io.datakernel.worker.WorkerPoolScope Maven / Gradle / Ivy

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/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * 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 io.datakernel.worker;

import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.Scope;
import io.datakernel.annotation.Nullable;

import java.util.HashMap;
import java.util.Map;

import static io.datakernel.util.Preconditions.checkArgument;
import static io.datakernel.util.Preconditions.checkState;

public final class WorkerPoolScope implements WorkerPools, Scope {
	final Map, WorkerPoolObjects> pool = new HashMap<>();

	@Nullable
	WorkerPool currentWorkerPool;

	@Nullable
	Integer currentWorkerId;

	@SuppressWarnings("unchecked")
	@Override
	public  Provider scope(Key key, Provider unscoped) {
		return () -> {
			checkState(currentWorkerPool != null && currentWorkerId != null,
					"Use WorkerPool to get instances of %s", key);

			WorkerPoolObjects workerPoolObjects = pool.get(key);
			if (workerPoolObjects == null) {
				workerPoolObjects = new WorkerPoolObjects(currentWorkerPool, new Object[currentWorkerPool.workers]);
				pool.put(key, workerPoolObjects);
			}
			checkArgument(workerPoolObjects.workerPool == currentWorkerPool,
					"%s has been created with different WorkerPool", key);
			T[] instances = (T[]) workerPoolObjects.objects;
			T instance = instances[currentWorkerId];
			if (instance == null) {
				instance = unscoped.get();
				instances[currentWorkerId] = instance;
			}
			return instance;
		};
	}

	public Integer getCurrentWorkerId() {
		return currentWorkerId;
	}

	public WorkerPoolObjects getWorkerPoolObjects(Key key) {
		return pool.get(key);
	}
}