInfo, callback);
if (mQueue.contains(newRequest)) return;
mQueue.add(newRequest);
makeNextRequest();
}
}
public void removeRequest(NsdServiceInfo serviceInfo, ResolveCallback callback) {
synchronized (mLock) {
Pair<NsdServiceInfo, ResolveCallback> newRequest = Pair.create(serviceInfo, callback);
mQueue.remove(newRequest);
if ((mCurrentRequest != null) && newRequest.equals(mCurrentRequest)) mCurrentRequest = null;
}
}
private void makeNextRequest() {
synchronized (mLock) {
if (mCurrentRequest != null) return;
if (mQueue.isEmpty()) return;
mCurrentRequest = mQueue.removeFirst();
mNsdManager.resolveService(mCurrentRequest.first, new NsdManager.ResolveListener() {
@Override
public void onResolveFailed(NsdServiceInfo nsdServiceInfo, int i) {
synchronized (mLock) {
if (mCurrentRequest != null) mQueue.add(mCurrentRequest);
makeNextRequest();
}
}
@Override
public void onServiceResolved(NsdServiceInfo nsdServiceInfo) {
synchronized (mLock) {
if (mCurrentRequest != null) {
mCurrentRequest.second.serviceResolved(nsdServiceInfo);
mCurrentRequest = null;
}
makeNextRequest();
}
}
});
}
}
}
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