| /* |
| * Copyright 2016 The gRPC Authors |
| * |
| * 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.grpc.internal; |
| |
| import java.util.Collections; |
| import java.util.IdentityHashMap; |
| import java.util.Set; |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Aggregates the in-use state of a set of objects. |
| */ |
| @NotThreadSafe |
| public abstract class InUseStateAggregator<T> { |
| |
| private final Set<T> inUseObjects = Collections.newSetFromMap(new IdentityHashMap<T,Boolean>()); |
| |
| /** |
| * Update the in-use state of an object. Initially no object is in use. |
| * |
| * <p>This may call into {@link #handleInUse} or {@link #handleNotInUse} when appropriate. |
| */ |
| public final void updateObjectInUse(T object, boolean inUse) { |
| int origSize = inUseObjects.size(); |
| if (inUse) { |
| inUseObjects.add(object); |
| if (origSize == 0) { |
| handleInUse(); |
| } |
| } else { |
| boolean removed = inUseObjects.remove(object); |
| if (removed && origSize == 1) { |
| handleNotInUse(); |
| } |
| } |
| } |
| |
| public final boolean isInUse() { |
| return !inUseObjects.isEmpty(); |
| } |
| |
| /** |
| * Returns {@code true} if any of the given objects are in use. |
| * |
| * @param objects The objects to consider. |
| * @return {@code true} if any of the given objects are in use. |
| */ |
| public final boolean anyObjectInUse(Object... objects) { |
| for (Object object : objects) { |
| if (inUseObjects.contains(object)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Called when the aggregated in-use state has changed to true, which means at least one object is |
| * in use. |
| */ |
| protected abstract void handleInUse(); |
| |
| /** |
| * Called when the aggregated in-use state has changed to false, which means no object is in use. |
| */ |
| protected abstract void handleNotInUse(); |
| } |